Tesis: "Muscle and tendon"

1

O'Brien, Thomas Daniel. "Developmental changes in muscle and tendon structure and function". Thesis, Manchester Metropolitan University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.509363.

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2

Endo, Ken Ph D. Massachusetts Institute of Technology. "A model of muscle-tendon function in human walking". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/75633.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 109-113).
In order to motivate the design of legged machines that walk as humans do, this thesis investigates how leg muscles and tendons work mechanically during level-ground human walking at self-selected speeds. I hypothesize that quasi- passive, series-elastic clutch units spanning the knee joint in a musculoskeletal arrangement can capture the dominant mechanical behaviors of the human knee in level-ground walking. As a preliminary evaluation of this hypothesis, I develop an under-actuated model of the human leg in walking where each muscle-tendon unit spanning the knee joint is represented as a simple linear spring in series with a clutch. I vary model parameters, or spring constants and clutch engagement times, using an optimization scheme that minimizes ankle and hip actuator work while still maintaining human-like knee mechanics. For model evaluation, kinetic and kinematic gait data are employed from nine participants walking across a level-ground surface at self-selected gait speeds. With this under-actuated leg model, I find good agreement between model quasi-passive knee torque and experimental knee values, suggesting that a knee actuator is not necessary for level-ground robotic ambulation at self-selected gait speeds. As a further evaluation of the hypothesis of spring-like muscle-tendon behavior about the knee joint, a forward dynamics control scheme for the under-actuated model is developed. Hill-type muscle models are employed to model the ankle soleus and hip monoarticular muscles. Further, the model's series-elastic clutches are engaged with a simple state machine based on electromyography (EMG) data from the literature. Muscles are controlled with simple feedback controls representing the reflexive architecture of the human neuromuscular system. Following an optimization procedure, the model is shown to predict joint and muscle biomechanics, as well as the metabolism of walking humans, supporting the idea that muscle-tendon units spanning the human knee joint mainly operate as spring elements during neural activation, affording the relatively high metabolic walking economy of humans.
by Ken Endo.
Ph.D.

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3

Cook, Christopher S. "The dynamic properties of a human muscle-tendon complex". Thesis, University of Birmingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313923.

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4

Thongnuek, Peerapat. "The role of tendon matrix proteins in muscle adhesion". Thesis, University of Cambridge, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709043.

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5

Rook, Karen Mary. "The storage of elastic energy by the muscle tendon complex : the effects of tendon compliance and muscle strength and the implications for locomotion". Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321576.

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6

Pontén, Eva. "Tendon transfer mechanics and donor muscle properties : implications in surgical correction of upper limb muscle imbalance /". Umeå : Integrativ medicinsk biologi, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-167.

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7

Létocart, Adrien. "Capacités d’adaptations tendineuses à l’entraînement : effet de l'âge". Thesis, Compiègne, 2018. http://www.theses.fr/2018COMP2465/document.

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Un des problèmes majeurs contribuant à la réduction de la mobilité chez la personne âgée est la hausse de l’occurrence des chutes. La capacité à maintenir l’équilibre ou la stabilité posturale a été précédemment associée à la structure et aux propriétés mécaniques des tendons du membre inférieur. Cette étude fut menée afin d’évaluer les effets de l’intensité d’entrainement et de l’âge sur les changements de l’architecture tendineuse et ses propriétés mécaniques ainsi que sur les adaptations musculaires du membre inférieur. Ce projet avait ainsi pour objectif de comparer les effets de deux conditions d’entrainement pour un volume équivalent (intensité modérée (55% d’une répétition maximale (1RM) vs élevée (80% de 1RM)) sur deux groupes musculaires différents (quadriceps vs triceps sural), sur les adaptations des tendons d’Achille et patellaire associés aux adaptations de ces groupes musculaires respectifs. Enfin, le dernier objectif de cette étude était de montrer si des changements de la balance posturale et de la capacité de mouvement pouvaient s’expliquer par les évolutions de l’architecturale et de propriétés mécaniques des structures musculaires et tendineuses avec l’âge. Dix hommes jeunes (Age : 24.8 ± 3.6) et 27 séniors (Age : 69.9 ± 4.5) sédentaires ont été recrutés et ont participé à un programme d’entrainement en résistance de 12 semaines (3 fois/semaine) sur les muscles du triceps sural et du quadriceps. Le groupe de jeunes (n=10) ainsi qu’un groupe de séniors (n=13) ont participé à un programme d’entrainement modéré correspondant à 55% de 1RM, tandis qu’un deuxième groupe de seniors s’est vu imposer une intensité d’entrainement de 80% de 1RM (n=14). Chaque groupe a reçu exactement le même volume d'entraînement sur les muscles quadriceps et triceps sural en utilisant des machines de musculation guidées : la presse à jambes, l'extension des jambes et la machine à mollets assis. Afin de pouvoir obtenir les paramètres nécessaires à cette étude, l’utilisation d’ergomètres, d’images échographiques et IRM et d’un système de capture de mouvement ont été nécessaires. En comparant deux populations de jeunes et de séniors, cette étude a ainsi permis de quantifier une diminution de la force, couplée ou non suivant le tendon considéré à une diminution des propriétés intrinsèques du matériau tendineux. L’obtention de l’architecture musculaire a permis de construire les courbes d’évolutions de la section de chacun des muscles du quadriceps et du triceps sural pour les populations jeunes et séniors. Les deux conditions d’entrainement nous ont permis de mettre en évidence une amélioration des propriétés mécaniques des tendons d’Achille et patellaire, et plus sensiblement le tendon d’Achille, sur les deux populations jeunes et séniors sans toutefois observer de gain supplémentaire pour une intensité élevée. Des gains similaires suite à la période d’entrainement ont pu être observés chez les séniors sur les volumes des muscles du triceps sural et du quadriceps sans distinction de l’intensité considérée. L’analyse du mouvement nous a permis de mettre en évidence l’amélioration de la stabilité posturale et une évolution de la stratégie de flexion du tronc lors d’un lever de chaise suite à l’entrainement chez les séniors sans bénéfice supplémentaire entre une intensité modérée et élevée. De plus, les effets de l’âge sur les propriétés mécaniques des tendons ont pu être corrélés avec les performances liées aux exercices de stabilité posturale, de saut et de lever de chaise. Ce travail a donc permis de quantifier les effets de l’âge sur les capacités musculaires, tendineuses et de mouvement. Cette étude nous a également permis de mettre en évidence un seuil d’intensité d’entrainement (55% de 1RM) à partir duquel les personnes âgées ne semblent pas montrer de gain additionnel pour les systèmes musculaires et tendineux. Ce travail permet donc de proposer une optimisation de l’activité physique prescrite à la personne âgée ou vieillissante
The ability to maintain balance has previously been associated with the structure and mechanical properties of the tendons of the lower limb. In order to evaluate the effects of training intensity (moderate vs. high intensity) and age on changes in tendon architecture (Achilles and patellar) and its mechanical properties, 10 young men and 27 sedentary seniors participated in a 12-week resistance training program (3 times/week) on the muscles of the triceps surae (TS) an quadriceps (QF). The young group and a senior group participated in a moderate training program corresponding to 55% of IRM (maximum repetition), while a second group of seniors received a training intensity of 80% of IRM. Each group received the same volume of training on the TS and QF muscles using guided weight machines. The use of ergometers, ultrasound and MRI images and a motion capture system were required. A decrease in strength, coupled or not depending on the tendon under consideration, and a decrease in the properties of the tendon material have been quantified with age. Evolution curves of each of the QF and TS muscles for both populations were constructed. The two training conditions showed an improvement in the mechanical properties of the Achilles and patellar tendons, and more significantly the Achilles, on both populations without any additional gain for a high intensity. Similar gains after training between the two intensities could be observed in seniors on muscle volumes. The improvement of postural stability and an evolution of the strategy during a chair lift were observed in seniors without any additional benefit between the two training intensities. This made it possible to quantify the effects of age on muscle, tendon and movement abilities by highlighting a threshold of training intensity (55% of IRM) from which seniors do not seem to show any additional gain. This work therefore makes it possible to propose an optimization of the physical activity prescribed to the elderly person

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8

Pontén, Eva. "Tendon transfer mechanics and donor muscle properties : implications in surgical correction of upper limb muscle imbalance". Doctoral thesis, Umeå universitet, Institutionen för integrativ medicinsk biologi (IMB), 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-167.

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Tendon transfer surgery is used to improve the hand function of patients with nerve injuries, spinal cord lesions, cerebral palsy (CP), stroke, or muscle injuries. The tendon of a muscle, usually with function opposite that of the lost muscle function, is transferred to the tendon of the deficient muscle. The aim is to balance the wrist and fingers to achieve better hand function. The position, function, and length at which the donor muscle is sutured is essential for the outcome for the procedure. In these studies the significance of the transferred muscle’s morphology, length and apillarization was investigated using both animal and human models. Immunohistochemical, biochemical, and laser diffraction techniques were used to examine muscle structure. In animal studies (rabbit), the effects of immobilization and of tendon transfers at different muscle lengths were analyzed. Immobilization of highly stretched muscles resulted in fibrosis and aberrant regeneration. A greater pull on the tendon while suturing a tendon transfer resulted in larger sarcomere lengths as measured in vivo. On examination of the number of sarcomeres per muscle fiber and the sarcomere lengths after 3 weeks of immobilization and healing time, we found a cut-off point up to which the sarcomerogenesis was optimal. Transfer at too long sarcomere lengths inhibited adaptation of the muscle to its new length, probably resulting in diminished function. In human studies we defined the sarcomere lengths of a normal human flexor carpi ulnaris muscle through the range of motion, and then again after a routinely performed tendon transfer to the finger extensor. A calculated model illustrated that after a transfer the largest force was predicted to occur with the wrist in extension. Morphological studies of spastic biceps brachii muscle showed, compared with control muscle, smaller fiber areas and higher variability in fiber size. Similar changes were also found in the more spastic wrist flexors comparing with wrist extensors in children with CP. In flexors, more type 2B fibers were found. These observations could all be due to the decreased use in the spastic limb, but might also represent a specific effect of the spasticity. In children and adults with spasticity very small fibers containing developmental myosin were present in all specimens, while none were found in controls. These fibers probably represent newly formed fibers originating from activated satellite cells. Impaired supraspinal control of active motion as well as of spinal reflexes, both typical of upper motor syndrome, could result in minor eccentric injuries of the muscle, causing activation of satellite cells. Spastic biceps muscles had fewer capillaries per cross-sectional area compared to age-matched controls, and also a smaller number of capillaries around each fiber. Nevertheless, the number of capillaries related to the specific fiber area was normal, and hence the spastic fibers are sufficiently supplied with capillaries. This study shows that the length of the muscle during tendon transfer is crucial for optimization of force output. Laser diffraction can be used for accurate measurement of sarcomere length during tendon transfer surgery. Wrist flexor muscles have more morphological alterations typical of spasticity compared to extensors.

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9

Heikkinen, J. (Juuso). "Recovery of calf muscle isokinetic strength after acute Achilles tendon rupture". Doctoral thesis, Oulun yliopisto, 2017. http://urn.fi/urn:isbn:9789526216195.

