Journal articles on the topic 'Muscle-tendon behaviour'

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1

Bonacci, Jason, Wayne Spratford, Claire Kenneally-Dabrowski, Danielle Trowell, and Adrian Lai. "The effect of footwear on mechanical behaviour of the human ankle plantar-flexors in forefoot runners." PLOS ONE 17, no. 9 (September 19, 2022): e0274806. http://dx.doi.org/10.1371/journal.pone.0274806.

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Purpose To compare the ankle plantar-flexor muscle-tendon mechanical behaviour during barefoot and shod forefoot running. Methods Thirteen highly trained forefoot runners performed five overground steady-state running trials (4.5 ± 0.5 m.s-1) while barefoot and shod. Three-dimensional kinematic and ground reaction force data were collected and used as inputs for musculoskeletal modelling. Muscle-tendon behaviour of the ankle plantar-flexors (soleus; medial gastrocnemius; and lateral gastrocnemius) were estimated across the stance phase and compared between barefoot and shod running using a two-way multivariate analysis of variance. Results During barefoot running peak muscle-tendon unit (MTU) power generation was 16.5% (p = 0.01) higher compared to shod running. Total positive MTU work was 18.5% (p = 0.002) higher during barefoot running compared to shod running. The total sum of tendon elastic strain energy was 8% (p = 0.036) greater during barefoot compared to shod running, however the relative contribution of tendon and muscle fibres to muscle-tendon unit positive work was not different between conditions. Conclusion Barefoot forefoot running demands greater muscle and tendon work than shod forefoot running, but the relative contribution of tendon strain energy to overall muscle-tendon unit work was not greater.
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Fukunaga, Tetsuo, Keitaro Kubo, Yasuo Kawakami, Senshi Fukashiro, Hiroaki Kanehisa, and Constantinos N. Maganaris. "In vivo behaviour of human muscle tendon during walking." Proceedings of the Royal Society of London. Series B: Biological Sciences 268, no. 1464 (February 7, 2001): 229–33. http://dx.doi.org/10.1098/rspb.2000.1361.

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3

Alexander, R. McN. "Tendon elasticity and positional control." Behavioral and Brain Sciences 18, no. 4 (December 1995): 745. http://dx.doi.org/10.1017/s0140525x00040711.

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AbstractThe spring-like behaviour of a joint following a sudden change of torque is partly a result of the elastic properties of tendons. A large fall in a muscle with a long tendon may be accompanied by tendon recoil causing joint movements as large as 20°.
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Smart, Rowan R., Cydney M. Richardson, Daryl J. Wile, Brian H. Dalton, and Jennifer M. Jakobi. "Importance of Maximal Strength and Muscle-Tendon Mechanics for Improving Force Steadiness in Persons with Parkinson’s Disease." Brain Sciences 10, no. 8 (July 22, 2020): 471. http://dx.doi.org/10.3390/brainsci10080471.

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Although plantar flexion force steadiness (FS) is reduced in persons with Parkinson’s disease (PD), the underlying causes are unknown. The aim of this exploratory design study was to ascertain the influence of maximal voluntary contraction (MVC) force and gastrocnemius-Achilles muscle-tendon unit behaviour on FS in persons with PD. Nine persons with PD and nine age- and sex-matched non-PD controls (~70 years, 6 females per group) performed plantar flexion MVCs and sub-maximal tracking tasks at 5, 10, 25, 50 and 75% MVC. Achilles tendon elongation and medial gastrocnemius fascicle lengths were recorded via ultrasound during contraction. FS was quantified using the coefficient of variation (CV) of force. Contributions of MVC and tendon mechanics to FS were determined using multiple regression analyses. Persons with PD were 35% weaker during MVC (p = 0.04) and had 97% greater CV (p = 0.01) with 47% less fascicle shortening (p = 0.004) and 38% less tendon elongation (p = 0.002) than controls. Reduced strength was a direct contributor to lower FS in PD (ß = 0.631), and an indirect factor through limiting optimal muscle-tendon unit interaction. Interestingly, our findings indicate an uncoupling between fascicle shortening and tendon elongation in persons with PD. To better understand limitations in FS and muscle-tendon unit behavior, it is imperative to identify the origins of MVC decrements in persons with PD.
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Monte, Andrea, Constantinos Maganaris, Vasilios Baltzopoulos, and Paola Zamparo. "The influence of Achilles tendon mechanical behaviour on “apparent” efficiency during running at different speeds." European Journal of Applied Physiology 120, no. 11 (August 25, 2020): 2495–505. http://dx.doi.org/10.1007/s00421-020-04472-9.

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Abstract Purpose We investigated the role of elastic strain energy on the “apparent” efficiency of locomotion (AE), a parameter that is known to increase as a function of running speed (up to 0.5–0.7) well above the values of “pure” muscle efficiency (about 0.25–0.30). Methods In vivo ultrasound measurements of the gastrocnemius medialis (GM) muscle–tendon unit (MTU) were combined with kinematic, kinetic and metabolic measurements to investigate the possible influence of the Achilles tendon mechanical behaviour on the mechanics (total mechanical work, WTOT) and energetics (net energy cost, Cnet) of running at different speeds (10, 13 and 16 km h−1); AE was calculated as WTOT/Cnet. Results GM fascicles shortened during the entire stance phase, the more so the higher the speed, but the majority of the MTU displacement was accommodated by the Achilles tendon. Tendon strain and recoil increased as a function of running speed (P < 0.01 and P < 0.001, respectively). The contribution of elastic energy to the positive work generated by the MTU also increased with speed (from 0.09 to 0.16 J kg−1 m−1). Significant negative correlations (P < 0.01) were observed between tendon work and metabolic energy at each running speed (the higher the tendon work the lower the metabolic demand) and significant positive correlations were observed between tendon work and AE (P < 0.001) at each running speed (the higher the tendon work the higher the efficiency). Conclusion These results support the notion that the dynamic function of tendons is integral in reducing energy expenditure and increasing the “apparent” efficiency of running.
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Werkhausen, Amelie, Neil J. Cronin, Kirsten Albracht, Gøran Paulsen, Askild V. Larsen, Jens Bojsen-Møller, and Olivier R. Seynnes. "Training-induced increase in Achilles tendon stiffness affects tendon strain pattern during running." PeerJ 7 (April 24, 2019): e6764. http://dx.doi.org/10.7717/peerj.6764.

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Background During the stance phase of running, the elasticity of the Achilles tendon enables the utilisation of elastic energy and allows beneficial contractile conditions for the triceps surae muscles. However, the effect of changes in tendon mechanical properties induced by chronic loading is still poorly understood. We tested the hypothesis that a training-induced increase in Achilles tendon stiffness would result in reduced tendon strain during the stance phase of running, which would reduce fascicle strains in the triceps surae muscles, particularly in the mono-articular soleus. Methods Eleven subjects were assigned to a training group performing isometric single-leg plantarflexion contractions three times per week for ten weeks, and another ten subjects formed a control group. Before and after the training period, Achilles tendon stiffness was estimated, and muscle-tendon mechanics were assessed during running at preferred speed using ultrasonography, kinematics and kinetics. Results Achilles tendon stiffness increased by 18% (P < 0.01) in the training group, but the associated reduction in strain seen during isometric contractions was not statistically significant. Tendon elongation during the stance phase of running was similar after training, but tendon recoil was reduced by 30% (P < 0.01), while estimated tendon force remained unchanged. Neither gastrocnemius medialis nor soleus fascicle shortening during stance was affected by training. Discussion These results show that a training-induced increase in Achilles tendon stiffness altered tendon behaviour during running. Despite training-induced changes in tendon mechanical properties and recoil behaviour, the data suggest that fascicle shortening patterns were preserved for the running speed that we examined. The asymmetrical changes in tendon strain patterns supports the notion that simple in-series models do not fully explain the mechanical output of the muscle-tendon unit during a complex task like running.
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Lai, Adrian, Anthony G. Schache, Nicholas A. T. Brown, and Marcus G. Pandy. "Human ankle plantar flexor muscle–tendon mechanics and energetics during maximum acceleration sprinting." Journal of The Royal Society Interface 13, no. 121 (August 2016): 20160391. http://dx.doi.org/10.1098/rsif.2016.0391.

