Dissertations / Theses on the topic 'Eccentric exercise'
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Marginson, Vicky. "Symptoms of exercise-induced muscle damage in boys and men following eccentric exercise." Thesis, Bangor University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252400.
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Yarrow, Joshua F. "Neuroendocrine and performance responses to eccentric-enhanced resistance exercise." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0016120.
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Howatson, Glyn. "Eccentric exercise and muscle damage : treatment, prevention and cross-education." Thesis, Kingston University, 2005. http://eprints.kingston.ac.uk/20368/.
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Eccentric biased muscular contractions, when compared to concentric and isometric muscle actions have a number of benefits, which include greater hypertrophy, increased strength and a reduced metabolic cost at any given intensity. The literature has reported the benefits of eccentric contractions in a variety of populations, which include exercisers, athletes, geriatric and chronically diseased communities. However, eccentric contractions can result in temporary exercise-induced muscle damage (EIMD) that reduces function and causes soreness. Consequently, a number of interventions, such as post-exercise therapies and prior exercise have been used in an attempt to attenuate the negative effects of this muscle action. Therefore, the purpose of this thesis is to provide novel data to expand the existing body of knowledge and investigate a cryotherapeutic intervention that may attenuate the symptoms of exercise-induced muscle damage. Furthermore, this work examines the adaptation to prior exercise (the repeated bout effect) in the ipsilateral and contralateral limbs to provide additional novel data to elucidate the possible mechanisms responsible for adaptation. Study 1: The aims of the first study were to investigate the effects of repeated applications of ice massage on the markers of muscle damage using a within-subject, cross-over design and to examine the effects on muscle function during static and dynamic contractions. The results suggest that ice massage does not reduce any of the signs or symptoms of EIMD after high intensity eccentric exercise, nor does it return the function of static or dynamic muscle actions following a damaging bout of exercise. Study 2: The aims of this investigation were firstly, to determine the reliability of functional testing and the associated surface EMG signal on five consecutive days, and secondly to elucidate the reliability and precision of other dependent measures commonly used in the assessment of muscle damage following a bout of eccentric contractions. All variables displayed good reliability and therefore may be appropriate to examine longitudinal changes as a result of a damaging protocol. Study 3: The purpose of this investigation was to examine the magnitude of the repeated bout effect (RBE) from high and low volume maximal eccentric exercise followed by a high volume bout of maximal eccentric exercise after full recovery from the initial bout (two weeks later). There were no differences in dependent variables between groups in the repeated bout, indicating that the magnitude of the RBE is similar following initial low and high volume bouts of maximal eccentric exercise, which was attributable, at least in part, to changes in electromyographic frequency content. The initial high volume bout did however result in greater EIMD than the initial low volume bout; in addition, the magnitude of change from the initial bout was more profound after high volume exercise. Study 4: The aims of this investigation were to elucidate the existence of a contralateral RBE in the upper limb and to compare the magnitude of change to an ipsilateral model, which had been previously been established in Study 3. Significant differences in some variables provide evidence that a repeated bout effect is evident in the contralateral limb after a single bout of eccentric exercise. This adaptation appears to be mediated by neural mechanisms, as there is no direct stimulus for change from the initial bout to the contralateral homologous muscle group. The magnitude of change between contralateral and ipsilateral models was different for some variables suggesting that the RBE is not as profound in contralateral homologous muscle as in the ipsilateral model. These investigations provide additional novel data on interventions used to combat the negative effects of eccentric contractions and temporary EIMD. In particular, Study 4 has shown that adaptation occurs in the contralateral homologous muscle group, which has implications for a variety of populations and also for future research study design. Further investigations are warranted to elucidate the exact mechanisms responsible for the repeated bout effect.
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Gault, Mandy Lucinda. "Adaptations of older adults to concentric and eccentric endurance exercise." Thesis, University of Chichester, 2010. http://eprints.chi.ac.uk/813/.
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The first aim was to examine in older adults the acute physiological effects of eccentric exercise (i.e. downhill treadmill walking, DW: -10% gradient, 30-min) at a self-selected walking speed. The secondary aim was to examine in older adults the effects of a 12-week concentric (level treadmill walking, LW: 0% gradient) and eccentric (downhill treadmill walking, DW: -10% gradient) endurance exercise intervention (30-min, 3x week) at a self-selected walking speed (SSWS, re-evaluated every 4-weeks) on the functional and physiological adaptations. Participants were randomly assigned to an exercise group (LW: 0=13 or DW: n=IS). Eighteen participants (8 LWand 10 DW) completed the 12-week intervention. Wearing the Cosmed K4b2 portable metabolic system had no effect on performance and physiological responses during the I-mile Rockport Fitness Walking Test (Study I).
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Byrne, Christopher. "Muscle function after exercise-induced muscle damage." Thesis, Bangor University, 2001. https://research.bangor.ac.uk/portal/en/theses/muscle-function-after-exerciseinduced-muscle-damage(2bbf5fe1-f35b-4b7b-9790-ff3a04b86875).html.