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Abstract Achilles tendon rupture (ATR) conservative treatment result usually good clinical outcome, but despite the treatment method calf muscle strength deficit persist. Recent evidence suggests that surgery might surpass conservative treatment in restoring strength after ATR, but structural explanations for surgery-related improved strength remain uncertain. The purposes of this thesis were to compare calf muscle isokinetic strength recovery, calf muscle volume, fatty degeneration and AT elongation after conservative treatment or after open surgical repair of ATR. An additional aim was to assess the role of fascial augmentation in terms of calf muscle isokinetic strength recovery, AT elongation, calf muscle volume atrophy and fatty degeneration, and their relationship with calf muscle isokinetic strength in long-term follow-up after ATR surgery. Surgery resulted in 10% to 18% greater plantar flexion strength (P = 0.037) compared to conservative treatment. The mean differences between affected and healthy soleus muscle volumes were -18% after surgery and -25% after conservative treatment (P = 0.042). At 18 months, AT were, on average 19 mm longer in patients treated conservatively compared to surgery (P < 0.001). At 18 months, patients with greater (2–3) fatty degeneration had lower soleus muscle volumes and plantar flexion strength in the healthy leg. In long term, augmentation did not affect any of the strength variables, but the injured side showed 12% to 18% strength deficit compared with the healthy side (P < 0.001). The AT was, on average, 12 mm longer in the affected leg than in the healthy leg (P < 0.001). The mean soleus muscle volume was 13% lower in the affected leg than in the healthy leg (P < 0.001). The mean volumes of the medial- and lateral gastrocnemius muscles were 12% and 11% lower in the affected leg than in the healthy leg, respectively (P < 0.001). AT elongation correlated substantially with plantar strength deficit (ρ = 0.51, P < 0.001) and with both gastrocnemius (ρ = 0.46, P = 0.001) and soleus muscle atrophy (ρ = 0.42, P = 0.002). Calf muscle fatty degeneration was more common in the affected leg compared healthy leg (P ≤ 0.018). In conclusion, surgery of ATR restored calf muscle isokinetic strength earlier and more completely than conservative treatment. Conservative treatment resulted in greater soleus muscle atrophy and AT elongation compared surgery, which may partly explain the surgery related better strength results. Augmentation provided no long-term benefits compared with simple suturation, and a 12 to 18% plantar flexion strength deficit compared to the healthy side persisted. AT elongation may explain the smaller calf muscle volumes, greater fatty degeneration, and plantar flexion strength deficit observed in long-term follow-up after surgical repair of ATR
Tiivistelmä Akillesjännerepeämän (ATR) konservatiivisella ja leikkaushoidolla hoidolla saavutetaan hyvät kliiniset tulokset. Viimeisimmät tutkimukset kuitenkin viittaavat leikkaushoidolla saavutettavan paremmat voimat kuin konservatiivisella hoidolla, mutta rakenteelliset selitykset leikkaushoidon paremmalle pohjelihaksen voimille ovat epäselviä. Työn tarkoituksena oli verrata pohjelihaksen isokineettisten voimien palautumista, pohjelihastilavuuksia, rasvadegeneraatiota ja akillesjänteen (AT) pidentymistä ATR:n konservatiivisen- ja leikkaushoidon jälkeen. Tarkoituksena oli arvioida lihaskalvovahvikkeen merkitystä pohjelihaksen isokineettisten voimien palautumisessa pitkäaikaisseurannassa. Lisäksi tutkimme AT pidentymisen, pohjelihastilavuuksien ja rasvadegeneraation suhdetta pohjelihaksen isokineettisiin voimiin ATR:n leikkaushoidon jälkeen 14 v seurannassa. Leikkaushoidolla saavutettiin 10–18 % paremmat pohjelihaksen voimat verrattuna konservatiiviseen hoitoon. Leikkaushoidon jälkeen soleuslihasten tilavuuksien puoliero terveen jalan hyväksi oli 18 % ja konservatiivisen hoidon jälkeen 25 %. 18 kk kohdalla konservatiivisesti hoidettujen AT oli 19 mm pidempi verrattuna leikkauksella hoidettuihin. 18 kk kohdalla potilaat, joilla vamma jalan soleuslihaksen rasva-degeneraatio oli korkea (2–3), kärsivät suuremmasta soleuslihaksen atrofiasta ja pohjelihaksen voima puolierosta. Voimat eivät muuttuneet 12 kk ja 14 v kontrollien välillä. Lihaskalvovahvikkeella ei ollut merkitystä voimien palautumisessa pelkkään suoraan ompeluun verrattuna, mutta vammapuoli jäi 10–18 % heikommaksi verrattuna terveeseen jalkaan. Vammajalan akillesjänne oli 12 mm pidempi terveeseen jalkaan verrattuna. Vammajalan kolmipäisen pohjelihaksen tilavuus oli 11–13 % pienempi verrattuna terveeseen jalkaan. Akillesjänteen pituus korreloi pohjelihaksen voimapuolieron sekä pohjelihasatrofian kanssa. Akillesjännerepeämän leikkaushoidolla pohjelihaksen isokineettiset voimat palautuvat nopeammin ja täydellisemmin kuin konservatiivisella hoidolla. Leikkaushoitoon verrattuna konservatiivinen hoito johtaa suurempaan soleuslihaksen atrofiaan ja akillesjänteen pidentymään, mikä selittää osittain leikkaushoidon paremmat voimatulokset. 14 v seurannassa lihaskalvovahvikkeesta ei ole etua akillesjännerepeämän leikkaushoidossa. Akillesjännerepeämän leikkaushoidosta huolimatta potilaalle jää terveeseen jalkaan verrattuna 10–18 % pohjelihasten voimapuoliero. Akillesjänteen pidentyminen mahdollisesti selittää pohjelihasten atrofian, rasvadegeneraation ja pysyvän pohjelihasten voimapuolieron akillesjännerepeämän leikkaushoidon jälkeen 14 v seurannassa

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10

Simpson, Carey Lynn. "Muscle and tendon characteristics after six weeks of overloaded stretch training". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54149.

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Stretching is used to maintain mobility, increase range of motion and rehabilitate muscles after injury. It is rarely suggested as a modality for increasing muscle size in humans, although animal studies have reported stretch induced muscle hypertrophy. The purpose of this study was to examine whether six weeks of passive stretching of the plantar flexors would stimulate muscle hypertrophy. The first hypothesis was that stretch training would induce muscle hypertrophy, increase fascicle lengths and decrease pennation angles of the medial and lateral gastrocnemius without altering the Achilles tendon, but changes in muscle architecture would be non-uniform between the gastrocnemii. The second hypothesis was stretch training would decrease maximal force and electromyography (EMG) activity of the plantar flexors through shifting the length tension relationship without changing voluntary activation or reflex activity. Eleven males stretched the non-dominant plantar flexors for six consecutive weeks by using a leg press to passively load the ball of the foot. The load was 20% of the baseline maximal voluntary contraction. EMG was monitored on-line for each session to ensure the subject was stretching and not contracting, which would be indicated by muscle activity. At week zero, three, six and one week after the completion of stretching ultrasound was used to measure muscle architectural and tendon changes. Force, EMG, twitch interpolation, reflex activity, contractile properties and body anthropometry were also measured. Both hypotheses were supported. Muscle depth increased 10.3% (p=0.04) by week three in the stretched leg with a 25% (p<0.001) increase in the length of the muscle fascicles in the muscle tendon junction, and 5.1% (p=0.01) increase in the fascicles of the muscle belly (n=3600). The pennation angle (n=3600) decreased (p=0.02) with no change in the tendon (p=0.95). Muscle force decreased 10.5% (p=0.008) at week six, with a reduction in EMG amplitude (p<0.001) and no change in voluntary activation (95.48% ± 0.92, p>0.05) or reflex activity (p>0.05). These data indicated six weeks of overloaded stretch training of the plantar flexors stimulated muscle hypertrophy but also caused significant reductions in force through an alteration in the length tension relationship.
Graduate Studies, College of (Okanagan)
Graduate

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11

Lichtwark, Glen Anthony. "The role of muscle tendon unit elasticity in real life activities". Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444942/.

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The interaction of a muscle and associated tendon during dynamic activities such as locomotion is critical for both force production and economical movement. It is generally assumed that, under sub-maximal conditions, muscle activation patterns are optimised to achieve maximum efficiency of work. Here, I explore the interaction between the contractile component (CC) and the elastic tendinous tissue to understand the relationship between a muscle's power output and efficiency. In this thesis, I examine the interaction of the CE and the elastic tendinous tissue and its effect on power output and efficiency of muscle using both experimental and modelling techniques. In the first chapter, a model of muscle energetics is developed and validated against dynamic muscle contractions of different muscle types. I then used this model to explore how optimal muscle power and efficiency varies with different activation conditions, clastic properties and length change trajectories. The third and forth chapter presents experiments which explore ultrasound measurement techniques for determining the length changes and mechanical properties of the human gastrocnemius medial is (GM) muscle fibres and Achilles tendon (AT) respectively. I then used similar techniques to explore musclc-tcndon unit (MTU) interaction during gait under different gait conditions. Specifically, I explore how GM power output and efficiency vary with different speeds and inclination and explore how variation in tendinous compliance might influence muscle efficiency. The results suggest that muscles remain highly efficient due to compliant tendons allowing muscle fibres to act at highly powerful and efficient velocities. However variation in power output and particularly muscle function affects the efficiency of muscle. Finally, I determined that the optimal value of tendon stiffness for maximum GM efficiency during walking and running is close to that determined experimentally.

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12

Potts, Geoffrey. "Biomechanic analysis of 'heavy-load eccentric calf muscle' exercise used in the rehabilitation of achilles tendinosis a dissertation submitted in partial fulfilment for the degree of Master of Health Science, Auckland University of Technology, January 2005". Full thesis. Abstract, 2005. http://puka2.aut.ac.nz/ait/theses/PottsG.pdf.

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13

Farris, Dominic James. "In vivo assessment of the elastic behaviour of the triceps surae muscle-tendon-complex : implications for achilles tendon injury". Thesis, University of Bath, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520825.

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14

Alahmari, Sami Khaloufah M. "Muscle force production and neuromuscular fatigue responses to neuromuscular electrical stimulation and tendon vibration". Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/236174/1/Sami_Alahmari_Thesis.pdf.

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Neuromuscular electrical stimulation is an intervention that produces artificial muscle contractions and is used to rehabilitate people with motor impairments. However, a typical problem is the occurrence of rapid fatigue, which limits the training stimulus. This thesis investigated whether the addition of tendon vibration and concurrent activation of upper limb muscles could minimise fatigue and maximise torque produced by the calf muscles during neuromuscular electrical stimulation. The experiments in this thesis showed that superimposition of tendon vibration can increase the amount of torque produced by calf muscles, and that the addition of sustained handgrip contraction could further increase this torque.

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15

Ingrado, Philippe d'. "Le complexe musculo-tendineux du genou (Biométrie et structure morpho-fonctionnelle)". Montpellier 1, 1997. http://www.theses.fr/1997MON11147.

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16

Galantis, Apostolos. "Contractile and elastic behaviour of human muscle-tendon complexes with inertial loading". Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269846.

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17

Lebellé, Jean-Luc. "Contribution a la connaissance de la constitution et du fonctionnement des plis vocaux (cordes vocales)". Rennes 1, 1994. http://www.theses.fr/1994REN1M098.

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18

Joseph, Corey William Julian. "Musculoskeletal stiffness and Achilles tendon mechanical property changes following exercise-induced muscle damage". Thesis, Australian Catholic University, 2012. https://acuresearchbank.acu.edu.au/download/01e5d23cde80fdaaff7c18a3e861191f10912e63b462b4462ca719c6bf5d7fff/29244544/64937_downloaded_stream_162.pdf.

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This thesis investigated the affect of exercise induced muscle damage (EIMD) on musculoskeletal stiffness (MSS), Achilles tendon (AT) stiffness and AT strain. Furthermore, this thesis determined the reliability of a protocol used to measure MSS with the aim to apply this protocol in the investigation of the EIMD associated changes in MSS, AT stiffness and AT strain. Three studies were conducted as part of this thesis.

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19

Rice, Paige Elizabeth. "Determining muscle-tendon characteristics and function of stretch-shortening cycle performance in dancers". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2021. https://ro.ecu.edu.au/theses/2481.

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Dancers are aesthetic athletes with extraordinary skillsets defined by muscle-tendon unit (MTU) properties and stretch-shortening cycle (SSC) proficiency. Early on in athletic development, dancers are instructed to maintain aesthetic posture, wherein the hips are directly beneath the shoulders, during most jumps and leaps. Different from a countermovement jump, leaps such as the saut de chat (split leap) have been shown to cause distal shifts in torque from the hips to the ankle, likely due to postural maintenance. Thus, the role of the ankle in dance is potentially twofold as the primary joint: to both generate torque during dance-specific SSC’s and to achieve stylistic “pointing” of the toes – hyper-plantarflexion. Little research has delineated the MTU properties surrounding the ankle-joint of dancers and how they might influence dance-specific SSC performance, like saut de chat leaping. Furthermore, ankle-specific strength and conditioning tactics to simultaneously improve maximal strength capacity, MTU properties, and saut de chat leaping performance have yet to be investigated in dancers. Therefore, this thesis was founded in the following purposes: 1) to elucidate whether isolated ankle-joint SSC performance, maximal isometric and isokinetic plantarflexion strength, and maximal Achilles tendon force and elongation differ between dancers, endurance runners, and untrained controls; 2) to determine the relationship between saut de chat weighted parameter rankings, leap height, maximal voluntary isometric plantarflexion strength, medial gastrocnemius stiffness, Achilles tendon stiffness, and leaping peak power; 3) to investigate the effect of an ankle-focused block progression training program (24 sessions) on saut de chat leaping performance, maximal plantarflexion strength, and Achilles tendon stiffness. and 4) to successfully perform single fibre and fibre bundle mechanics on micro-biopsy samples from medial gastrocnemii of dancers. Study one demonstrated that dance is likely a stimulus for enhanced ankle-joint SSC function, plantarflexion isometric and isokinetic strength, and Achilles tendon elongation. Endurance running also appeared to be a possible stimulus for increased muscular strength. Study two revealed that relative peak power during leaping, maximal voluntary isometric plantarflexion strength, and medial gastrocnemius stiffness strongly and moderately predicted saut de chat performance as defined by a novel weighted parameter ranking tool. Study three showed that twelve weeks of ankle-specific block progression training appears to benefit saut de chat leaping performance, peak power output, ankle-joint kinetics, maximal strength, and Achilles tendon stiffness, while not affecting kinematic aesthetic measures. We found that by employing additional training that targets ankle-specific stretch-shortening cycle, neuromechanical, and muscle-tendon unit development, dancers are capable of improving already well-engrained movement execution strategies. Study four discovered that muscle fibre mechanics can be performed on micro-biopsy samples from medial gastrocnemius muscle, which will allow for future research on dancers’ basic muscle force-length and force-velocity properties to be more feasibly investigated.