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Tendon elastic strain energy is the dominant contributor to muscle–tendon work during steady-state running. Does this behaviour also occur for sprint accelerations? We used experimental data and computational modelling to quantify muscle fascicle work and tendon elastic strain energy for the human ankle plantar flexors (specifically soleus and medial gastrocnemius) for multiple foot contacts of a maximal sprint as well as for running at a steady-state speed. Positive work done by the soleus and medial gastrocnemius muscle fascicles decreased incrementally throughout the maximal sprint and both muscles performed more work for the first foot contact of the maximal sprint (FC1) compared with steady-state running at 5 m s −1 (SS5). However, the differences in tendon strain energy for both muscles were negligible throughout the maximal sprint and when comparing FC1 to SS5. Consequently, the contribution of muscle fascicle work to stored tendon elastic strain energy was greater for FC1 compared with subsequent foot contacts of the maximal sprint and compared with SS5. We conclude that tendon elastic strain energy in the ankle plantar flexors is just as vital at the start of a maximal sprint as it is at the end, and as it is for running at a constant speed.
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Bohm, Sebastian, Falk Mersmann, Alessandro Santuz, and Adamantios Arampatzis. "Enthalpy efficiency of the soleus muscle contributes to improvements in running economy." Proceedings of the Royal Society B: Biological Sciences 288, no. 1943 (January 27, 2021): 20202784. http://dx.doi.org/10.1098/rspb.2020.2784.

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During human running, the soleus, as the main plantar flexor muscle, generates the majority of the mechanical work through active shortening. The fraction of chemical energy that is converted into muscular work (enthalpy efficiency) depends on the muscle shortening velocity. Here, we investigated the soleus muscle fascicle behaviour during running with respect to the enthalpy efficiency as a mechanism that could contribute to improvements in running economy after exercise-induced increases of plantar flexor strength and Achilles tendon (AT) stiffness. Using a controlled longitudinal study design ( n = 23) featuring a specific 14-week muscle–tendon training, increases in muscle strength (10%) and tendon stiffness (31%) and reduced metabolic cost of running (4%) were found only in the intervention group ( n = 13, p < 0.05). Following training, the soleus fascicles operated at higher enthalpy efficiency during the phase of muscle–tendon unit (MTU) lengthening (15%) and in average over stance (7%, p < 0.05). Thus, improvements in energetic cost following increases in plantar flexor strength and AT stiffness seem attributed to increased enthalpy efficiency of the operating soleus muscle. The results further imply that the soleus energy production in the first part of stance, when the MTU is lengthening, may be crucial for the overall metabolic energy cost of running.
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9

Waugh, Charlie M., Thomas Korff, and Anthony J. Blazevich. "Developmental differences in dynamic muscle–tendon behaviour: implications for movement efficiency." Journal of Experimental Biology 220, no. 7 (January 20, 2017): 1287–94. http://dx.doi.org/10.1242/jeb.127951.

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10

Kanazawa, Hiroshi, Yukio Urabe, and Taizan Shirakawa. "Behaviour of the muscle-tendon unit during static stretching following unloading." International Journal of Therapy and Rehabilitation 17, no. 3 (March 2010): 132–42. http://dx.doi.org/10.12968/ijtr.2010.17.3.46745.

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11

Gollhofer, A., V. Strojnik, W. Rapp, and L. Schweizer. "Behaviour of triceps surae muscle-tendon complex in different jump conditions." European Journal of Applied Physiology and Occupational Physiology 64, no. 4 (1992): 283–91. http://dx.doi.org/10.1007/bf00636213.

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12

Herbert, Robert D., Jillian Clarke, Li Khim Kwah, Joanna Diong, Josh Martin, Elizabeth C. Clarke, Lynne E. Bilston, and Simon C. Gandevia. "In vivopassive mechanical behaviour of muscle fascicles and tendons in human gastrocnemius muscle-tendon units." Journal of Physiology 589, no. 21 (October 28, 2011): 5257–67. http://dx.doi.org/10.1113/jphysiol.2011.212175.

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13

Blazevich, A., N. Cronin, and G. Lichtwark. "Measuring muscle–tendon behaviour with ultrasound: Theory and practice, pitfalls and promises." Journal of Science and Medicine in Sport 14 (December 2011): e29. http://dx.doi.org/10.1016/j.jsams.2011.11.058.

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14

Kyröläinen, H., T. Finni, J. Avela, and P. V. Komi. "Neuromuscular Behaviour of the Triceps Surae Muscle-Tendon Complex during Running and Jumping." International Journal of Sports Medicine 24, no. 3 (April 2003): 153–55. http://dx.doi.org/10.1055/s-2003-39082.

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15

Ettema, G. J. C. "Contractile behaviour in skeletal muscle-tendon unit during small amplitude sine wave perturbations." Journal of Biomechanics 29, no. 9 (September 1996): 1147–55. http://dx.doi.org/10.1016/0021-9290(96)00014-0.

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16

Ishikawa, M., T. Finni, and P. V. Komi. "Behaviour of vastus lateralis muscle-tendon during high intensity SSC exercises in vivo." Acta Physiologica Scandinavica 178, no. 3 (June 20, 2003): 205–13. http://dx.doi.org/10.1046/j.1365-201x.2003.01149.x.

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17

Romero, F., and F. J. Alonso. "A comparison among different Hill-type contraction dynamics formulations for muscle force estimation." Mechanical Sciences 7, no. 1 (January 18, 2016): 19–29. http://dx.doi.org/10.5194/ms-7-19-2016.

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Abstract. Muscle is a type of tissue able to contract and, thus, shorten, producing a pulling force able to generate movement. The analysis of its activity is essential to understand how the force is generated to perform a movement and how that force can be estimated from direct or indirect measurements. Hill-type muscle model is one of the most used models to describe the mechanism of force production. It is composed by different elements that describe the behaviour of the muscle (contractile, series elastic and parallel elastic element) and tendon. In this work we analyze the differences between different formulations found in the literature for these elements. To evaluate the differences, a flexo-extension movement of the arm was performed, using as input to the different models the surface electromyography signal recorded and the muscle-tendon lengths and contraction velocities obtained by means of inverse dynamic analysis. The results show that the force predicted by the different models is similar and the main differences in muscle force prediction were observed at full-flexion. The results are expected to contribute in the selection of the different formulations of Hill-type muscle model to solve a specific problem.
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Imran, A., R. A. Huss, H. Holstein, and J. J. O'Connor. "The variation in the orientations and moment arms of the knee extensor and flexor muscle tendons with increasing muscle force: A mathematical analysis." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 214, no. 3 (March 1, 2000): 277–86. http://dx.doi.org/10.1243/0954411001535778.

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The orientations and moment arms of the knee extensor and flexor muscle tendons are evaluated with increasing values of muscle force during simulated isometric exercises. A four-bar linkage model of the knee in the sagittal plane was used to define the motion of the joint in the unloaded state during 0–120° flexion. The cruciate and collateral ligaments were represented by arrays of elastic fibres, which were recruited sequentially under load or remained buckled when slack. A bi-articular model of the patello-femoral joint was used. Simple straight-line representation was used for the lines of action of the forces transmitted by the model muscle tendons. The effects of tissue deformation with increasing muscle force were considered. During quadriceps contraction resisted by an external flexing load, the maximum change in moment arm of the patellar tendon was found to be 2 per cent at 0° flexion when the quadriceps force was increased tenfold, from 250 to 2500 N. The corresponding maximum change in orientation of the tendon was 3° at 120° flexion. During hamstrings contraction resisted by an external extending load, the maximum change in moment arm of the hamstrings tendon was 8 per cent at 60° flexion when the hamstrings force was increased tenfold, from 100 to 1000 N. During gastrocnemious contraction, the corresponding maximum change for the gastrocnemious tendon was 3 per cent at 0°. The orientations of the flexor muscle tendons in this range of force either remained constant or changed by 1° or less at any flexion angle. The general trend at any flexion angle was that, as the muscle force was increased, the moment arms and the orientations approached nearly constant values, showing asymptotic behaviour. It is concluded that experimental simulations of knee muscle action with low values of the externally applied load, of the order of 50 N, can provide reliable estimates of the relationships between muscle forces and external loads during activity.
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Monte, Andrea, Paolo Tecchio, Francesca Nardello, and Paola Zamparo. "Achilles Tendon Mechanical Behavior and Ankle Joint Function at the Walk-to-Run Transition." Biology 11, no. 6 (June 14, 2022): 912. http://dx.doi.org/10.3390/biology11060912.