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20

Crouzier, Marion. "Muscle coordination and musculoskeletal disorders : investigation of Achilles tendinopathy". Thesis, Nantes, 2020. http://www.theses.fr/2020NANT2013.

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Le tendon d'Achille est composé de trois sous-tendons qui proviennent chacun d'un chef du triceps surae: gastrocnemius medialis, gastrocnemius lateralis, et soleus. Une distribution non optimale de la contrainte imposée au tendon d'Achille contribuerait au développement de la tendinopathie d'Achille. D’autre part, la distribution des contraintes sur le tendon d'Achille est en partie déterminée par la distribution de la force entre les chefs des triceps surae. L'objectif général de cette thèse était d’étudier le rôle de la coordination musculaire (définie comme la distribution de force entre les muscles) dans le développement d’une tendinopathie d'Achille. Les forces musculaires de chaque muscle ont été estimées à partir de l'activation, du volume et de l'architecture musculaires. Les résultats ont montré que (i) la distribution de l’activation musculaire dans le triceps surae est robuste dans le temps, et varie considérablement d'un individu à l'autre; (ii) il existe une corrélation positive significative entre la distribution de la surface de section transversale physiologique et la distribution de l'activation au sein des gastrocnemii; (iii) le gastrocnemius lateralis contribue significativement moins à la force totale produite par le triceps sural chez les personnes atteintes de tendinopathie d'Achille par rapport aux contrôles. L’altération de la coordination musculaire pourrait être une cause, comme elle pourrait être une conséquence de la tendinopathie d’Achille
The Achilles tendon is made of three subtendons that each arises from a different head of the triceps surae: gastrocnemius medialis, gastrocnemius lateralis and soleus. Non-optimal distribution of load within Achilles tendon would contribute to the development of Achilles tendinopathy. Moreover, there is evidence that the distribution of load or strain within the Achilles tendon is partly determined by the distribution of force among the heads of the triceps surae. The overall aim of this thesis was to provide a deeper understanding of the role of muscle coordination (i.e. the distribution of force among muscles) on the development of Achilles tendinopathy. Individual muscle forces were estimated from muscle activation, volume and architecture. Results showed that (i) the distribution of activation among triceps surae is robust between days, and varies greatly between individuals; (ii) there is a significant positive correlation between the distribution of physiological cross-sectional area and the distribution of activation among gastrocnemii; (iii) muscle coordination among the triceps surae differs in people with Achilles tendinopathy compared with controls, with the gastrocnemius lateralis contributing significantly less to total triceps surae force in people with Achilles tendinopathy. Whether this altered strategy is a cause or a consequence of Achilles tendinopathy should be further explored

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21

Pamboris, George Michael. "An investigation into the mechanisms of acute effects of dynamic stretching on ankle joint mechanics and running economy". Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/16256.

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Warm-up routines commonly include stretching to increase flexibility (joint range of motion - ROM), optimise performance, and reduce the risk of injury. Literature suggests that static stretching as part of the warm-up routines decreases force and power production compared to an active warm-up or a warm-up including dynamic stretching, and therefore could be detrimental to performance. This has led to an increased interest in the use of dynamic stretching by many athletes while the benefits of such interventions and their potential mechanisms of action are not well understood. Studies presented in this thesis were conducted to examine the effects of acute dynamic stretching on aspects of performance (e.g. torque production capacity of the plantarflexors and running economy) and to identify possible neuromechanical mechanisms underpinning any potential changes. Furthermore, we attempted to examine whether altered pain tolerance/perception to stretch may be a contributing factor to the increased ROM using adaptations in the neural substrates involved by using functional magnetic resonance imaging (fMRI) technique. In the first study, both slow dynamic stretching and fast dynamic stretching increased ROM, and this was due to an increased tendon elongation. Importantly, dynamic stretching was not detrimental to the torque producing capacity of the ankle plantarflexors. Effects of dynamic stretching on the sensorimotor performance remained mainly unclear. Employment of shear wave elastography technique in the second study suggested an increase in muscle stiffness, a decrease in fascicle strain, and showed an increase in muscle thickness after dynamic stretching, supporting an increase in tendon compliance as a contributing factor to increased flexibility after dynamic stretching. In the third study, the improved running economy by dynamic stretching may be attributable to the decreased dynamic joint ankle and vertical stiffness. The fMRI study was not conclusive due to methodological issues. Present findings have practical implications for the use of dynamic stretching in sporting contexts.

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22

GAZEL, PHILIPPE. "Apport de l'imagerie par resonance magnetique en pathologie musculotendineuse traumatique du sportif". Toulouse 3, 1988. http://www.theses.fr/1988TOU31162.

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BONNETTE, GRANONE CATHERINE. "Les pasteurelloses d'inoculation et l'echographie musculo-tendineuse". Limoges, 1988. http://www.theses.fr/1988LIMO0104.

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24

Reeves, Neil David. "In vivo human skeletal muscle and tendon adaptations to increased loaing in old age". Thesis, Manchester Metropolitan University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396512.

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25

Assi, Chahine. "La hanche : anatomie morpho-fonctionnelle du complexe muscle-aponévrose-tendon. (Bases biométriques de modélisation)". Montpellier 1, 1999. http://www.theses.fr/1999MON11061.

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26

Manieu, Seguel Catalina Paz. "The role of muscle-tendon cell interaction during epithelial notum morphogenesis of Drosophila melanogaster". Tesis, Universidad de Chile, 2018. http://repositorio.uchile.cl/handle/2250/168536.

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Grado de Doctora en Ciencias biomédicas
Tissue-tissue interaction is essential to drive morphogenesis and contributing to the final shape of tissues and organs. The interaction between muscles and tendons during the establishment of the muscle-skeletal system is a great model to study this problem. During Drosophila melanogaster metamorphosis a group of cells of the dorsal thorax (notum) epithelium, specialized as tendon cells, attach to the developing Indirect Flight Muscles (IFMs). Likewise, epithelial cells anchor to the cuticle exoskeleton through apical projections. Both interactions enable the adaptation of notum epithelium to mechanical strain generated by muscle contraction, by modulating its mechanoresponse. However, scarce evidence exists about how muscle-tendon interaction contributes to the final shape of the notum. Thus, we hypothesized that the interaction between IFMs and tendon cells plays a role in notum epithelium morphogenesis. Geometric morphometric analysis of adult thorax shape shows that interfering with muscle development results in dorsal thorax deformation, however, the absence of muscles does not affect,collective-epithelial movement of the epithelium towards anterior during notum morphogenesis, suggesting that early cellular mechanisms such as cell division, rearrangements and cell delamination are not altered. Conversely, force distribution along epithelium plane changes in muscle depletion condition during notum morphogenesis, displaying anisotropic tendency in tendon-cell and midline domains. Further, impairing muscle-contraction does not affect adult thorax shape compared with wild-type conditions, indicating that muscle function as a structural support for thorax epithelium. On the other hand, the ability of notum epithelium to adapt to the mechanical strain during IFMs contraction becomes crucial to maintain the shape and integrity of the tissue. Notum epithelium lacking Chascon, a scaffold/adaptor protein involved in cytoskeleton organization upstream of Jbug/Filamin, displays epithelium deformations and impaired collective-epithelial movement during morphogenesis. Interestingly, IFMs ablation rescues backward epithelial movement associated with chascon knockdown condition, resembling wild-type phenotype, although it affects tissue-movement velocity and the ability of tendon cells to guide collective cell movement. Since notum epithelium anchors apically to the cuticle we tested whether Chascon is required for this interaction. We found that chascon knockdown in tendon cells results in epithelial detachment from the cuticle during muscles shortening stage, supporting the role of Chascon in cell adhesion and collective epithelial-cell movement. Additionally, we observed an increased anisotropy at tendon cell domains in absence of Chascon after muscle shortening, indicating the great unbalance in mechanical homeostasis after muscle pulling under this condition. Since muscle-tendon interaction is required for tendon cell differentiation in embryos we tested whether muscle was required for the expression of chascon and dumpy, a membrane protein responsible for exoskeleton-epithelium attachment, which along with Chascon is enriched in tendon cell domains during terminal differentiation. We found no significant differences in mRNA levels of chascon and dumpy, between animals lacking muscles versus wild type during muscle shortening, suggesting a muscle-independent alternative regulation of chascon and dumpy expression. Our results support the notion that Chascon is required for tension-adaptation response of notum epithelium during muscle-contraction, ensuring collective-epithelial cell movement through regulation of tendon-cell attachment to the cuticle. We suggest that Chascon, along with a multi-protein complex, regulate the mechano-response of tendon-cells during muscle contraction, by enabling collective-epithelial cell movement under mechanical load due to muscle development. Finally, these analyses will contribute to a better understanding of the role of tissue-tissue interaction in tissue morphogenesis and differentiation.

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27

Massey, Garry J. "Muscle-tendon unit morphology, architecture and stiffness in relation to strength and responses to strength training". Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/24712.

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This thesis examined the change in skeletal muscle architecture with contractile force production, the relationship of architecture with muscle strength parameters and if muscle tendinous tissue stiffness determines in vivo explosive strength (i.e. rate of torque development, RTD). Muscle and tendinous tissue adaptations to contrasting strength training regimes, and the potential capacity of these tissues to adapt following chronic strength training were also explored. Quadriceps femoris fascicle length (FL) decreased, while the pennation angle (PA) increased in a curvi-linearly manner from rest to maximal voluntary contraction (MVC) torque. Consequently, effective physiological cross-sectional area (effPCSA) during MVC was 27% greater than at rest, although effPCSA measured at rest and during MVC had similar correlations to maximal strength. In the earliest phase of contraction, FL, but not PA, was negatively related (R2=0.187) to voluntary RTD. Neither FL nor PA was related to maximal isometric or dynamic strength. Muscle-tendon unit (MTU) and patellar tendon (PT) stiffness were unrelated to voluntary and evoked RTD. Relative PT stiffness was also unrelated to relative RTD, although relative MTU stiffness was related to voluntary RTD (25-55%MVT, R2≤0.188) and evoked RTD (5-50%MVT, R2≤0.194). MTU stiffness increased after sustained-contraction (SCT, +21%), though not explosive-contraction strength training (ECT). PT stiffness increased similarly after ECT (+20%) and SCT (+16%), yet neither induced tendon hypertrophy. SCT produced modest muscle (+8%) and aponeurosis (+7%) hypertrophy. Chronic strength trained (CST: >3 years) males had substantially greater muscle and aponeurosis size, but similar tendon size as untrained controls (UNT) and short-term (12 weeks) strength trained (STT) individuals. Between these groups, at the highest common force, MTU stiffness was indifferent, while PT stiffness was similarly greater in STT and CST than UNT. These results suggest FL and PA have little influence on muscle strength and tendon stiffness has no influence on RTD. Maximum strength negated any qualitative influence of MTU stiffness on in vivo RTD. Component MTU tissues (muscle-aponeurosis vs. external tendon) adapt differentially depending on the strength training regime. Specifically, free tendon appeared to adapt to high magnitude loading, while loading duration is also an important stimulus for the muscle-aponeurosis. However, chronic strength training was not concordant with greater higher force MTU stiffness, and does not further increase higher force PT stiffness beyond the adaptations that occur after 12 weeks of strength training. Finally, no evidence was found for tendon hypertrophy in response to strength training.

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28

Sonner, Martha Jean. "Investigating Anatomical and Molecular Aspects of Proprioceptive Sensory Neuron Diversity Using a Transgenic Mouse Model". Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1420817202.

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29

Hauraix, Hugo. "Etude des interactions muscle-tendon : contribution à l'analyse des déterminants de la performance motrice explosive". Nantes, 2015. http://www.theses.fr/2015NANT3025.

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La caractérisation des propriétés intrinsèques du muscle a largement été développée sur fibre ou muscle isolé. L’avènement de l’échographie en temps réel a permis d’apprécier le comportement des faisceaux musculaires in vivo et de façon non-invasive. Les méthodes jusqu’à présent utilisées afin de caractériser les propriétés intrinsèques du muscle in vivo sont actuellement remises en question par la présence d’interactions muscle-tendon au cours de la contraction. De manière plus générale, la capacité du muscle à produire une vitesse maximale de mouvement reste peu étudiée et mal comprise dans la littérature. L’objectif de ce travail de thèse était d’évaluer les déterminants de la performance dans la production de mouvements explosifs à partir de l’échographie ultrarapide. Ce travail a été le premier à avoir rapporté une vitesse maximale de raccourcissement des faisceaux musculaires in vivo. La capacité d’un individu à produire une vitesse maximale articulaire élevée est principalement déterminée par la vitesse maximale de ses faisceaux musculaires. Malgré son influence probable, l’organisation musculo-articulaire ne semble pas nous aider à mieux appréhender la capacité à produire des vitesses de mouvement élevées. La contribution des tissus tendineux souligne l’importance des interactions muscle-tendon même lors de contractions concentriques maximales. De nouvelles connaissances sur les limites de la performance humaine ont été apportées par les différentes études menées au cours de cette thèse
The characterisation of muscular properties has been largely developed on both fiber and isolated muscle. The development of ultrasound devices has allowed to study the behaviour of the muscle fascicles in vivo and non-invasively. Nowadays the classical methods used to in vivo characterize the muscular properties are actually doubtful due to the observed muscle-tendon interactions during contractions. Globally, the muscle capacity to produce maximal shortening velocity remains unexplored and unclear. The present thesis aims to evaluate the determinants of performance in the production of explosive movements using ultrafast ultrasound. This thesis is the first work reporting the in vivo maximal shortening velocity of the fascicles. The human capacity to produce high articular velocities is mainly determined by the fascicles’ maximal shortening velocity. Despite its probable influence, the organization of musculararticular does not seem to help for a better understanding of the capacity to produce high movement velocities. The contribution of tendinous tissues highlights the importance of muscle-tendon interaction even during maximal concentric contractions. New insights about the limits of human performance were here introduced by the studies conducted during this thesis

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30

Abellaneda, Séverine. "Contribution à l'étude des modifications structurelles de l'unité myotendineuse lors d'un étirement: comparaison des méthodes de neurofacilitation et du mode de contraction excentrique". Doctoral thesis, Universite Libre de Bruxelles, 2009. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210281.

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Les étirements sont aujourd'hui une pratique courante dans les milieux sportifs et de réadaptation. Ils sont habituellement recommandés dans le but de contribuer à la prévention des blessures (Willson et al. 1991 ;Pope et al. 2000), à l’amélioration de la performance sportive lorsque celle-ci nécessite une amplitude articulaire importante (Heyters, 1985 ;Hortobagyi et al. 1985) et à la récupération de la mobilité articulaire dans le cadre d’un programme de réadaptation (Magnusson et al. 1996b). Ces méthodes, qui se sont développées ces dernières années, font classiquement appel à l’étirement passif et aux étirements neurofacilités (PNF), présentés initialement par Kabat (1958). Plus récemment, un intérêt particulier a été porté au travail musculaire excentrique. Des études ont montré que celui-ci permettait également d’augmenter l’amplitude articulaire (Willson et al. 1991 ;Nelson et Bandy, 2004).

Dans une première partie de ce travail, il nous a semblé intéressant de comparer les effets de l’étirement passif à ceux des étirements PNF par "contracté-relâché" et "contracté de l’antagoniste". Si les modalités d'application de chaque étirement sont différentes, elles présentent un intérêt majeur. De fait, elles permettent de faire varier les conditions d'allongement des différentes structures du système myotendineux, en modulant l'activité volontaire des musculatures agoniste ou antagoniste. En effet, si l’étirement passif s'effectue sans activation volontaire, l’étirement par "contracté-relâché" consiste à faire précéder l'étirement passif, d'une contraction volontaire maximale isométrique de la musculature agoniste. L’étirement par "contracté de l’antagoniste" associe à l'allongement de la musculature agoniste, une contraction volontaire maximale de la musculature antagoniste. Si de nombreuses études s'intéressent encore actuellement à caractériser leurs effets respectifs, elles ont déjà permis de montrer que ceux-ci avaient au moins deux origines distinctes, l'une neurophysiologique et l'autre mécanique (Taylor et al. 1990 ;Hutton, 1993). Au plan neurophysiologique, il est bien accepté que ces méthodes induisent une modulation de l'activité réflexe tonique facilitant le relâchement musculaire et par conséquent l’amplitude articulaire (Guissard et al. 1988 ;2001). Il est également bien admis que l’importance de ces effets sur la musculature est variable selon la méthode employée (Guissard et Duchateau, 2006). Au plan mécanique, des études menées chez l’animal ont montré que l’étirement passif modifie les caractéristiques viscoélastiques des tissus (Taylor et al. 1990), et de fait favorise l’allongement des tissus myotendineux (McHugh et al. 1992). Chez le sujet humain, plusieurs expérimentations ont montré que l’étirement par "contracté-relâché" permet d’obtenir un allongement myotendineux et un gain d’amplitude articulaire plus important que par étirement passif (Moore et Hutton, 1980). D’autres études ont montré que l’étirement par "contracté de l’antagoniste" permet de majorer encore les gains obtenus par l’étirement "contracté-relâché" (Osternig et al. 1990). Une première question posée dans ce travail est de savoir si la contribution des processus neurophysiologiques et mécaniques se traduit d’une manière spécifique sur le rapport de compliance des tissus de l’unité myotendineuse. Le développement de techniques d’investigation, telles que l’échographie, permet désormais d’observer le comportement de l’unité myotendineuse, d’une manière non invasive (Fukunaga et al. 1992 ;Herbert et Gandevia, 1995 ;Kuno et Fukunaga, 1995 ;Maganaris et al. 1998). Elle permet ainsi d’étudier les effets d’un étirement ou d’une contraction (Fukunaga et al. 1996) sur le rapport de compliance des structures musculaires et des tissus tendineux.

S’il était intéressant d’étudier la spécificité de ces trois méthodes d’étirement classiques par rapport à leurs effets sur les tissus myotendineux, il nous paraissait pertinent d’observer celle d’un travail musculaire excentrique. En effet, la particularité de celui-ci est de soumettre l’unité myotendineuse préalablement activée, à un allongement. En réadaptation, le travail excentrique est généralement proposé dans le but d’améliorer plus rapidement la symptomatologie d’une tendinopathie (Stanish et al. 1986 ;Alfredson et al. 1998). Des études récentes ont indiqué qu’il peut également être proposé pour augmenter l'amplitude articulaire (Nelson et Bandy, 2004). Toutefois, ses effets sur les tissus myotendineux ne sont pas clairement définis dans la littérature. Chez l’animal, Heinemeier et al. (2007) ont comparé les effets d’un entraînement en contractions concentriques et excentriques sur les tissus de l’unité myotendineuse. Leurs résultats indiquent que si les tissus tendineux sont sensibles aux deux modes de contraction pour leurs effets favorisant la synthèse de collagène, les structures musculaires sont spécifiquement sensibles au mode excentrique. Chez le sujet humain, Crameri et al. (2004) ont observé une série de contractions excentriques d’intensité maximale augmente la synthèse de collagène au sein de l’ensemble des tissus de l’unité myotendineuse. Ces résultats montrent que les effets de ce travail ne se limitent pas aux tissus tendineux, tels que certains protocoles thérapeutiques le suggéraient, et que le tissu musculaire doit désormais être associé à la discussion des effets de ce travail musculaire. Dans ce contexte, la deuxième question que nous avons posée est de savoir si l’étirement de l’unité myotendineuse préalablement activée, telle que se caractérise une contraction excentrique, modifie le rapport de compliance des tissus myotendineux par rapport aux méthodes classiques. Autrement dit, si l’étirement de l’unité myotendineuse activée favorise spécifiquement l’allongement de l’un des tissus de l’unité myotendineuse.

Dans une troisième partie, il nous a paru intéressant d'étudier le comportement à l’étirement de l’unité myotendineuse, dont la compliance était modifiée suite à une désadaptation à long terme. L’hypertonie spastique, qui caractérise une majorité de sujets parétiques spastiques, est généralement caractérisée par une augmentation anormale des résistances opposées à l'étirement passif (Carey et Burghart, 1993). L’origine de ces résistances peut être attribuée à des adaptations tant neurophysiologiques (Pierrot-Deseilligny et Mazières, 1985) que mécaniques et structurelles des tissus de l'unité myotendineuse (Berger et al. 1984 ;Tardieu et al. 1989). Il n’existe pourtant pas encore dans la littérature de consensus les définissant clairement (Fridén et Lieber, 2003). En outre, l’étude récente de Lieber et Fridén (2002) a mis en évidence des modifications de l’architecture des muscles fléchisseurs du carpe. Contrairement à ce qui est généralement proposé au sujet de la longueur des fascicules spastiques (Tardieu et al. 1982), Lieber et Fridén (2002) n’ont pas mis en évidence de raccourcissement de ces derniers. Ainsi, l’hypothèse de Tardieu et al. (1982), selon laquelle le raccourcissement des fascicules est à l’origine de l’augmentation des résistances à l’allongement, ne peut plus être soutenue. Il nous paraissait ainsi intéressant d’associer, à l’observation du comportement des fascicules, celui des tissus tendineux, dans le but de déterminer si l’une de ces deux structures présente des caractéristiques particulières, susceptibles d’expliquer le développement plus important de ces résistances à l’allongement. La troisième question que nous avons posée dans ce travail est de savoir comment se caractérise, à l’étirement, le rapport de compliance des tissus musculaire et tendineux dans un contexte de spasticité.

Outre le fait que la réponse à ces différentes questions soit fondamentale pour mieux comprendre et spécifier la pratique des méthodes d’étirement, l’objectif de notre travail est non seulement de mettre en évidence le tissu dont l’allongement est spécifiquement favorisé par l’une ou l’autre méthode, mais également de contribuer à différencier celui qui limite l’étirement global du système myotendineux. Dans ce contexte, il sera intéressant de pouvoir recommander la pratique d’une méthode particulière, en fonction des besoins spécifiques de chacun.

Doctorat en Sciences de la motricité
info:eu-repo/semantics/nonPublished

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31

Earp, Jacob. "The influence of external loading and speed of movement on muscle-tendon unit behaviour and its implications for training". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/533.

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In this thesis great emphasis has been placed on vastus lateralis (VL) muscle-tendon unit (MTU) structure, behaviour/movement and adaptation. Of particular interest was how external loading and movement speed influence these variables. In the first study (Chapter 3) we developed a new methodology by which electromyography (EMG) could be normalised during large range of motion knee extensions. This methodology was then used as part of a larger study, which investigated how external loading influenced the interaction of muscle and tendon (MTU behaviour) during stretch shortening cycle isoinertial knee extensions, and how muscle activity and intrinsic tendon force (Ft) influenced MTU behaviour (Chapter 4). In this study it was observed that as external loading increased the tendon strain decreased despite muscle activity and Ft increasing. It was concluded that the rapid rate of Ft development (RFDt) and speed of movement resulted in an increase in tendon stiffness that was neglected additional strain that is normally associated with increased load/force. We then investigated how external loading influenced MTU behaviour during parallel depth jump squats (JS-P), which is a more complex but also more commonly performed movement (Chapter 5). Our findings in this study contrasted those of our previous study in that we observed tendon strain increased as external loading increased. Further investigation revealed that while peak Ft increased and movement velocity decreased with increased loading intensity, the RFDt through the tendon did not significantly increase with external loading. In addition, when comparing the results from this study to those of the previous study it was found that the peak RFDt observed during heavy squat jumps was a fraction of the value observed during heavy leg extensions. These results led us to the conclusion that the RFDt that is the primary determinate of MTU behaviour and the influence of loading on MTU behaviour varies between tasks. In our next study we investigated how speed of movement influences MTU behaviour during parallel depth squatting-type movements (Chapter 6). In this study it was observed that the influence of speed of movement had on MTU behaviour differed between the eccentric and concentric phases. Specifically, it was observed that during initial tendon loading the tendon went through less strain when the movement was performed at faster speeds, however, late in the movement tendon strain increased with increased movement speed. Further investigation revealed that during initial tendon loading RFDt significantly increased with increasing movement speeds, which resulted in the viscoelastic properties of the tendon to predominate the movement. However, late in the movement when relative differences in RFDt were small the tendon behaved as a predominately elastic structure. The results from this study along with the studies prior highlighted that changing either the external load or the speed at which the load it lifted can vastly influence of the VL-MTU behaviour. In the final study of this thesis we compared the training specific structural and mechanical adaptations to slow-speed, high-load (SHL) squat training to determine how this might differ to relatively fast-speed, light-load (FLL) jump squat training (Chapter 7). In this study we observed that both groups significantly increased their strength, the cross sectional area of their quadriceps muscles, and the fascicle length of their VL. However, only subjects in the SHL group were able to increase the stiffness of their quadriceps tendon and only subjects in the FLL group increased their VL fascicle angle. It is believed that the observed training specific adaptations resulted from previously observed differences in MTU behaviour, intrinsic forces, and muscle activity observed in the previous studies. Because of this it is concluded that intentional manipulation of external load and speed of movement are viable ways to target specific muscular and tendinous adaptations. The results of this thesis has potential practical applications for designing training programs for athletes and sets the stage for further investigation into how these variables can be manipulated for prevention and rehabilitation of musculotendinous injuries.