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Walking at speeds higher than transition speed is associated with a decrease in the plantar-flexor muscle fibres’ ability to produce force and, potentially, to an impaired behaviour of the muscle–tendon unit (MTU) elastic components. This study aimed to investigate the ankle joint functional indexes and the Achilles tendon mechanical behaviour (changes in AT force and power) to better elucidate the mechanical determinants of the walk-to-run transition. Kinematics, kinetic and ultrasound data of the gastrocnemius medialis (GM) were investigated during overground walking and running at speeds ranging from 5–9 km·h−1. AT and GM MTU force and power were calculated during the propulsive phase; the ankle joint function indexes (damper, strut, spring and motor) were obtained using a combination of kinetic and kinematic data. AT force was larger in running at speeds > 6.5 km/h. The contribution of AT to the total power provided by the GM MTU was significantly larger in running at speeds > 7.5 km/h. The spring and strut indexes of the ankle were significantly larger in running at speeds > 7.5 km/h. These data suggest that the walk-to-run transition could (at least partially) be explained by the need to preserve AT mechanical behaviour and the ankle spring function.
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Duhautois, B., and B. Pucheu. "Surgical treatment of shoulder instability." Veterinary and Comparative Orthopaedics and Traumatology 21, no. 04 (2008): 368–74. http://dx.doi.org/10.3415/vcot-07-06-0058.

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SummaryThis study evaluates 76 cases of shoulder instability in dogs, functional outcome after treatment, and the effectiveness of medial biceps tendon transposition using a metallic staple. Clinical examinations of the shoulder were performed and radiographs were taken. Conservative treatment or surgery (biceps tendon transposition or arthrodesis) was then opted for on the basis of type of instability, associated lesions and dog (age, weight, behaviour). Long-term functional outcome was categorized as ‘excellent’, ‘good’, ‘average’ or ‘poor’. In our series, the most frequently affected breed was the Poodle (13%). Humeral head intermitent displacement was either medial (80%), lateral (19%) or cranial (1%). On clinical examination, 97% of the animals experienced pain. In anaesthetised dogs, shoulder instability was observed in 90% of the population. Muscle atrophy (33%) and associated radiographic lesions (34%) were less frequent. Ninety-five percent of the dogs were treated surgically, either by bicipital tendon transposition (81%) or by shoulder arthrodesis (19%). Results were ‘good’ to ‘excellent’ in 25% of the animals treated conservatively, and in 84.5% and 87.5%, respectively, in those treated by tendon transposition and arthrodesis. Complications did not arise from the use of a metallic staple to anchor the tendon during medial transposition. Tendon transposition or arthrodesis resulted in a good functional outcome in more than 80% of the dogs with shoulder instability. During the medial transposition, the biceps tendon was easily and effectively stabilized using a metallic staple.
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Grgić, Ivan, Mirko Karakašić, Željko Ivandić, and Tanja Jurčević Jurčević Lulić. "The Development of a Gracilis and Quadriceps Tendons Calibration Device for Uniaxial Tensile Tests." Machines 9, no. 12 (December 17, 2021): 364. http://dx.doi.org/10.3390/machines9120364.

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To determine the biomechanical properties of the distal tendon of the gracilis muscle and the upper third of the quadriceps femoris muscle used for reconstruction of the medial patellofemoral ligament (MPFL), it is necessary to develop a calibration device for specimen preparation for uniaxial tensile tests. The need to develop this device also stems from the fact that there is currently no suitable regulatory or accurate protocol by which soft tissues such as tendons should be tested. In recent studies, various methods have been used to prepare test specimens, such as the use of different ratios of gauge lengths, different gripping techniques, etc., with the aim of obtaining measurable and comparable biomechanical tissue properties. Since tendons, as anisotropic materials, have viscoelastic properties, the guideline for manufacturing calibrator devices was the ISO 527-1:1993 standard, used for testing polymers, since they also have viscoelastic behaviour. The functionality of a calibrator device was investigated by preparing gracilis and quadriceps tendon samples. Fused deposition modeling (FDM) technology was used for the manufacturing of parts with complex geometry. The proposed calibrator could operate in two positions, horizontal and vertical. The maximum gauge length to be achieved was 60 mm, with the maximum tendon length of 120 mm. The average preparation time was 3 min per tendon. It was experimentally proven that it is possible to use a calibrator to prepare tendons for tensile tests. This research can help in the further development of soft tissue testing devices and also in the establishment of standards and exact protocols for their testing.
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Prochazka, Arthur. "Proprioception during voluntary movement." Canadian Journal of Physiology and Pharmacology 64, no. 4 (April 1, 1986): 499–504. http://dx.doi.org/10.1139/y86-081.

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In the last decade, a number of laboratories have accumulated data on the firing of single afferent fibres from muscle and skin during movement in awake cats, monkeys and human subjects. While there is general agreement on the firing behaviour of skin afferents and tendon organ (Ib) afferents during movement, there remains a significant divergence of opinion regarding the way in which the response of muscle spindle afferents (Ia and II) to length changes is modified by fusimotor action (e.g., alpha–gamma linkage versus "fusimotor set"). The controversies surrounding the fusimotor system have tended to overshadow the emergence of several important characteristics of propioceptive behaviour, corroborated in separate laboratories, (i) Mean la firing rates during active movements are nearly always higher than at rest. Thus, activation of the fusimotor system is reserved for the control of, or preparation for, movement. In animals, there is now strong evidence that there is usually a tonic component of fusimotor action during rhythmical movements. (ii) During fast, unloaded movements (peak muscle speeds, 0.2 resting lengths/s or more), the firing of both la and II afferents usually increases during lengthening and decreases during shortening. Ib afferents fire during even the most rapid active shortening of their parent muscles, (iii) During powerful shortening contractions performed against significant loads, la firing is often appreciable, suggesting that there is at least some underlying alpha–gamma coactivation. (iv) During fast imposed muscle stretches, la afferents respond with segmented bursts of firing (threshold speed for segmentation, 0.5–1.0 resting length/s). Ib afferents show far less segmentation of discharge under similar circumstances, (v) There are substantial numbers of tendon organ receptors which fire during tasks involving low levels of force.
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Herssens, Nolan, James Cowburn, Kirsten Albracht, Bjoern Braunstein, Dario Cazzola, Steffi Colyer, Alberto E. Minetti, et al. "Movement in low gravity environments (MoLo) programme–The MoLo-L.O.O.P. study protocol." PLOS ONE 17, no. 11 (November 23, 2022): e0278051. http://dx.doi.org/10.1371/journal.pone.0278051.

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Background Exposure to prolonged periods in microgravity is associated with deconditioning of the musculoskeletal system due to chronic changes in mechanical stimulation. Given astronauts will operate on the Lunar surface for extended periods of time, it is critical to quantify both external (e.g., ground reaction forces) and internal (e.g., joint reaction forces) loads of relevant movements performed during Lunar missions. Such knowledge is key to predict musculoskeletal deconditioning and determine appropriate exercise countermeasures associated with extended exposure to hypogravity. Objectives The aim of this paper is to define an experimental protocol and methodology suitable to estimate in high-fidelity hypogravity conditions the lower limb internal joint reaction forces. State-of-the-art movement kinetics, kinematics, muscle activation and muscle-tendon unit behaviour during locomotor and plyometric movements will be collected and used as inputs (Objective 1), with musculoskeletal modelling and an optimisation framework used to estimate lower limb internal joint loading (Objective 2). Methods Twenty-six healthy participants will be recruited for this cross-sectional study. Participants will walk, skip and run, at speeds ranging between 0.56–3.6 m/s, and perform plyometric movement trials at each gravity level (1, 0.7, 0.5, 0.38, 0.27 and 0.16g) in a randomized order. Through the collection of state-of-the-art kinetics, kinematics, muscle activation and muscle-tendon behaviour, a musculoskeletal modelling framework will be used to estimate lower limb joint reaction forces via tracking simulations. Conclusion The results of this study will provide first estimations of internal musculoskeletal loads associated with human movement performed in a range of hypogravity levels. Thus, our unique data will be a key step towards modelling the musculoskeletal deconditioning associated with long term habitation on the Lunar surface, and thereby aiding the design of Lunar exercise countermeasures and mitigation strategies.
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Arellano, Christopher J., Nicolai Konow, Nicholas J. Gidmark, and Thomas J. Roberts. "Evidence of a tunable biological spring: elastic energy storage in aponeuroses varies with transverse strain in vivo." Proceedings of the Royal Society B: Biological Sciences 286, no. 1900 (April 10, 2019): 20182764. http://dx.doi.org/10.1098/rspb.2018.2764.

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Tendinous structures are generally thought of as biological springs that operate with a fixed stiffness, yet recent observations on the mechanical behaviour of aponeuroses (broad, sheet-like tendons) have challenged this general assumption. During in situ contractions, aponeuroses undergo changes in both length and width and changes in aponeuroses width can drive changes in longitudinal stiffness. Here, we explore if changes in aponeuroses width can modulate elastic energy (EE) storage in the longitudinal direction. We tested this idea in vivo by quantifying muscle and aponeuroses mechanical behaviour in the turkey lateral gastrocnemius during landing and jumping, activities that require rapid rates of energy dissipation and generation, respectively. We discovered that when aponeurosis width increased (as opposed to decreased), apparent longitudinal stiffness was 34% higher and the capacity of aponeuroses to store EE when stretched in the longitudinal direction was 15% lower. These data reveal that biaxial loading of aponeuroses allows for variation in tendon stiffness and energy storage for different locomotor behaviours.
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Kalkman, Barbara M., Lynn Bar-On, Francesco Cenni, Constantinos N. Maganaris, Alfie Bass, Gill Holmes, Kaat Desloovere, Gabor J. Barton, and Thomas D. O'Brien. "Muscle and tendon lengthening behaviour of the medial gastrocnemius during ankle joint rotation in children with cerebral palsy." Experimental Physiology 103, no. 10 (September 13, 2018): 1367–76. http://dx.doi.org/10.1113/ep087053.

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Baudry, S., J. Johannsson, and J. Duchateau. "Behaviour of the muscle–tendon unit of the gastrocnemius medialis and tibialis anterior during forward and backward sways." Computer Methods in Biomechanics and Biomedical Engineering 17, sup1 (July 30, 2014): 184–85. http://dx.doi.org/10.1080/10255842.2014.931674.

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Kawakami, Y., T. Muraoka, S. Ito, H. Kanehisa, and T. Fukunaga. "In vivo muscle fibre behaviour during counter‐movement exercise in humans reveals a significant role for tendon elasticity." Journal of Physiology 540, no. 2 (April 2002): 635–46. http://dx.doi.org/10.1113/jphysiol.2001.013459.

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28

Higham, Timothy E., and Andrew A. Biewener. "Fatigue alters in vivo function within and between limb muscles during locomotion." Proceedings of the Royal Society B: Biological Sciences 276, no. 1659 (December 23, 2008): 1193–97. http://dx.doi.org/10.1098/rspb.2008.1734.

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Muscle fatigue, a reduction in force as a consequence of exercise, is an important factor for any animal that moves, and can result from both peripheral and/or central mechanisms. Although much is known about whole-limb force generation and activation patterns in fatigued muscles under sustained isometric contractions, little is known about the in vivo dynamics of limb muscle function in relation to whole-body fatigue. Here we show that limb kinematics and contractile function in the lateral (LG) and medial (MG) gastrocnemius of helmeted guineafowl ( Numida meleagris ) are significantly altered following fatiguing exercise at 2 m s −1 on an inclined treadmill. The two most significant findings were that the variation in muscle force generation, measured directly from the muscles' tendons, increased significantly with fatigue, and fascicle shortening in the proximal MG, but not the distal MG, decreased significantly with fatigue. We suggest that the former is a potential mechanism for decreased stability associated with fatigue. The region-specific alteration of fascicle behaviour within the MG as a result of fatigue suggests a complex response to fatigue that probably depends on muscle–aponeurosis and tendon architecture not previously explored. These findings highlight the importance of studying the integrative in vivo dynamics of muscle function in response to fatigue.
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Dudek, Michal, and Qing-Jun Meng. "Running on time: the role of circadian clocks in the musculoskeletal system." Biochemical Journal 463, no. 1 (September 8, 2014): 1–8. http://dx.doi.org/10.1042/bj20140700.

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The night and day cycle governs the circadian (24 hourly) rhythm of activity and rest in animals and humans. This is reflected in daily changes of the global gene expression pattern and metabolism, but also in the local physiology of various tissues. A central clock in the brain co-ordinates the rhythmic locomotion behaviour, as well as synchronizing various local oscillators, such as those found in the musculoskeletal system. It has become increasingly recognized that the internal molecular clocks in cells allow a tissue to anticipate the rhythmic changes in their local environment and the specific demands of that tissue. Consequently, the majority of the rhythmic clock controlled genes and pathways are tissue specific. The concept of the tissue-specific function of circadian clocks is further supported by the diverse musculoskeletal phenotypes in mice with deletions or mutations of various core clock components, ranging from increased bone mass, dwarfism, arthropathy, reduced muscle strength and tendon calcification. The present review summarizes the current understanding of the circadian clocks in muscle, bone, cartilage and tendon tissues, with particular focus on the evidence of circadian rhythms in tissue physiology, their entrainment mechanisms and disease links, and the tissue-specific clock target genes/pathways. Research in this area holds strong potential to advance our understanding of how circadian rhythms control the health and disease of the musculoskeletal tissues, which has major implications in diseases associated with advancing age. It could also have potential implications in sports performance and sports medicine.
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30

Aeles, Jeroen, Ilse Jonkers, Sofie Debaere, Christophe Delecluse, and Benedicte Vanwanseele. "Muscle–tendon unit length changes differ between young and adult sprinters in the first stance phase of sprint running." Royal Society Open Science 5, no. 6 (June 2018): 180332. http://dx.doi.org/10.1098/rsos.180332.

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The aim of this study was to compare young and adult sprinters on several biomechanical parameters that were previously highlighted as performance-related and to determine the behaviour of several muscle–tendon units (MTU) in the first stance phase following a block start in sprint running. The ground reaction force (GRF) and kinematic data were collected from 16 adult and 21 young well-trained sprinters. No difference between the groups was found in some of the previously highlighted performance-related parameters (ankle joint stiffness, the range of dorsiflexion and plantar flexor moment). Interestingly, the young sprinters showed a greater maximal and mean ratio of horizontal to total GRF, which was mainly attributed to a greater horizontal GRF relative to body mass and resulted in a greater change in horizontal centre of mass (COM) velocity during the stance phase in the young compared with the adult sprinters. Results from the MTU length analyses showed that adult sprinters had more MTU shortening and higher maximal MTU shortening velocities in all plantar flexors and the rectus femoris. Although previously highlighted performance-related parameters could not explain the greater 100 m sprinting times in the adult sprinters, differences were found in the behaviour of the MTU of the plantar flexors and rectus femoris during the first stance phase. The pattern of length changes in these MTUs provides ideal conditions for the use of elastic energy storage and release for power enhancement.
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31

BYRNE, MARIA. "The Mechanical Properties of the Autotomy Tissues of the Holothurian Eupentacta Quinquesemita and the Effects of Certain Physico-Chemical Agents." Journal of Experimental Biology 117, no. 1 (July 1, 1985): 69–86. http://dx.doi.org/10.1242/jeb.117.1.69.