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32

Gérus, Pauline épouse Daussant. "Modélisation biomécanique de l'interaction tendon-aponévrose-fibre pour estimer les forces musculaires : apport des mesures échographiques". Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22068/document.

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L'estimation des forces musculaires nécessite le développement d'un modèle biomécanique. Une des étapes essentielle de ce type d'approche est la modélisation de l'interaction au sein du complexe muscle-tendon entre trois composants, les fibres musculaires, l'aponévrose et le tendon par un modèle de type Hill. L'objectif de ce travail doctoral était d'identifier les paramètres dans le modèle de type Hill qui jouent un rôle important dans l'estimation des forces musculaires et de proposer une méthode pour les définir. L’échographie a été utilisée pour estimer la relation force-déformation in vivo du tendon et de l'aponévrose, et le comportement in vivo des fibres musculaires au cours de la contraction pour chaque sujet et comme un moyen de quantifier la précision des modèles en mesurant le comportement in vivo des fibres musculaires et les comparer aux sorties du modèle. L'utilisation d'une définition de l'Élément Élastique en série spécifique au sujet dans les modèles biomécaniques joue un rôle important pour des activités où les forces musculaires sont importantes. Lors de tâches isométriques maximales, la relation force-déformation du tendon spécifique au sujet combiné à des contraintes sur la géométrie initiale conduit à des estimations de forces musculaires plus faibles et un comportement différent des fibres. En ce qui concerne des activités comme le hopping et la course, l’utilisation d’une relation force-déformation du complexe tendon-aponévrose spécifique au sujet permet d’estimer des forces musculaires plus grandes et entraîne un découplage du comportement des fibres musculaires plus important par rapport au complexe muscle-tendon. Pour des activités de marche, la définition de l’élément en série dans le modèle de type-Hill n'influence pas les forces musculaires. L'échographie apparaît comme un outil intéressant pour personnaliser les modèles et pourrait être appliqué sur des patients ayant un trouble neuromusculosquelettique
The estimation of forces produced by the muscle-tendon complex around a joint needs the development of a neuromusculoskeletal model. One of essential step of this approach is the modeling by a Hill-type muscle model of the interaction within the muscle-tendon complex between three components: the muscle fiber, the aponeurosis, and the tendon. The objective of this work was to identify the parameters used as input into Hill-type muscle model that play an important role in muscle force estimation and to propose a method to define them. The ultrasonography has been used to estimate in vivo tendon and aponeurosis force-strain relationships, and the in vivo behavior of muscle fiber during the contraction for each subject. In addition, a method was proposed to quantify the model accuracy by estimating the in vivo behavior of muscle fiber and compare it with model outputs. The use of subject-specific definition of Series Elastic Element into the EMG-driven model plays an important role for activity at high level of muscle forces. During maximal isometric contraction, the subject-specific tendon force-strain relationship combined with constraint on initial muscle geometry (i.e., fiber length and muscle thickness) leads to lower estimated muscle forces and to a different behavior for the muscle fiber. Concerning highly dynamic tasks such as running and \textit{hopping}, the use of subject specific force-strain relationship for the tendon-aponeurosis complex allows to estimate higher muscle forces and leads to a heavier decoupling behavior between muscle fiber and muscle-tendon complex.The estimation of forces produced by the muscle-tendon complex needs the development of a neuromusculoskeletal model. One of essential step of this approach is the modeling by a Hill-type muscle model of the interaction within the muscle-tendon complex between three components: the muscle fiber, the aponeurosis, and the tendon. The objective of this work was to identify the parameters used as input into Hill-type muscle model that play an important role in muscle force estimation and to propose a method to define them. The ultrasonography has been used to estimate in vivo tendon and aponeurosis force-strain relationships, and the in vivo behavior of muscle fiber during the contraction for each subject. In addition, a method was proposed to quantify the model accuracy by estimating the in vivo behavior of muscle fiber and compare it with model outputs. The use of subject-specific definition of Series Elastic Element into the EMG-driven model plays an important role for activity at high level of muscle forces. During maximal isometric contraction, the subject-specific tendon force-strain relationship combined with constraint on initial muscle geometry (fiber length and muscle thickness) leads to lower estimated muscle forces and to a different behavior for the muscle fiber. Concerning highly dynamic tasks such as running and hopping, the use of subject specific force-strain relationship for the tendon-aponeurosis complex allows to estimate higher muscle forces and leads to a heavier decoupling behavior between muscle fiber and muscle-tendon complex. Concerning dynamic tasks with low force level such as walking, the estimation of muscle force was not influenced by the Series Elastic Element definition. The ultrasonography appears as a useful tool to personalize neuromusculoskeletal models and could be used for patient with neuromusculoskeletal disorders showing an alteration of tendon mechanical properties allowing to quantify the effect of rehabilitation program

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33

Barber, Lee. "Morphological and Mechanical Properties of Spastic Muscle in Children and Young Adults with Spastic Cerebral Palsy". Thesis, Griffith University, 2012. http://hdl.handle.net/10072/365221.

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Individuals with spastic cerebral palsy (CP) commonly experience muscle weakness, reduced range of motion, and increased stiffness of affected joints, which together contribute to reduced functional capacity. There is increasing awareness that muscular, in addition to neural factors, contribute to these deficits. The purposes of this thesis were to (1) develop and validate new ultrasound-based methods for assessing morphological properties of the human medial gastrocnemius (MG) muscle in vivo, and (2) to investigate the morphological and passive and active mechanical properties of the MG muscle in children and young adults with spastic CP. Validation of new methods for assessing muscle morphological properties in vivo. A freehand three-dimensional ultrasound (3DUS) approach for assessing MG muscle volume and length was developed and validated against equivalent measurements made using magnetic resonance imaging (MRI). Compared to MRI, the freehand 3DUS approach overestimated muscle volume by 1.1% and underestimated muscle belly length by 1.3%. The 3DUS approach was also found to be highly reliable. A clinical method for measurement of MG muscle and tendon length was also developed and shown to have high accuracy and reliability compared to freehand 3DUS (Appendix C). MG muscle physiological cross-sectional area (PCSA) in spastic CP. Compared to typically developed age-matched peers, PCSA of the MG muscle was reduced by 22% in young children aged 2-5 years, and by 37% in young adults aged 15-21 years. Reductions in MG muscle PCSA in the CP groups were primarily explained by a lack of volumetric muscle growth, and contribute to the muscle weakness observed in spastic CP. Passive and active MG mechanical properties in young adults with CP assessed using dynamometry. Passive ankle stiffness was 51% higher and passive MG fascicle strain was 47% lower in the spastic group CP compared to typically developed controls. These findings suggest that the increased resistance to passive ankle dorsiflexion in spastic CP is related to the inability of MG muscle fascicles to elongate with increased passive force. Compared to the typically developed group, the spastic CP group also produced 56% less active ankle plantarflexion torque across the available range of ankle joint motion, and had greater levels of antagonistic co-contraction and a longer Achilles tendon slack length. The increased Achilles tendon slack length may facilitate a greater storage and recovery of elastic energy and partially compensate for decreased force and work production by the muscles of the triceps surae during activities such as locomotion. Overall findings from this thesis indicate that the morphological and mechanical properties of the MG muscle and Achilles tendon are altered in individuals with spastic CP, and together contribute to ankle plantarflexor muscle weakness, restricted ankle dorsiflexion range and increased ankle stiffness observed in CP. Treatments for improving function in spastic CP should be directed towards the muscular as well as neural system.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Physiotherapy and Exercise Science
Griffith Health
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Wullems, Jorgen Antonin. "The influence of sedentary behaviour on muscle-tendon properties and resultant postural balance in older adults". Thesis, Manchester Metropolitan University, 2018. http://e-space.mmu.ac.uk/620938/.

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In recent years, sedentary behaviour (SB) has been identified as a health risk, independent of physical activity (PA). With the population becoming increasingly sedentary, detailed analysis of its effects is required. It is proposed that in the elderly, arguably the most sedentary age group, SB might adversely affect musculoskeletal health hence leading to poorer physical functioning, less independence and higher risk of falling. Hence, this thesis aimed to study the associations between SB and muscle-tendon properties in older adults (aged ≥60 years). To do so, a machine learning algorithm was applied onto thigh-mounted accelerometry data. Algorithm performance was acceptable for a wide spectrum of physical activity intensities, and its concurrent validity was good. Then, a cross-sectional study on 105 older adults included a 7-day habitual activity monitoring week, and assessed gastrocnemius medialis (GM) muscle-tendon morphology, architecture, function, fatigue indices, mechanical and material properties, and postural balance. From the accelerometer data, both total amount and patterns of SB were extracted. Analysis of these outcomes ranged from simple comparison of general SB levels to compositional data analysis. Multiple linear regression models showed a few associations linking SB with detrimental outcomes with GM muscle properties (dimension, strength and force). Similarly, isotemporal substitution yielded a limited number of significant potential relative effects of SB behaviour alterations. GM tendon mechanical, material and morphological properties also showed associations. Interestingly, negative associations between SB and postural balance in this group of older adults were also identified. Overall, this thesis presents novel data from detailed analyses on SB and intrinsic muscle-tendon properties in older adults. Regardless of the somewhat limited associations between sleep and PA-independent SB outcomes and GM muscle-tendon properties in older adults, the negative relationship with a task associated with habitual physical independence (i.e. postural balance) warrants further investigation of SB in elderly.

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35

Mersmann, Falk. "Effects of maturation and training on the development of the morphological and mechanical properties of the muscle-tendon unit". Doctoral thesis, Humboldt-Universität zu Berlin, Kultur-, Sozial- und Bildungswissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17667.

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Bei jugendlichen Athleten wirken sowohl die körperliche Reifung als auch die erhöhte mechanische Belastung auf die Entwicklung des Muskel- und Sehnengewebes. Die Interaktion dieser beiden adaptationswirksamen Stimuli könnte, insbesondere bei Sportlern aus Sprungdisziplinen, Dysbalancen des Kraftpotenzials der Muskulatur und der Widerstandsfähigkeit der Sehne auslösen und somit potentiell das Verletzungsrisiko der Sehne erhöhen. Vor diesem Hintergrund untersucht die vorliegende Arbeit mittels Magnetresonanztomographie, Ultraschall und Dynamometrie die Entwicklung der morphologischen und mechanischen Eigenschaften der Knieextensoren und der Patellarsehne bei jugendlichen Kader-Volleyballathleten. Durch eine Querschnitts- und zwei Längsschnittstudien konnte Evidenz dafür erbracht werden, dass sich unter dem Einfluss der sportartspezifischen Belastung Kraft und Morphologie des Muskels in Relation zu den mechano-morphologischen Eigenschaften der Patellarsehne bei den jugendlichen Athleten nicht ausgewogen entwickeln, was zu einer erhöhten chronischen Belastung und Beanspruchung des Sehnengewebes führt. Darüber hinaus können muskulotendinöse Dysbalancen im Trainingsprozess durch erhöhte Fluktuationen der Muskelkraft und einer nicht-adäquaten Modulation der Widerstandsfähigkeit der Sehne zu episodischen Spitzen der mechanischen Beanspruchung der Sehne führen. Eine derart unausgewogene Entwicklung von Muskel und Sehne könnte für die Ausprägung von Überlastungsbeschwerden in der hier untersuchten Risikogruppe für Tendinopathien prädisponieren. Im Rahmen der Forschungsbemühungen wurde darüber hinaus ein Verfahren zur Vorhersage des Volumens von Oberschenkelmuskeln auf der Basis einfach zu erhebender Parameter entwickelt. Durch das Verfahren ließe sich zukünftig der Zeit- und Kostenaufwand muskelmorphologischer Diagnostik deutlich reduzieren.
In adolescent athletes, the development of muscle and tendon tissue is influenced both by maturation and mechanical loading. The interaction of these two driving stimuli could initiate imbalances in the development of the muscle strength capacity and tendon stiffness, especially in athletes from sports that feature a high frequency of jumps. A consequence could be an increased mechanical demand placed upon the tendon by the working muscle, which might increase the risk of tendon injury. Considering the lack of information on the effects of maturation and superimposed mechanical loading on the muscle-tendon unit during adolescence, the present work examines the development of the morphological and mechanical properties of the knee extensors and patellar tendon in adolescent elite volleyball athletes by means of magnetic resonance imaging, ultrasound and dynamometry. A cross-sectional comparison and two longitudinal studies provided evidence that the two-fold stimulus of sport-specific loading and maturation results in and imbalanced development of muscle strength and morphology in relation to the mechano-morphological properties of the patellar tendon in mid-adolescent volleyball athletes and results in increased tendon stress and strain. Moreover, during a training process, fluctuations of muscle strength and an inadequate modulation of tendon stiffness initiate episodes of high-level tendon strain during maximum muscle contractions. Such an imbalanced development of muscle and tendon could predispose for the development of tendon overuse injury in adolescent volleyball athletes, which are known to be at high risk of developing tendinopathy. Moreover, in the context of the described research endeavour, a method for the volume prediction of thigh muscles on the basis of easily measurable parameters has been developed, which could greatly reduce the time and costs involved in the diagnostics of muscle morphology in the future.

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King, Stephanie Louise. "Adaptations in plantarflexor muscle-tendon properties and their impact on gait in claudicants with peripheral arterial disease". Thesis, University of Hull, 2015. http://hydra.hull.ac.uk/resources/hull:13627.

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Peripheral arterial disease (PAD) is a chronic atherosclerotic disease, primarily affecting the lower limbs. The associated intermittent claudication (IC) is a muscle pain/cramping sensation in the legs, primarily brought on by physical activity, such as walking, which can negatively affect daily function and quality of life. Poorer levels of lower-limb muscle strength are strong predictors for mortality and the plantarflexor muscles in particular are a frequent site of claudication pain, with previous literature also indicating their dysfunction during level gait. However, little is known about the size and architecture of these muscles, the quality of the in-series Achilles tendon or the factors that contribute to voluntary joint moments and how these relate to physical function in this population. The aim of this thesis was to determine the functional properties of the gastrocnemii muscles and Achilles tendon in order to make evidence-based clinical recommendations for specific exercise interventions for claudicants. A total of 23 participants (13 claudicants and 10 controls) took part in the study. Muscle-tendon dimensions and architecture, tendon properties, activation patterns and muscle strength, power and quality (specific tension) were assessed be integrating ultrasound imaging, electromyography and dynamometry. Stair gait biomechanics were analysed using 3D motion capture as indicators of whole body physical function. Within the claudicant cohort, disease severity was determined using the ankle brachial pressure index and walking performance assessed by a modified six-minute walk test. Average post-exercise ankle brachial pressure index of the claudicating-limbs were 0.55±0.21 with initial (onset of claudication pain) and absolute (maximal claudication pain) walking distances of 105±45m and 265±136m, respectively. The first study investigated the relationships between the resting architecture of the gastrocnemii and functional properties of the Achilles tendon with disease severity and walking endurance. Worse disease severity was significantly associated with longer fascicle: tendon length ratios in both lateral (R=-.789, P=.001) and medial (R = -.828, P = < .001) gastrocnemius, and increased tendon hysteresis (R=-.740, P=.006). This suggests that the Achilles tendon has undergone deleterious changes and the muscle has adopted a structure designed to compensate for this. However, the concomitant associations with poorer walking endurance indicate this mechanism is not effective. Walking endurance could also be explained by lateral and medial gastrocnemius pennation angle, maximum tendon force, tendon hysteresis and disease severity (R2=~0.6). The direction of coefficients within these models suggests that improving tendon properties and increasing strength, but without increasing pennation angle, would be beneficial for walking endurance. Thus, eccentric resistance training may be an effective exercise intervention. The second study investigated relationships between static and dynamic muscle quality with disease severity and walking endurance. The power-producing capabilities of claudicants’ plantarflexors (both the claudicating/painful limb and asymptomatic limb) were impaired compared to healthy controls, particularly at high contraction velocities (24% difference at 180°/s). This could be explained by some reduction in gastrocnemii muscle quality and a greater reliance on the prominently type I fibred soleus muscle. As reduced dynamic capability of the plantarflexor muscles was associated with disease severity (R=.541, P=.037) and walking endurance (R=.689, P=.006), high velocity resistance training of the plantarflexor muscles appears important to maintain functional performance. The third and fourth studies investigated the functionally challenging daily tasks of stair ascent and stair descent, respectively. During stair ascent, plantarflexor moments were similar in claudicants compared to healthy controls, indicating the muscle could meet the strength demands of this task. We also observed that ankle angular velocity at the instant of peak moment, peak ankle power generation, as well as propulsive and vertical forces, were all reduced during forward continuance in the claudicating-limb group. It seems that claudicants possess adequate levels of strength when moving more slowly but are unable to remain strong when moving more quickly, therefore it could be suggested that the slower walking speed is a means to allow claudicants to operate within safer limits relative to their maximal strength capacity. This provides further evidence, in a functional context, of the velocity-dependent limitations of the plantarflexors detected in study two. During stair descent we hypothesised that the task demands would be redistributed away from the affected plantarflexors towards the muscles surrounding the hips and knees. Instead, the claudicants placed a greater reliance on the plantarflexors compared to healthy controls (40% vs 28% of plantarflexor contribution to peak support moment). Additionally, a unique hip extensor strategy was exposed during weight acceptance that was adopted by 73% of the claudicating-limb group, which was also associated with increased disease severity. However this was not a mechanism to reduce the functional demands on the plantarflexors but rather to reduce demands on the knee musculature. These data indicate the claudicants were relying heavily on the functionally limited plantarflexors to absorb the falling body mass during weight acceptance in stair descent, which may pose an increased risk of falling. This thesis has identified important changes in the structure and quality of the gastrocnemii muscles and the properties and function of the Achilles tendon, that appear to influence whole body function during demanding and risky physical activities (stair negotiation) that necessitate alternate strategies. Taken as a whole, it is clear that high-velocity and eccentric resistance training would likely improve the musculoskeletal characteristics of claudicants, increase walking endurance and facilitate safe stair negotiation.

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Jabbar, Shaima Ibraheem. "Automated analysis of ultrasound imaging of muscle and tendon in the upper limb using artificial intelligence methods". Thesis, Keele University, 2018. http://eprints.keele.ac.uk/5433/.

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Accurate estimation of geometric musculoskeletal parameters from medical imaging has a number of applications in healthcare analysis and modelling. In vivo measurement of key morphological parameters of an individual’s upper limb opens up a new era for the construction of subject-specific models of the shoulder and arm. These models could be used to aid diagnosis of musculoskeletal problems, predict the effects of interventions and assist in the design and development of medical devices. However, these parameters are difficult to evaluate in vivo due to the complicated and inaccessible nature of structures such as muscles and tendons. Ultrasound, as a non-invasive and low-cost imaging technique, has been used in the manual evaluation of parameters such as muscle fibre length, cross sectional area and tendon length. However, the evaluation of ultrasound images depends heavily on the expertise of the operator and is time-consuming. Basing parameter estimation on the properties of the image itself and reducing the reliance on the skill of the operator would allow for automation of the process, speeding up parameter estimation and reducing bias in the final outcome. Key barriers to automation are the presence of speckle noise in the images and low image contrast. This hinders the effectiveness of traditional edge detection and segmentation methods necessary for parameter estimation. Therefore, addressing these limitations is considered pivotal to progress in this area. The aims of this thesis were therefore to develop new methods for the automatic evaluation of these geometric parameters of the upper extremity, and to compare these with manual evaluations. This was done by addressing all stages of the image processing pipeline, and introducing new methods based on artificial intelligence. Speckle noise of musculoskeletal ultrasound images was reduced by successfully applying local adaptive median filtering and anisotropic diffusion filtering. Furthermore, low contrast of the ultrasound image and video was enhanced by developing a new method based on local fuzzy contrast enhancement. Both steps contributed to improving the quality of musculoskeletal ultrasound images to improve the effectiveness of edge detection methods. Subsequently, a new edge detection method based on the fuzzy inference system was developed to outline the necessary details of the musculoskeletal ultrasound images after image enhancement. This step allowed automated segmentation to be used to estimate the morphological parameters of muscles and tendons in the upper extremity. Finally, the automatically estimated geometric parameters, including the thickness and pennation angle of triceps muscle and the cross-sectional area and circumference of the flexor pollicis longus tendon were compared with manually taken measurements from the same ultrasound images. The results show successful performance of the novel methods in the sample population for the muscles and tendons chosen. A larger dataset would help to make the developed methods more robust and more widely applicable. Future work should concentrate on using the developed methods of this thesis to evaluate other geometric parameters of the upper and lower extremities such as automatic evaluation of the muscle fascicle length.

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38

Dimitriou, Michael. "Discharges in human muscle afferents during manual tasks". Doctoral thesis, Umeå universitet, Integrativ medicinsk biologi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1961.

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Muscle spindles are complex sensory organs that have been strongly implicated in the control and perception of movements. Human muscle spindles in relaxed muscles behave as stretch receptors, responding to the length and velocity of their parent muscles. However, it has been unclear how they discharge during active movements since their discharges are also affected by fusimotor activity and extrafusal contractions. The vast majority of neurophysiological recordings of muscle afferents have been obtained under passive conditions, or active but behaviourally restricted conditions. These restrictions prevent predictions of human muscle afferent activity during purposeful multi-joint movements, naturally occurring during tasks such as hand shaping, grasping or key-pressing. An experimental protocol was therefore developed which allowed recordings of muscle receptor afferent activity using microneurography during unrestrained wrist and digit movements. Along with single afferent discharges, recordings were obtained of electromyographic activity of major forearm muscles and the kinematics of the wrist and digits. This approach allowed investigations of the factors shaping afferent discharge during everyday manual tasks, i.e., block-grasping and pressing sequences of keys, and during active sinusoidal joint movements. The afferents’ ability to encode information concerning the state of the muscle and joint kinematics during these tasks was also assessed. The responses of spindle afferents from load-bearing muscles were approximatelly 90 degrees more phase-advanced than expected on the length of their parent muscles. That is, the discharges of primary muscle spindle afferents were significantly affected by both velocity and acceleration, the discharges of secondary afferents by velocity, and neither afferent type was particularly affected by static muscle length. Accordingly, these afferents failed to encode length, encoded velocity well and acceleration poorly. The representation of muscle length and velocity was, however, significantly improved when the discharge activity of Golgi tendon afferents was taken into consideration along with muscle spindle activity. The discharge of primary afferents during both key-pressing and block-grasping was best correlated to the muscle velocities observed ~100-160 ms in the future. This predictive ability went beyond what could be expected from the spindles’ simultaneous sensitivity to velocity and acceleration, and could thus only be explained by implicating the fusimotor drive. In addition, evidence is presented that the fusimotor control of spindles was contingent on entire movement sequences during the key-pressing task. It is proposed that the phase relationship between the discharge rate of spindle afferents and the length of their parent muscles is load dependent. Moreover, muscle spindles seem to act as forward sensory models of their parent muscle, which makes sensorial feedback control possible despite neural delays.

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39

Penailillo, Luis. "Muscle damage and metabolic profiles of eccentric cycling". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/706.

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Eccentric cycling, in which the knee extensor muscles perform eccentric contractions while trying to brake the backward rotational movements of the cranks of a cycle ergometer, has been shown to effectively increase muscle function and volume with a low metabolic cost. However, acute responses to repeated eccentric cycling bouts have not been well documented. Thus, the primary purposes of this PhD project were to investigate muscle damage and metabolic profiles of eccentric cycling in comparison to concentric cycling (Studies 1-3), and muscle-tendon behaviour (Study 4) during eccentric cycling in relation to muscle damage. Study 1 compared muscle damage and metabolic profiles between a bout of concentric cycling (CONC) and two bouts of eccentric cycling (ECC1, ECC2) performed by 10 healthy men (28 ± 8 y), with a 2-wk interval between bouts. All cycling bouts were performed for 30 min at 60% of CONC maximal power output (POmax). Heart rate (HR), oxygen consumption, blood lactate (BLa) and rate of perceived exertion were 19-65% lower during ECC1 than CONC, and HR and BLa were 12-35% lower during ECC2 than ECC1. Exercise-induced decreases in knee extensor maximal voluntary contraction (MVC) torque and vertical jump height as well as increases in muscle soreness were significantly greater after ECC1 than CONC and ECC2, and no significant changes in these variables were found one day after CONC and ECC2. It was concluded that eccentric cycling was less metabolically demanding than CONC, and muscle damage was minimal after the second eccentric cycling bout. Study 2 examined fat and carbohydrate utilisation during and immediately after cycling, and resting energy expenditure before and both 2 and 4 days post-cycling using indirect calorimetry. An oral glucose tolerance test was performed before, and 1 and 3 days post-cycling. Fat utilisation was greater during ECC1 (72%) and ECC2 (85%) than CONC, and was 48% greater during ECC2 than ECC1. Post-exercise energy expenditure and fat utilisation were less after ECC1 than CONC (30% and 52%, respectively), but similar between CONC and ECC2. Glucose uptake increased 3 days post-ECC1. These results suggest greater fat utilisation during and after eccentric than concentric cycling without glucose uptake impairment. Study 3 tested the hypothesis that rate of force development (RFD) would be a more sensitive marker of muscle damage than MVC torque by comparing the changes in MVC torque and RFD after CONC, ECC1 and ECC2. Decreases in MVC torque were significantly greater immediately and 1-2 days after ECC1 than CONC and ECC2. RFD decreased immediately after all cycling bouts, but RFD measured in the interval 100-200 ms (RFD100-200) decreased at all time points after ECC1 (24-32%) as well as immediately after ECC2 (23%), but did not change after CONC. The magnitude of decrease in RFD100-200 after ECC1 was 7-19% greater than MVC torque. These suggest that RFD100-200 is a more specific and sensitive marker of eccentric exercise-induced muscle damage than MVC torque. To investigate the mechanisms underpinning the repeated bout effect in eccentric cycling, Study 4 examined the hypothesis that vastus lateralis muscle-tendon behaviour would be different between two (i.e. repeated) eccentric cycling bouts. Eleven healthy men (27.1 ± 7.0 y) performed 10 min of eccentric cycling at 65% of CONC POmax twice (ECC1, ECC2) separated by 2 weeks. Greater muscle soreness was developed 1-2 days after ECC1 than ECC2. Electromyogram and crank torque were similar between bouts, but the magnitude of fascicle elongation during ECC2 was 16% smaller than ECC1. These results suggest that smaller elongation of fascicles was associated with less muscle soreness after ECC2, and possibly the repeated bout effect. These studies revealed the muscle damage profile of eccentric cycling, one of the potential mechanisms of the repeated bout effect, and metabolic characteristics of repeated eccentric cycling bouts. Since muscle damage is minimal and can be abolished by proper prescription, eccentric cycling may be an ideal exercise for elderly and frail individuals with impaired muscle oxidative function (e.g. diabetes and chronic obstructive pulmonary disease). Further studies are warranted in these populations.