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Evisceration in the holothurian Eupentacta quinquesemita (Selenka) results from a rapid softening of autotomy structures comprised of connective tissue. The mechanical properties of two autotomy tissues, the introvert and the retractor muscle tendon, were tested to investigate their function in the non-evisceration state and their behaviour during autotomy. The results show that these structures do not have a pre-existing mechanical weakness to account for their rapid failure during evisceration. The autotomy response was mimicked in vitro by increasing K+ concentration. The introvert exhibited viscous behaviour and the absence of Ca2+ and Mg2+ decreased introvert viscosity, whereas excess Ca2+, and low and high pH, increased viscosity. These agents may influence the mechanical properties of the autotomy structures by directly affecting connective tissue ionic interactions and may induce proteoglycan conformational changes. K+ may also exert an indirect effect through responses of cells controlling connective tissue tensility. The most likely mechanism of autotomy is through an alteration of connective tissue ionic interactions.
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32

Ettema, G. J. "Elastic and length-force characteristics of the gastrocnemius of the hopping mouse (Notomys alexis) and the rat (Rattus norvegicus)." Journal of Experimental Biology 199, no. 6 (June 1, 1996): 1277–85. http://dx.doi.org/10.1242/jeb.199.6.1277.

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The aim of this study was to compare the contractile and series elastic properties of terrestrial mammals that use bipedal versus quadrupedal gaits. The gastrocnemius muscle of the hopping mouse (body mass 30.2 +/- 2.4 g, mean +/- S.D.) and the rat (313 +/- 10.7 g) were compared with data from the literature for the wallaby and the kangaroo rat to distinguish scaling effects and locomotion-related effects on muscle properties. Contractile length-force properties and series elastic stiffness were measured in situ during maximal tetanic contractions. The rat had a larger muscle-fibre-to-tendon-length ratio. The rat and hopping mouse showed similar normalised length-force characteristics of the gastrocnemius. Normalised stiffness in the hopping mouse was higher. The hopping mouse showed a higher capacity to store elastic energy per unit of contractile work capacity, as well as per unit of body mass. Accounting for body size differences, the rat had a smaller relative muscle mass and thus smaller work capacity than the three hopping animals considered. This is an agreement with a quadrupedal versus bipedal locomotion style. The differences in contractile and elastic properties of the gastrocnemius of the rat and hopping mouse seem to be closely related to locomotion patterns. Small animals seem to be able to utilise the storage and release of elastic energy to a far lesser extent than larger animals. However, even in animals as small as hopping mice, the storage and utilisation of elastic energy during locomotion is of functional significance and probably depends on locomotor behaviour.
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33

Markowitz, Jared, Pavitra Krishnaswamy, Michael F. Eilenberg, Ken Endo, Chris Barnhart, and Hugh Herr. "Speed adaptation in a powered transtibial prosthesis controlled with a neuromuscular model." Philosophical Transactions of the Royal Society B: Biological Sciences 366, no. 1570 (May 27, 2011): 1621–31. http://dx.doi.org/10.1098/rstb.2010.0347.

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Control schemes for powered ankle–foot prostheses would benefit greatly from a means to make them inherently adaptive to different walking speeds. Towards this goal, one may attempt to emulate the intact human ankle, as it is capable of seamless adaptation. Human locomotion is governed by the interplay among legged dynamics, morphology and neural control including spinal reflexes. It has been suggested that reflexes contribute to the changes in ankle joint dynamics that correspond to walking at different speeds. Here, we use a data-driven muscle–tendon model that produces estimates of the activation, force, length and velocity of the major muscles spanning the ankle to derive local feedback loops that may be critical in the control of those muscles during walking. This purely reflexive approach ignores sources of non-reflexive neural drive and does not necessarily reflect the biological control scheme, yet can still closely reproduce the muscle dynamics estimated from biological data. The resulting neuromuscular model was applied to control a powered ankle–foot prosthesis and tested by an amputee walking at three speeds. The controller produced speed-adaptive behaviour; net ankle work increased with walking speed, highlighting the benefits of applying neuromuscular principles in the control of adaptive prosthetic limbs.
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34

Guo, Jianqiao, Yajun Yin, and Gang Peng. "Fractional-order viscoelastic model of musculoskeletal tissues: correlation with fractals." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 477, no. 2249 (May 2021): 20200990. http://dx.doi.org/10.1098/rspa.2020.0990.

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Self-similar fractals are widely obtained from biomaterials within the human musculoskeletal system, and their viscoelastic behaviours can be described by fractional-order derivatives. However, existing viscoelastic models neglect the internal correlation between the fractal structure of biomaterials and their fractional-order temporal responses. We further expanded the fractal hyper-cell (FHC) viscoelasticity theory to investigate this spatio-temporal correlation. The FHC element was first compared with other material elements and spring–dashpot viscoelastic models, thereby highlighting its discrete and fractal nature. To demonstrate the utility of an FHC, tree-like, ladder-like and triangle-like FHCs were abstracted from human cartilage, tendons and muscle cross-sections, respectively. The duality and symmetry of the FHC element were further discussed, where operating the duality transformation generated new types of FHC elements, and the symmetry breaking of an FHC altered its fractional-order viscoelastic responses. Thus, the correlations between the staggering patterns of FHCs and their rheological power-law orders were established, and the viscoelastic behaviour of the multi-level FHC elements fitted well in stress relaxation experiments at both the macro- and nano-levels of the tendon hierarchy. The FHC element provides a theoretical basis for understanding the connections between structural degeneration of bio-tissues during ageing or disease and their functional changes.
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Ettema, G. J., P. A. Huijing, and A. de Haan. "The potentiating effect of prestretch on the contractile performance of rat gastrocnemius medialis muscle during subsequent shortening and isometric contractions." Journal of Experimental Biology 165, no. 1 (April 1, 1992): 121–36. http://dx.doi.org/10.1242/jeb.165.1.121.

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The aim of the present study was to investigate the effect of an active stretch during the onset of a muscle contraction on subsequent active behaviour of the contractile machinery within an intact mammalian muscle-tendon complex. Muscle length and shortening velocity were studied because they may be important variables affecting this so-called prestretch effect. Seven gastrocnemius medialis (GM) muscles of the rat were examined. Tetanic, isovelocity shortening contractions from 3 mm above muscle optimum length (l0) to l0 - 2 mm, at velocities of 10–50 mm s-1 (dynamic experiments), were preceded by either an isometric contraction (PI) or an active stretch (PS). By imposing quick length decreases between the prephase and the concentric phase, all excess force generated in the prephase was instantaneously eliminated. This procedure only allowed small force changes during subsequent shortening (caused by the intrinsic properties of the contractile machinery). In this way, the influence of series elastic structures on subsequent muscle performance was minimized. Experiments were also performed at lengths ranging from l0 + 2.5 mm to l0 - 1.5 mm, keeping the length constant after the initial quick length changes (isometric experiments). For the dynamic experiments, enhancement of the performance of the contractile machinery (potentiation) was calculated as the ratio of the average force level over each millimetre of shortening during PS to that during PI conditions (PS/PI). For the isometric experiments, the PS/PI force ratio after 300 ms of stimulation was used. The main result of the present study confirmed results reported in the literature and experiments on isolated muscle fibres. For all conditions, a potentiation effect was found, ranging from about 2 to 16%. Muscle length appeared to have a large positive effect on the degree of potentiation. At the greatest lengths potentiation was largest, but at lengths below optimum a small effect was also found. A negative influence of shortening velocity was mainly present at increased muscle lengths (l0 + 2.5 mm and l0 + 1.5 mm). For the dynamic experiments, no interaction was found between the effects of muscle length and shortening velocity on potentiation. However, there was a clear difference between the isometric and dynamic responses: the dependence of potentiation on muscle length was significantly greater for the isometric contractions than for the dynamic ones. These isometric-dynamic differences indicate that the processes underlying prestretch effects operate differently under isometric and dynamic conditions.(ABSTRACT TRUNCATED AT 400 WORDS)
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36

Backus, Spencer B., Diego Sustaita, Lael U. Odhner, and Aaron M. Dollar. "Mechanical analysis of avian feet: multiarticular muscles in grasping and perching." Royal Society Open Science 2, no. 2 (February 2015): 140350. http://dx.doi.org/10.1098/rsos.140350.