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40

AMBROS, DOMINIQUE. "Kyste synovial plantaire de la gaine du tendon du muscle long flechisseur propre du gros orteil : a propos de deux observations, revue de la litterature". Reims, 1988. http://www.theses.fr/1988REIMM011.

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41

Johnson, Shelley. "Biomechanical analysis of a 'heavy-load eccentric calf muscle' rehabilitation exercise in persons with Achilles tendinosis a dissertation submitted to Auckland University of Technology in partial fulfilment of the requirements for the degree of Master of Health Science (MHSc), 2008 /". Click here to access this resource online Click here to access this resource online, 2008. http://aut.researchgateway.ac.nz/handle/10292/536.

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Fontana, Heiliane de Brito. "In-vivo vastus lateralis force-length and force-velocity relationships at the fascicle and muscle tendon unit level". Universidade do Estado de Santa Catarina, 2015. http://tede.udesc.br/handle/handle/643.

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Embora as relações força-comprimento (F-C) e força-velocidade (F-V) de um músculo possam ser facilmente determinadas in-vitro, a determinação in-vivo é certamente mais complexa, e baseia-se frequentemente em medidas de torque e ângulo articular. Uma importante limitação dessa abordagem reside no fato de as mudanças de comprimento do fascículo muscular não se relacionarem de maneira simples às da unidade músculo-tendínea (UMT). Dessa forma, a investigação in-vivo da mecânica músculo-tendão torna-se necessária para a determinação da expressão dessas propriedades musculares no contexto do movimento humano. Neste trabalho, foi determinado, in-vivo, a relação F-C (Parte I) e a relação F-V (Parte II) nos níveis do fascículo e da UMT para contrações voluntárias do músculo vasto lateral (VL) em humanos. A relação F-C foi obtida para contrações máximas e submáximas e a relação F-V, para diferentes níveis de pré-contração do músculo. A fim de obter um melhor entendimento do fenômeno, o movimento de extensão de joelho foi analisado em diferentes amplitudes de acordo com características cinéticas e cinemáticas do mesmo. As coletas de dados envolveram medições sincronizadas de torque e ângulo de joelho, bem como arquitetura muscular e EMG do VL durante contrações isométricas (F-C) e isocinéticas (F-V) de extensores de joelho. Na Parte I, foi demonstrado que a quantidade de encurtamento dos fascículos em uma contração isométrica depende do comprimento da UMT/ ângulo articular, resultando em diferentes formatos para a relação F-C entre os níveis do fascículo e da UMT e entre contrações máximas e submáximas. As relações F-C para contrações submáximas foram determinadas a partir de níveis percentuais de força (como sugerido na literatura), mas, também, através de uma nova abordagem baseada em níveis percentuais de ativação (EMG). Com base na primeira abordagem, por definição, os picos de força para as relações F-C ocorrem em um comprimento muscular fixo, mas, devido a complacência da UMT, em comprimentos de fascículo maiores a medida que a força na UMT decresce. Contrariamente, na análise baseada em ativação, os picos de força ocorrem em um comprimento de fascículo constante, mas em comprimentos musculares menores a medida que a a força na UMT decresce. Este resultado sugere que o maior potencial de geração de força submáxima é obtido em comprimento de fascículo próximo ao definido como ótimo, ou seja, no comprimento onde a sobreposição dos miofilamentos é máxima. Na Parte II dessa tese, a análise da relação F-V evidenciou que a velocidade de encurtamento do fascículo durante a extensão isocinética de joelho pode ser menor, semelhante ou maior do que a da UMT dependendo da velocidade articular e de qual parte do movimento é analisada. A velocidade de encurtamento da UMT aumenta sistematicamente com a velocidade articular, enquanto que os fascículos podem permanecer com velocidades constantes para uma grande amplitude de velocidade articular. Os resultados apontam para a crítica natureza da interação entre ângulo articular, força/ativação muscular, elementos elásticos e mecânica dos fascículos musculares e auxiliam na superação das restrições encontradas quando se relaciona e se aplica conhecimento obtido nos diferentes níveis organizacionais dos músculos.
Although there are no major difficulties in obtaining the force-length (F-L) and force-velocity (F-V) relationships in skeletal muscles in-vitro, obtaining them in-vivo is certainly much more complex, and is often based on joint torque and angle. A primary problem is that fascicle length changes are not associated in a simple manner with changes in the length of the whole muscle-tendon unit (MTU). Therefore, investigation on whole muscle tendon mechanics in-vivo is needed in order to elucidate the link between these mechanical properties and the muscle performance in the context of human movement. In this thesis work, we determined the in-vivo F-L relationship (Part I) and F-V relationship (Part II) at the fascicle and MTU levels for voluntary contractions of the human vastus lateralis muscle (VL). F-L relationships were obtained for maximal and submaximal contractions, and F-V relationships for different pre-load conditions. In order to obtain a better understanding of the phenomena, different ranges of the knee extension movement were identified for their kinematic or kinetic properties and were analyzed separately. Data collection involved synchronized measurements of knee extensor torque, knee angle, VL EMG and muscle architecture (fascicle length and pennation angle) during isometric (F-L) and isokinetic (F-V) knee extensor contractions. In Part I, we demonstrated that fascicles undergo different amounts of shortening depending on MTU length/ joint angle, which results in different shapes of the fascicle and muscle F-L relationship, and produces different F-L shapes for maximal and submaximal levels of activation. The submaximal fascicle F-L relationships were determined based on percentages of force (as typically done in the literature), but novel to the literature, also based on percentages of activation (EMG). In the force-based analysis, the peak forces of F-L relationships, by definition, must occur at the same muscle length, but because of muscle-tendon compliance, it occurs at increasing fascicle lengths with decreasing levels of force. In contrast, in the activation-based analysis, the peak occurred at similar fascicle lengths, but because of muscle compliance, at decreasing muscle lengths with decreasing levels of force. This result suggests that, in the activation-based analysis, the greatest force generating potential always occurs close to optimal fascicle lengths; that is the length at which sarcomeres present maximum myofilament overlap. In Part II, analysis of the F-V relationship showed that fascicle shortening velocities during maximum isokinetic knee extension exercises can be slower, equal or faster than the corresponding MTU shortening velocities, depending on the knee extensor speed and depending on which part of the knee extension curve is analyzed. MTU shortening velocities increase systematically with increasing speeds of knee extension. However, this observation is not made for fascicle shortening velocities, which, depending on the range and conditions analyzed, remain about constant across a large range of knee extensor speeds. The results of this thesis point to the critical nature of the interaction between joint angle, muscle force/activation, series elastic compliance, and fascicle mechanics and help to overcome the difficulties in relating and applying knowledge obtained at the different organizational levels of muscles.

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43

Stafilidis, Sawas [Verfasser]. "Sprint performance in relation to mechanical properties of the muscle-tendon unit and running track compliance / Sawas Stafilidis". Köln : Zentralbibliothek der Deutschen Sporthochschule, 2006. http://d-nb.info/1071871706/34.

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44

Kay, Anthony D. "Impact of static stretch and muscular contractions on force production within the human triceps surae muscle-tendon complex". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2010. https://ro.ecu.edu.au/theses/123.

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Pre-performance routines commonly include stretching and intense muscular contractions in an attempt to optimise muscular performance and reduce injury risk. However, the isolated and combined effects of stretching and muscle contractions on neuromuscular performance are not well described. The aims of this research were to examine the effects of acute static stretch and intense muscular contractions on force production of the human plantarflexors and to examine possible mechanical and neuromuscular mechanisms underpinning any changes. Techniques including isokinetic dynamometry, electromyography (EMG), sonography and motion analysis were used in three studies on recreationally active human volunteers (n=20). In the first study, three 60-s passive stretches was found to significantly reduce concentric plantarflexor joint moment (5.0%; P<0.05), which was correlated (r = 0.81; P<0.01) with a reduction in EMG amplitude (9.2%; P<0.05). No reduction in Achilles tendon stiffness or gastrocnemius medialis (GM) muscle operating length was found, and all measures recovered by 30 min. This indicates that post-stretch force losses are transient and are largely associated with reduced neuromuscular activity (EMG amplitude) rather than changes in the muscles’ operating lengths. Nonetheless, strong muscular contractions, commonly performed during preperformance routines and incorporated into research designs, may influence the effects of stretch. In the second study it was found that six 8-s maximal isometric contractions reduced Achilles tendon stiffness (10.9%; P<0.01) and passive joint moment (4.9%; P<0.01) and also significantly reduced concentric moment (11.5%; P<0.01), which was again correlated (r = 0.90; P<0.01) with a reduction in EMG amplitude (21.0%; P<0.01). Importantly, a subsequent bout of static stretch, which was identical to that used in study 1, did not result in a further change in any measure (P > 0.05). Whilst concentric moment and EMG recovered 30 min later, the decreases in Achilles tendon stiffness and passive moment remained. Thus, the normal stretch-induced reductions in force production were removed when isometric contractions were performed prior to stretch, but this was because concentric strength and neuromuscular activity were already affected; the reduction in concentric moment without a decrease in isometric moment indicates a contraction mode-specific response. The final study revealed that the use of concentric contractions (6×8-s) also resulted in similar reductions in Achilles tendon stiffness (11.7%; P<0.01) and concentric joint moment (6.6%; P<0.01) as the isometric contractions, and these were correlated (r = 0.94; P<0.01) with a reduction in EMG amplitude (10.2%; P<0.01). However, a further reduction in concentric moment was detected following an identical bout of static stretch (5.8%; P<0.01) with no further change in EMG. Importantly, EMG recovered 30 min later while concentric moment remained depressed (9.2%; P<0.01), indicating a musclebased mechanism for these force losses. No reduction in GM muscle operating length was found, removing this as a mechanism underpinning the losses in force. The findings from the present series of studies have important implications for research study design as the warm-up imposed on subjects prior to stretch seems to strongly influence the impact of stretch. Furthermore, the results also have important practical implications in the formulation of preperformance routines where maximal force production in the plantarflexors is an important goal.

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45

Edin, Benoni B. "Classification of muscle stretch receptor afferents in humans". Doctoral thesis, Umeå universitet, Fysiologi, 1988. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-101350.

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The response patterns of human stretch receptors in the finger extensor muscles of the forearm were studied using the microneurography technique. Single-unit recordings were obtained from one-hundred and twenty-four afferents. A procedure was developed to classify the units in muscle spindle primary afferents, secondary afferents, and Golgi tendong organ afferents. The procedure allows an objective and reproducible classification on the basis of the afferents’ responses to a series of tests which individually are non-conclusive. It was demonstrated that maximal twitch contractions can be elicited in the finger extensor muscles of the forearm, without causing undue discomfort to the subjects, or hazarding the single-unit recording. The response of the units to this test allowed, in most cases but not always, a separation in muscle spindle and tendon organ afferents. Thus the test was not adequate for an unequivocal classification. Three discrete response parameters were extracted from ramp-and-hold stretches, viz. the presence or absence of an initial burst and a deceleration response, and prompt silencing at slow muscle shortening. The distributions of the parameters were significantly different among the three unit types. These parameters which were pair-wise independent constituted a set of considerable discriminative power. It was shown that human muscle spindles have about the same static position sensitivity to fractional muscle stretch as previously found in animals. Stretch sensitization was demonstrated by rapid, repeated stretches of the muscle which enhanced the réponse to subsequent slow stretches of muscle spindles. Sensitization was different with primary and secondary muscle spindle afferents whereas Golgi tendon organ afferents never displayed stretch sensitization. One-to-one driving with small-amplitude sinusoidal stretches superimposed on ramp-and- hold stretches was almost exclusively seen with primary muscle spindle afferents, whereas secondaries seldom and tendon organ afferents never displayed driving. The afferent responses during slowly increasing isometric contractions and rapid relaxations were analysed. An increased discharge rate on relaxation was common among spindle afferents whereas it was never seen in tendon organs afferents. Two separate groups of spindles afferents were found with regard to fusimotor recruitment. The largest group was recruited at rather low and variable contractile forces whereas the smaller group was not recruited at all. The proportions of the three unit types, spindle primary, spindle secondary, and Golgi tendon organ afferents were estimated from a preliminary classification and the distribution of the eight response features were analyzed for each class of afferents. On the basis of these estimates and the response pattern of the individual unit Bayes’ theorem was used to calculate the probabilities that the unit was a spindle primary, a spindle secondary, or a tendon organ afferent. Estimates indicate that about 19 out of 20 muscle afferents are correctly classified when all eight features are analyzed.

Diss. (sammanfattning) Umeå : Umeå universitet, 1988, härtill 6 uppsatser.

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46

Borges, Mariana de Oliveira. "Mudança nas propriedades passivas da unidade musculo-tendínea do tríceps sural durante 10 minutos de alongamento estático passivo". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/181842.

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Introdução: os estudos sobre flexibilidade vêm tentando compreender quais propriedades explicam o aumento da amplitude de movimento (ADM), além do aumento de extensibilidade muscular. Propriedades mecânicas passivas de outros tipos de tecido, como o tendão, vêm sendo avaliadas, para entender a sua interferência no aumento da ADM. Desenho do estudo: o estudo foi do tipo ensaio clínico randomizado. Objetivos: analisar, minuto a minuto, o deslocamento da junção miotendínea (JMT) do músculo gastrocnêmio medial com o tendão do calcâneo e o torque passivo durante uma sessão de 10 minutos de alongamento estático passivo de flexores plantares, e analisar a mudança destas e de outras propriedades passivas mecânicas da unidade músculo-tendínea (UMT) do tríceps sural antes e após essa intervenção, verificando se estas mudanças perduram após 15, 30, 45 e 60 minutos após o protocolo de alongamento. Métodos: 30 participantes saudáveis foram divididos em grupo controle, o qual permaneceu em repouso, e experimental, o qual realizou uma sessão de 10 minutos de alongamento estático passivo no dinamômetro isocinético. Os participantes realizaram os testes de ADM, torque passivo, deslocamento da JMT e histerese antes e após a intervenção (0, 15, 30, 45 e 60 minutos). A partir dessas variáveis, foram calculadas as medidas de rigidez tendínea, muscular e da UMT. Resultados: Cinco participantes não permaneceram relaxados durante os testes e foram excluídos após análise dos dados eletromiográficos. 25 participantes foram incluídos na análise. Os resultados foram divididos em dois estudos diferentes. No primeiro estudo, apenas os 12 participantes do grupo experimental foram incluídos e, ao longo da intervenção, foi encontrada uma redução significativa do torque passivo, com a principal diferença ocorrendo nos minutos cinco e sete. No segundo estudo, foram comparados os indivíduos do grupo controle (n=13) e do grupo experimental (n=12), com um período de follow up de 60 minutos após a intervenção. A ADM aumentou e permaneceu aumentada até uma hora após a intervenção em ambos os grupos. As variáveis de deslocamento da JMT, rigidez muscular e histerese aumentaram em alguns momentos ao longo do tempo, sem diferença entre os grupos. A rigidez tendínea não apresentou diferença nem para grupo e nem para tempo. As variáveis de torque passivo e rigidez da UMT apresentaram uma interação significativa entre grupo e tempo, com uma redução das duas ao longo do tempo no grupo experimental. Conclusões: há uma redução de torque passivo ao longo de uma sessão de alongamento estático de 10 minutos dos flexores plantares de tornozelo, e fazer parte do grupo experimental influenciou no comportamento do torque passivo e da rigidez da UMT, levando a uma maior redução das mesmas para o grupo que realizou o alongamento. A ADM aumentou e permaneceu aumentada até uma hora após a intervenção.
Background: studies on flexibility have attempted to understand which properties explain increased range of motion (ROM), in addition to increased muscle extensibility. Mechanical and passive properties of other types of tissue, such tendon tissue, have been evaluated in order to understand their interference in increased ROM. Study Design: randomized clinical trial. Objectives: to analyze, minute by minute, myotendinous junction (MTJ) displacement of the medial gastrocnemius muscle with Achilles tendon and passive torque during a 10-minute passive static stretching of the ankle plantar flexors. To analyze, also, the time course change of these and other muscle-tendon unit (MTU) mechanical properties of the triceps surae before and after the intervention, verifying if the changes persist after 15, 30, 45 and 60 minutes after the stretching protocol. Methods: 30 healthy participants were divided into a control group, which remained at rest, and an experimental group, which performed a 10-minute passive static stretching on the isokinetic dynamometer. Participants performed tests of ROM, passive torque, MTJ displacement and hysteresis before and after the intervention (0, 15, 30, 45 and 60 minutes). From these variables, the measures of tendinous, muscular and MTU stiffness were calculated. Results: Five participants did not remain relaxed during the test and were excluded after electromyographic data analysis. 25 participants were included in the analysis. Results were divided into two different studies. In the first one, only 12 participants of experimental group were included and during the intervention, a significant reduction of the passive torque was found, with the main difference occurring in minutes five and seven. In the second study, individuals from control group (n=13) and experimental group (n=12) were compared, with a 60 minute follow-up period after the intervention. ADM increased and remained increased up to one hour after the intervention. The variables of MTJ displacement, muscular stiffness and hysteresis increased at some moments over time, with no difference between the groups. The tendinous stiffness showed no difference neither for group nor for time. The variables of passive torque and MTU stiffness showed a significant interaction between group and time, with a reduction of the two over time in the experimental group. Conclusions: passive torque decreased throughout a 10-minute passive static stretching of the ankle plantar flexors, and being part of the experimental group influenced the behavior of the passive torque and the MTU stiffness, leading to a greater reduction of the same for the group who performed the stretching.

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47

Konrath, Jason Matthew. "A Morphological and Biomechanical Evaluation of the Semitendinosus and Gracilis After the Use of Hamstring Tendon for Anterior Cruciate Ligament Reconstruction". Thesis, Griffith University, 2017. http://hdl.handle.net/10072/368183.

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Injuries to the anterior cruciate ligament (ACL) are one of the most common knee injuries, with the majority occurring during non-contact manoeuvers such as side-stepping and single leg landing. Surgical intervention is generally required to restore stability to the tibiofemoral joint, unfortunately no perfect graft choice exists for reconstruction of the ACL, with all graft choices having potential advantages and disadvantages. The quadrupled hamstring autograft taken from the semitendinosus (ST) and gracilis (GR) muscles is a common choice for orthopaedic surgeons. However, harvest of the ST and GR tendons leads to post-operative donor muscle atrophy, as well as proximal retraction of the musculotendinous junction. This could in turn, have implications for tibiofemoral joint function, stability and loading. Thus, the overarching purpose of this thesis was to explore the morphological changes that occur to the donor muscles following tendon harvest and their biomechanical consequences.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Allied Health
Griffith Health
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48

Hicks, Kirsty-Marie. "The influence of sex, patella tendon properties and the oral contraceptive pill on markers of exercise-induced muscle damage". Thesis, Manchester Metropolitan University, 2014. http://e-space.mmu.ac.uk/347082/.

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Introduction: Exercise-induced muscle damage (EIMD) is an accepted consequence of eccentric exercise. Sex differences in EIMD are attributed to tendon properties, fascicle lengthening and direct hormonal influences, however these remain unreported in vivo. Furthermore, the classical definition of eccentric contractions omits the role of the elastic tendon in determining eccentric fascicle lengthening and subsequent EIMD. Aim: The overall aims of the current thesis were, to investigate the role of the patella tendon during eccentric contractions, to investigate whether muscle and tendon properties are determinants of EIMD and investigate group differences (sex and oral contraceptive (OCP)use) in EIMD. Materials and method: In brief, vastus lateralis (VL) and patella tendon properties were measured in males, females and female OCP users, using a combination of ultrasonography, electromyography and dynamometry. During maximal voluntary eccentric knee extensions ((MVEKE) 12 reps × 6 sets), VL fascicle lengthening and MVEKE torque was recorded every 10 of knee joint angle (20 - 90). Maximal isometric voluntary knee extensor (MVCKE) torque loss, creatine kinase (CK) and muscle soreness were measured pre, post, 48, 96 and 168 hours post damage as markers of EIMD. Main findings: Patella tendon properties appear to act as a mechanical buffer on VL fascicle lengthening during MVEKE in vivo. Furthermore, due to significantly higher patella tendon stiffness, VL fascicle lengthening was significantly greater in males compared to females. Despite evidencing an attenuating role of the patella tendon on VL fascicle lengthening, patella tendon properties did not correlate with any indirect markers of EIMD, nor did they explain group differences in EIMD. Furthermore, MVEKE torque, MVEKE torque made relative to estimated total quadriceps anatomical cross-sectional area and VL fascicle lengthening did not correlate with any functional indirect marker of EIMD, nor did they explain group differences in EIMD. Within the current thesis CK was the only indirect marker of EIMD to be significantly different between the groups (males > females < OCP users). Creatine kinase was consistently lower in the groups with lower circulating oestrogen levels. Therefore, it was concluded that the antioxidant and membrane stabilising role of oestrogen might explain the group differences in CK reported in the current thesis. Conclusion: In agreement with the historical definition, VL fascicles lengthen during MVEKE. Furthermore, it is evident from the current thesis that patella tendon properties determine the magnitude of VL fascicle lengthening during MVEKE, but do not appear to explain the variability or group differences in EIMD.

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49

Campbell, Emma-Louise. "The role of exercise and amino acid supplementation in disuse-induced muscle and tendon atrophy and subsequent active recovery". Thesis, Manchester Metropolitan University, 2017. http://e-space.mmu.ac.uk/618829/.

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Skeletal muscle atrophy due to disuse is a widespread problem arising from many situations including clinical immobilisation due to injury or disease. As individuals age, the universally observed loss of muscle mass and function known as sarcopenia compounds this problem leading to a significant reduction in locomotor ability and quality of life for sufferers. Recently there has been much work investigating ways to mitigate muscle mass loss in immobilised limbs and to aid in recovery in the post immobilisation phase. Much focus has been placed on recovery protocols based upon either resistance training, nutritional supplementation, or both. In study 1 we report an extensive data set describing in detail skeletal muscle adaptations in structure and function in response to both disuse (ULLS) and retraining. The results indicate that, 1) the loss of muscle force with 3-week unloading in humans is mostly explained by muscle atrophy and a decrease in myosin content and, 2) all the neuromuscular changes induced by this model of disuse can be fully restored after a resistance training intervention of equal duration Study 2 tests the hypothesis that increasing amino acid leucine availability by nutritional supplementation will increase muscle protein synthesis in immobilised muscle and result in mitigating the loss of lean muscle mass. In fact, we found that leucine supplementation alone was not sufficient to maintain muscle mass during 3 weeks of unilateral lower limb suspension. Study 3 examined the effect of leucine supplementation on muscle mass gains during an active recovery training program of muscles previously subjected to ULLS. Despite low participant numbers, the data suggest that leucine supplementation had no effect on the extent to which muscle recovered post ULLS. Study 4 investigates the role of training and immobilization in sarcopenia and discusses the potential of using ultrasound imaging to develop an image based biomarker of sarcopenia. Cross sectional data from both young and old individuals subjected to different loading conditions are analysed in this study. Life-long training appears to slow down the process of sarcopenia whilst periods of disuse due to injury or disease worsen the condition. The change in muscle fibre geometry exhibited in sarcopenia and disuse atrophy could potentially act as a convenient and inexpensive indicator of the onset of sarcopenia.

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Agres, Alison Nicole [Verfasser], Georg N. [Akademischer Betreuer] Duda, Adamantios [Akademischer Betreuer] Arampatzis, William R. [Akademischer Betreuer] Taylor, Marc [Gutachter] Kraft y Georg N. [Gutachter] Duda. "Adaptations in the muscle-tendon unit with rehabilitative training following unilateral Achilles tendon injury / Alison Nicole Agres ; Gutachter: Marc Kraft, Georg N. Duda ; Georg N. Duda, Adamantios Arampatzis, William R. Taylor". Berlin : Technische Universität Berlin, 2016. http://d-nb.info/1156184924/34.

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