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The grasping capability of birds' feet is a hallmark of their evolution, but the mechanics of avian foot function are not well understood. Two evolutionary trends that contribute to the mechanical complexity of the avian foot are the variation in the relative lengths of the phalanges and the subdivision and variation of the digital flexor musculature observed among taxa. We modelled the grasping behaviour of a simplified bird foot in response to the downward and upward forces imparted by carrying and perching tasks, respectively. Specifically, we compared the performance of various foot geometries performing these tasks when actuated by distally inserted flexors only, versus by both distally inserted and proximally inserted flexors. Our analysis demonstrates that most species possess relative phalanx lengths that are conducive to grasps actuated only by a single distally inserted tendon per digit. Furthermore, proximally inserted flexors are often required during perching, but the distally inserted flexors are sufficient when grasping and carrying objects. These results are reflected in differences in the relative development of proximally and distally inserted digital flexor musculature among ‘perching’ and ‘grasping’ taxa. Thus, our results shed light on the relative roles of variation in phalanx length and digit flexor muscle distribution in an integrative, mechanical context.
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Srinivasan, Manoj. "Fifteen observations on the structure of energy-minimizing gaits in many simple biped models." Journal of The Royal Society Interface 8, no. 54 (June 11, 2010): 74–98. http://dx.doi.org/10.1098/rsif.2009.0544.

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A popular hypothesis regarding legged locomotion is that humans and other large animals walk and run in a manner that minimizes the metabolic energy expenditure for locomotion. Here, using numerical optimization and supporting analytical arguments, I obtain the energy-minimizing gaits of many different simple biped models. I consider bipeds with point-mass bodies and massless legs, with or without a knee, with or without a springy tendon in series with the leg muscle and minimizing one of many different ‘metabolic cost’ models—correlated with muscle work, muscle force raised to some power, the Minetti–Alexander quasi-steady approximation to empirical muscle metabolic rate (from heat and ATPase activity), a new cost function called the ‘generalized work cost’ C g having some positivity and convexity properties (and includes the Minetti–Alexander cost and the work cost as special cases), and generalizations thereof. For many of these models, walking-like gaits are optimal at low speeds and running-like gaits at higher speeds, so a gait transition is optimal. Minimizing the generalized work cost C g appears mostly indistinguishable from minimizing muscle work for all the models. Inverted pendulum walking and impulsive running gaits minimize the work cost, generalized work costs C g and a few other costs for the springless bipeds; in particular, a knee-torque-squared cost, appropriate as a simplified model for electric motor power for a kneed robot biped. Many optimal gaits had symmetry properties; for instance, the left stance phase was identical to the right stance phases. Muscle force–velocity relations and legs with masses have predictable qualitative effects, if any, on the optima. For bipeds with compliant tendons, the muscle work-minimizing strategies have close to zero muscle work (isometric muscles), with the springs performing all the leg work. These zero work gaits also minimize the generalized work costs C g with substantial additive force or force rate costs, indicating that a running animal's metabolic cost could be dominated by the cost of producing isometric force, even though performing muscle work is usually expensive. I also catalogue the many differences between the optimal gaits of the various models. These differences contain information that might help us develop models that better predict locomotion data. In particular, for some biologically plausible cost functions, the presence or absence of springs in series with muscles has a large effect on both the coordination strategy and the absolute cost; the absence of springs results in more impulsive (collisional) optimal gaits and the presence of springs leads to more compliant optimal gaits. Most results are obtained for specific speed and stride length combinations close to preferred human behaviour, but limited numerical experiments show that some qualitative results extend to other speed-stride length combinations as well.
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38

Hauraix, Hugo, Antoine Nordez, and Sylvain Dorel. "Shortening behavior of the different components of muscle-tendon unit during isokinetic plantar flexions." Journal of Applied Physiology 115, no. 7 (October 1, 2013): 1015–24. http://dx.doi.org/10.1152/japplphysiol.00247.2013.

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The torque-velocity relationship has been widely considered as reflecting the mechanical properties of the contractile apparatus, and the influence of tendinous tissues on this relationship obtained during in vivo experiments remains to be determined. This study describes the pattern of shortening of various muscle-tendon unit elements of the triceps surae at different constant angular velocities and quantifies the contributions of fascicles, tendon, and aponeurosis to the global muscle-tendon unit shortening. Ten subjects performed isokinetic plantar flexions at different preset angular velocities (i.e., 30, 90, 150, 210, 270, and 330°/s). Ultrafast ultrasound measurements were performed on the muscle belly and on the myotendinous junction of the medial and lateral gastrocnemius muscles. The contributions of fascicles, tendon, and aponeurosis to global muscle-tendon unit shortening velocity were calculated for velocity conditions for four parts of the total range of motion. For both muscles, the fascicles' contribution decreased throughout the motion (73.5 ± 21.5% for 100–90° angular range to 33.7 ± 20.2% for 80–70°), whereas the tendon contribution increased (25.8 ± 15.4 to 55.6 ± 16.8%). In conclusion, the tendon contribution to the global muscle-tendon unit shortening is significant even during a concentric contraction. However, this contribution depends on the range of motion analyzed. The intersubject variability found in the maximal fascicle shortening velocity, for a given angular velocity, suggests that some subjects might possess a more efficient musculoarticular complex to produce the movement velocity. These findings are of great interest for understanding the ability of muscle-tendon shortening velocity.
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Lai, Adrian, Glen A. Lichtwark, Anthony G. Schache, Yi-Chung Lin, Nicholas A. T. Brown, and Marcus G. Pandy. "In vivo behavior of the human soleus muscle with increasing walking and running speeds." Journal of Applied Physiology 118, no. 10 (May 15, 2015): 1266–75. http://dx.doi.org/10.1152/japplphysiol.00128.2015.

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The interaction between the muscle fascicle and tendon components of the human soleus (SO) muscle influences the capacity of the muscle to generate force and mechanical work during walking and running. In the present study, ultrasound-based measurements of in vivo SO muscle fascicle behavior were combined with an inverse dynamics analysis to investigate the interaction between the muscle fascicle and tendon components over a broad range of steady-state walking and running speeds: slow-paced walking (0.7 m/s) through to moderate-paced running (5.0 m/s). Irrespective of a change in locomotion mode (i.e., walking vs. running) or an increase in steady-state speed, SO muscle fascicles were found to exhibit minimal shortening compared with the muscle-tendon unit (MTU) throughout stance. During walking and running, the muscle fascicles contributed only 35 and 20% of the overall MTU length change and shortening velocity, respectively. Greater levels of muscle activity resulted in increasingly shorter SO muscle fascicles as locomotion speed increased, both of which facilitated greater tendon stretch and recoil. Thus the elastic tendon contributed the majority of the MTU length change during walking and running. When transitioning from walking to running near the preferred transition speed (2.0 m/s), greater, more economical ankle torque development is likely explained by the SO muscle fascicles shortening more slowly and operating on a more favorable portion (i.e., closer to the plateau) of the force-length curve.
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Tsui, Chi Pong, Chak Yin Tang, Chi Loong Chow, S. C. Hui, and Y. L. Hong. "Active Finite Element Method for Simulating the Contraction Behavior of a Muscle-Tendon Complex." Advanced Materials Research 9 (September 2005): 9–14. http://dx.doi.org/10.4028/www.scientific.net/amr.9.9.

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A three-dimensional finite element analysis was conducted to simulate the effects of the varying material parameters on the contraction behaviors of a muscle-tendon complex using an active finite element method. The material behavior of the skeletal muscle was assumed to be orthotropic and the muscle model consists of two parts: the active and the passive parts. An active finite element method was then used for accommodating both the active and passive behaviors of the muscle into the muscle model. In this active-passive muscle model, the active component is governed by an activation level, a time period, a muscle sensitivity parameter and a strain rate. The material property of the passive component was assumed to be viscoelastic and the tendon is assumed to be linear elastic. The effects of activation amplitude and viscoelastic material parameters on the active, passive and total force-length relationship of the cat muscle under isometric contraction were predicted. The predicted results were found to be close to the experimental data reported in the available literature. Hence, the active-passive muscle model was extended to simulate the stress distribution of the cat muscle subject to shortening contraction and different activation amplitude. By varying the magnitude of the material parameters, different muscle behaviors could be generated. The proposed active finite element method lays a good foundation for simulation of human musculoskeletal motion.
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41

Fukashiro, Senshi, Dean C. Hay, and Akinori Nagano. "Biomechanical Behavior of Muscle-Tendon Complex during Dynamic Human Movements." Journal of Applied Biomechanics 22, no. 2 (May 2006): 131–47. http://dx.doi.org/10.1123/jab.22.2.131.

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This paper reviews the research findings regarding the force and length changes of the muscle-tendon complex during dynamic human movements, especially those using ultrasonography and computer simulation. The use of ultrasonography demonstrated that the tendinous structures of the muscle-tendon complex are compliant enough to influence the biomechanical behavior (length change, shortening velocity, and so on) of fascicles substantially. It was discussed that the fascicles are a force generator rather than a work generator; the tendinous structures function not only as an energy re-distributor but also as a power amplifier, and the interaction between fascicles and tendinous structures is essential for generating higher joint power outputs during the late pushoff phase in human vertical jumping. This phenomenon could be explained based on the force-length/velocity relationships of each element (contractile and series elastic elements) in the muscle-tendon complex during movements. Through computer simulation using a Hill-type muscle-tendon complex model, the benefit of making a countermovement was examined in relation to the compliance of the muscle-tendon complex and the length ratio between the contractile and series elastic elements. Also, the integral roles of the series elastic element were simulated in a cyclic human heel-raise exercise. It was suggested that the storage and reutilization of elastic energy by the tendinous structures play an important role in enhancing work output and movement efficiency in many sorts of human movements.
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42

Tellechea, Javier S., Franco Teixeira-de Mello, Iván Gonzalez-Bergonzoni, and Nicolás Vidal. "Sound production and pectoral spine locking in a Neotropical catfish (Iheringichthys labrosus, Pimelodidae)." Neotropical Ichthyology 9, no. 4 (November 1, 2011): 889–94. http://dx.doi.org/10.1590/s1679-62252011005000041.

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Catfishes may have two sonic organs: pectoral spines for stridulation and swimbladder drumming muscles. The aim of this study was to characterize the sound production of the catfish Iheringichthys labrosus. The I. labrosus male and female emits two different types of sounds: stridulatory sounds (655.8 + 230 Hz) consisting of a train of pulses, and drumming sounds (220 + 46 Hz), which are composed of single-pulse harmonic signals. Stridulatory sounds are emitted during abduction of the pectoral spine. At the base of the spine there is a dorsal process that bears a series of ridges on its latero-ventral surface, and by pressing the ridges against the groove (with an unspecialized rough surface) during a fin sweep, the animal produce a series of short pulses. Drumming sound is produced by an extrinsic sonic muscle, originated on a flat tendon of the transverse process of the fourth vertebra and inserted on the rostral and ventral surface of the swimbladder. The sounds emitted by both mechanisms are emitted in distress situation. Distress was induced by manipulating fish in a laboratory tank while sounds were recorded. Our results indicate that the catfish initially emits a stridulatory sound, which is followed by a drumming sound. Simultaneous production of stridulatory and drumming sounds was also observed. The catfish drumming sounds were lower in dominant frequency than stridulatory sounds, and also exhibited a small degree of dominant frequency modulation. Another behaviour observed in this catfish was the pectoral spine locking. This reaction was always observed before the distress sound production. Like other authors outline, our results suggest that in the catfish I. labrosus stridulatory and drumming sounds may function primarily as a distress call.
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43

Robertson, Benjamin D., and Gregory S. Sawicki. "Unconstrained muscle-tendon workloops indicate resonance tuning as a mechanism for elastic limb behavior during terrestrial locomotion." Proceedings of the National Academy of Sciences 112, no. 43 (October 12, 2015): E5891—E5898. http://dx.doi.org/10.1073/pnas.1500702112.

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In terrestrial locomotion, there is a missing link between observed spring-like limb mechanics and the physiological systems driving their emergence. Previous modeling and experimental studies of bouncing gait (e.g., walking, running, hopping) identified muscle-tendon interactions that cycle large amounts of energy in series tendon as a source of elastic limb behavior. The neural, biomechanical, and environmental origins of these tuned mechanics, however, have remained elusive. To examine the dynamic interplay between these factors, we developed an experimental platform comprised of a feedback-controlled servo-motor coupled to a biological muscle-tendon. Our novel motor controller mimicked in vivo inertial/gravitational loading experienced by muscles during terrestrial locomotion, and rhythmic patterns of muscle activation were applied via stimulation of intact nerve. This approach was based on classical workloop studies, but avoided predetermined patterns of muscle strain and activation—constraints not imposed during real-world locomotion. Our unconstrained approach to position control allowed observation of emergent muscle-tendon mechanics resulting from dynamic interaction of neural control, active muscle, and system material/inertial properties. This study demonstrated that, despite the complex nonlinear nature of musculotendon systems, cyclic muscle contractions at the passive natural frequency of the underlying biomechanical system yielded maximal forces and fractions of mechanical work recovered from previously stored elastic energy in series-compliant tissues. By matching movement frequency to the natural frequency of the passive biomechanical system (i.e., resonance tuning), muscle-tendon interactions resulting in spring-like behavior emerged naturally, without closed-loop neural control. This conceptual framework may explain the basis for elastic limb behavior during terrestrial locomotion.
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44

Maceri, Franco, Michele Marino, and Giuseppe Vairo. "An insight on multiscale tendon modeling in muscle–tendon integrated behavior." Biomechanics and Modeling in Mechanobiology 11, no. 3-4 (July 8, 2011): 505–17. http://dx.doi.org/10.1007/s10237-011-0329-8.

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Dick, Taylor J. M., Laksh K. Punith, and Gregory S. Sawicki. "Humans falling in holes: adaptations in lower-limb joint mechanics in response to a rapid change in substrate height during human hopping." Journal of The Royal Society Interface 16, no. 159 (October 2, 2019): 20190292. http://dx.doi.org/10.1098/rsif.2019.0292.

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In getting from here to there, we continuously negotiate complex environments and unpredictable terrain. Our ability to stay upright in the face of obstacles, such as holes in the ground, is quite remarkable. However, we understand relatively little about how humans adjust limb mechanical behaviour to recover from unexpected perturbations. In this study, we determined how the joints of the lower-limb respond to recover from a rapid, unexpected drop in substrate height during human hopping. We recorded lower-limb kinematics and kinetics while subjects performed steady-state hopping at their preferred frequency on an elevated platform (5, 10 and 20 cm). At an unknown time, we elicited an unexpected perturbation (i.e. a hole in the ground) via the rapid removal of the platform. Based on previous research in bipedal birds, we hypothesized (i) that distal joints would play an increased role in fall recovery when compared to steady-state hopping, and (ii) that patterns of joint power redistribution would be more pronounced with increases in perturbation height. Our results suggest that humans successfully recover from falling in a hole by increasing the energy absorbed predominantly in distal lower-limb joints (i.e. the ankle) across perturbation heights ranging from 5 to 10 cm. However, with increased perturbation height (20 cm) humans increase their reliance on the more proximal lower-limb joints (i.e. the knee and the hip) to absorb mechanical energy and stabilize fall recovery. Further investigations into the muscle–tendon mechanics underlying these joint-level responses will likely provide additional insights into the neuromotor control strategies used to regain the stability following unexpected perturbations and provide biological inspiration for the future design of wearable devices capable of performing within unpredictable environments.
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46

Fouré, Alexandre, Antoine Nordez, and Christophe Cornu. "Effects of eccentric training on mechanical properties of the plantar flexor muscle-tendon complex." Journal of Applied Physiology 114, no. 5 (March 1, 2013): 523–37. http://dx.doi.org/10.1152/japplphysiol.01313.2011.

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Eccentric training is a mechanical loading classically used in clinical environment to rehabilitate patients with tendinopathies. In this context, eccentric training is supposed to alter tendon mechanical properties but interaction with the other components of the muscle-tendon complex remains unclear. The aim of this study was to determine the specific effects of 14 wk of eccentric training on muscle and tendon mechanical properties assessed in active and passive conditions in vivo. Twenty-four subjects were randomly divided into a trained group ( n = 11) and a control group ( n = 13). Stiffness of the active and passive parts of the series elastic component of plantar flexors were determined using a fast stretch during submaximal isometric contraction, Achilles tendon stiffness and dissipative properties were assessed during isometric plantar flexion, and passive stiffness of gastrocnemii muscles and Achilles tendon were determined using ultrasonography while ankle joint was passively moved. A significant decrease in the active part of the series elastic component stiffness was found ( P < 0.05). In contrast, a significant increase in Achilles tendon stiffness determined under passive conditions was observed ( P < 0.05). No significant change in triceps surae muscles and Achilles tendon geometrical parameters was shown ( P > 0.05). Specific changes in muscle and tendon involved in plantar flexion are mainly due to changes in intrinsic mechanical properties of muscle and tendon tissues. Specific assessment of both Achilles tendon and plantar flexor muscles allowed a better understanding of the functional behavior of the muscle-tendon complex and its adaptation to eccentric training.
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47

Vila Pouca, Maria C. P., Marco P. L. Parente, Renato M. Natal Jorge, and James A. Ashton-Miller. "Injuries in Muscle-Tendon-Bone Units: A Systematic Review Considering the Role of Passive Tissue Fatigue." Orthopaedic Journal of Sports Medicine 9, no. 8 (August 1, 2021): 232596712110207. http://dx.doi.org/10.1177/23259671211020731.

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Background: Low-cycle fatigue damage accumulating to the point of structural failure has been recently reported at the origin of the human anterior cruciate ligament under strenuous repetitive loading. If this can occur in a ligament, low-cycle fatigue damage may also occur in the connective tissue of muscle-tendon units. To this end, we reviewed what is known about how, when, and where injuries of muscle-tendon units occur throughout the body. Purpose: To systematically review injuries in the muscle-tendon-bone complex; assess the site of injury (muscle belly, musculotendinous junction [MTJ], tendon/aponeurosis, tendon/aponeurosis–bone junction, and tendon/aponeurosis avulsion), incidence, muscles and tendons involved, mechanism of injury, and main symptoms; and consider the hypothesis that injury may often be consistent with the accumulation of multiscale material fatigue damage during repetitive submaximal loading regimens. Methods: PubMed, Web of Science, Scopus, and ProQuest were searched on July 24, 2019. Quality assessment was undertaken using ARRIVE, STROBE, and CARE (Animal Research: Reporting In Vivo Experiments, Strengthening the Reporting of Observational Studies in Epidemiology, and the Case Report Statement and Checklist, respectively). Results: Overall, 131 studies met the inclusion criteria, including 799 specimens and 2,823 patients who sustained 3,246 injuries. Laboratory studies showed a preponderance of failures at the MTJ, a viscoelastic behavior of muscle-tendon units, and damage accumulation at the MTJ with repetitive loading. Observational studies showed that 35% of injuries occurred in the tendon midsubstance; 28%, at the MTJ; 18%, at the tendon-bone junction; 13%, within the muscle belly and that 6% were tendon avulsions including a bone fragment. The biceps femoris was the most injured muscle (25%), followed by the supraspinatus (12%) and the Achilles tendon (9%). The most common symptoms were hematoma and/or swelling, tenderness, edema and muscle/tendon retraction. The onset of injury was consistent with tissue fatigue at all injury sites except for tendon avulsions, where 63% of the injuries were caused by an evident trauma. Conclusion: Excluding traumatic tendon avulsions, most injuries were consistent with the hypothesis that material fatigue damage accumulated during repetitive submaximal loading regimens. If supported by data from better imaging modalities, this has implications for improving injury detection, prevention, and training regimens.
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48

LaCroix, Andrew S., Sarah E. Duenwald-Kuehl, Roderic S. Lakes, and Ray Vanderby. "Relationship between tendon stiffness and failure: a metaanalysis." Journal of Applied Physiology 115, no. 1 (July 1, 2013): 43–51. http://dx.doi.org/10.1152/japplphysiol.01449.2012.

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Tendon is a highly specialized, hierarchical tissue designed to transfer forces from muscle to bone; complex viscoelastic and anisotropic behaviors have been extensively characterized for specific subsets of tendons. Reported mechanical data consistently show a pseudoelastic, stress-vs.-strain behavior with a linear slope after an initial toe region. Many studies report a linear, elastic modulus, or Young's modulus (hereafter called elastic modulus) and ultimate stress for their tendon specimens. Individually, these studies are unable to provide a broader, interstudy understanding of tendon mechanical behavior. Herein we present a metaanalysis of pooled mechanical data from a representative sample of tendons from different species. These data include healthy tendons and those altered by injury and healing, genetic modification, allograft preparation, mechanical environment, and age. Fifty studies were selected and analyzed. Despite a wide range of mechanical properties between and within species, elastic modulus and ultimate stress are highly correlated ( R2 = 0.785), suggesting that tendon failure is highly strain-dependent. Furthermore, this relationship was observed to be predictable over controlled ranges of elastic moduli, as would be typical of any individual species. With the knowledge gained through this metaanalysis, noninvasive tools could measure elastic modulus in vivo and reasonably predict ultimate stress (or structural compromise) for diseased or injured tendon.
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49

Lanferdini, Fábio J., Rodrigo R. Bini, Pedro Figueiredo, Fernando Diefenthaeler, Carlos B. Mota, Anton Arndt, and Marco A. Vaz. "Differences in Pedaling Technique in Cycling: A Cluster Analysis." International Journal of Sports Physiology and Performance 11, no. 7 (October 2016): 959–64. http://dx.doi.org/10.1123/ijspp.2015-0142.

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Purpose:To employ cluster analysis to assess if cyclists would opt for different strategies in terms of neuromuscular patterns when pedaling at the power output of their second ventilatory threshold (POVT2) compared with cycling at their maximal power output (POMAX).Methods:Twenty athletes performed an incremental cycling test to determine their power output (POMAX and POVT2; first session), and pedal forces, muscle activation, muscle–tendon unit length, and vastus lateralis architecture (fascicle length, pennation angle, and muscle thickness) were recorded (second session) in POMAX and POVT2. Athletes were assigned to 2 clusters based on the behavior of outcome variables at POVT2 and POMAX using cluster analysis.Results:Clusters 1 (n = 14) and 2 (n = 6) showed similar power output and oxygen uptake. Cluster 1 presented larger increases in pedal force and knee power than cluster 2, without differences for the index of effectiveness. Cluster 1 presented less variation in knee angle, muscle–tendon unit length, pennation angle, and tendon length than cluster 2. However, clusters 1 and 2 showed similar muscle thickness, fascicle length, and muscle activation. When cycling at POVT2 vs POMAX, cyclists could opt for keeping a constant knee power and pedal-force production, associated with an increase in tendon excursion and a constant fascicle length.Conclusions:Increases in power output lead to greater variations in knee angle, muscle–tendon unit length, tendon length, and pennation angle of vastus lateralis for a similar knee-extensor activation and smaller pedal-force changes in cyclists from cluster 2 than in cluster 1.
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50

Ito, Masamitsu, Yasuo Kawakami, Yoshiho Ichinose, Senshi Fukashiro, and Tetsuo Fukunaga. "Nonisometric behavior of fascicles during isometric contractions of a human muscle." Journal of Applied Physiology 85, no. 4 (October 1, 1998): 1230–35. http://dx.doi.org/10.1152/jappl.1998.85.4.1230.

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Fascicle length, pennation angle, and tendon elongation of the human tibialis anterior were measured in vivo by ultrasonography. Subjects ( n = 9) were requested to develop isometric dorsiflexion torque gradually up to maximal at the ankle joint angle of 20° plantarflexion from the anatomic position. Fascicle length shortened from 90 ± 7 to 76 ± 7 (SE) mm, pennation angle increased from 10 ± 1 to 12 ± 1°, and tendon elongation increased up to 15 ± 2 mm with graded force development up to maximum. The tendon stiffness increased with increasing tendon force from 10 N/mm at 0–20 N to 32 N/mm at 240–260 N. Young’s modulus increased from 157 MPa at 0–20 N to 530 MPa at 240–260 N. It can be concluded that, in isometric contractions of a human muscle, mechanical work, some of which is absorbed by the tendinous tissue, is generated by the shortening of muscle fibers and that ultrasonography can be used to determine the stiffness and Young’s modulus for human tendons.
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