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Muscle function after exercise-induced muscle damage has traditionally been evaluated by measures of isometric strength at a single joint angle or muscle length. The thesis investigates the effect of muscle damage on other muscle function parameters such as, isometric strength as a function of muscle length, concentric strength as a function of angular velocity, strength across muscle actions, the stretch-shortening cycle, power output, and fatigability. Study 1 The first part of this study aimed to determine how the muscle length at which strength is measured affects reductions in isometric strength following eccentric exercise-induced muscle damage. The damaging exercise protocol consisted of 100 maximal voluntary eccentric actions of the knee extensors, performed in the prone position through a range of motion from 40° to 140° (0° = full extension) at an angular velocity of 90 deg's-1. Isometric strength of the knee extensors was measured at short muscle length (10° knee flexion) and optimal length (80°). A significantly greater relative loss of strength was observed at short versus optimal muscle length (76.3 ± 2.5% vs. 82.1 ± 2.7% of pre-exercise values, P<0.05) over the seven day testing period following eccentric exercise. The second part of the study investigated isometric strength at optimal length and concentric strength at slow (30 deg's 1) and fast (180 deg's 1) angular velocities of movement. No differences were apparent in the magnitude and rate of recovery of strength across isometric (82.1 ± 2.7%) and slow (86.6 ± 2.0%) and fast (84.3 ± 1.5%) concentric muscle actions. Both the popping sarcomere hypothesis of 2 muscle damage and a failure in excitation-contraction coupling are possible explanations for the reduction in strength being affected by the muscle length at which it is measured. Both would be expected to affect strength to a greater extent at short versus optimal muscle lengths. Study 2 The second study investigated knee extensor muscle strength during isometric, concentric and eccentric muscle actions and vertical jump performance under conditions of squat jump (SJ), countermovement jump (CMJ) and drop jump (DJ). These measures were taken before, 1 hour after, and on days 1,2,3,4 and 7 following a damaging exercise protocol consisting of 100 barbell squats (10 sets x 10 reps @ 70% body mass load). Strength was significantly reduced for four days, however, no differences were observed in the magnitude or rate of recovery of isometric strength at 80° knee flexion and concentric and eccentric strength at 90 deg's'. Vertical jump performance was significantly reduced for three days and was dependent on the type of jump being performed. The relative decline in SJ performance was significantly greater than that in CMJ performance (91.6 ± 1.1% vs. 95.2 ± 1.3% of pre-exercise values, P<0.05) and the relative decline in SJ was significantly greater than that in DJ performance (91.6 ± 1.1% vs. 95.2 ± 1.4%, P<0.05). No differences were observed in the relative decline in CMJ and DJ performance (95.2 ± 1.3% vs. 95.2 ± 1.4%, P> 0.05). The stretch-shortening cycle (SSC) of muscle function is utilised in CMJ and DJ but not in SJ. The SSC has a clear purpose: to allow the final phase (concentric action) to take place with greater force or power output, as compared to the condition where the movement is initiated by a concentric action alone. 3 Utilisation of the SSC in performance seems to attenuate the detrimental performance effects of exercise-induced muscle damage. Study 3 The third and final study investigated the effects of exercise-induced muscle damage on maximal power output and knee extensor fatigability under isometric and dynamic conditions. Under isometric conditions, strength was assessed at 40° and 80° knee flexion and fatigability was assessed by a sustained 60s maximum voluntary contraction (MVC) at each joint angle. For dynamic conditions, maximum power output and fatigue were assessed during a maximal 30s cycle ergometer test. These measures were taken before, 1 hour after, and on days 1,2,3, and 7 following a damaging exercise protocol consisting of 100 eccentric squats (10 sets x 10 reps @ 80% concentric 1 RM). Isometric strength was significantly reduced (P < 0.05) for seven days but no significant differences were observed in the magnitude of strength loss and the pattern of recovery between the two joint angles. Fatigability was quantified as the slope (b) of a linear regression line fitted to the torque and power decay during the 60s MVC and the 30s cycle test, respectively. Prior to muscle damage, subjects were significantly less fatigable (P < 0.05) at 40° (b = -2.39 ± 0.26) versus 80° (b = -5.50 ± 0.72). After muscle damage, subjects became significantly less fatigable at both 40° and 80° with recovery taking three days at 401 and seven days at 80°. Before damaging exercise, a greater rate of fatigue was observed under dynamic (b = -12.75 ± 2.3) versus isometric (80°) conditions (b = -5.50 ± 0.72). Isometric and dynamic fatigue 4 followed a similar temporal pattern after damaging exercise. When the effects of muscle damage on strength at 801 and maximal power output were compared, differences in the extent of performance loss and the time course of recovery were observed. At 1 hour post-exercise, strength was affected to a greater extent (30% reduction) than power (13% reduction) and whereas strength followed a linear recovery pattern, power suffered further decrements at day 1 (18%) and day 2 (16%) before starting to recover. The results indicate that under conditions of voluntary activation muscle becomes weaker but less fatigable under isometric and dynamic conditions following exercise-induced muscle damage. The lower starting torque / power output and the slower rate of decline in torque / power output observed in post-damage fatigue curves may be a phenomenon of selective type II fibre damage. Evidence suggests that type II fibres are selectively damaged during eccentric exercise and therefore post-damage fatigue curves may be missing their contribution to performance. The different recovery patterns observed for isometric and dynamic performance may indicate an inability to maintain central motor drive during complex dynamic tasks when damage is present.
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Kudiarasu, Christine. "Effects of eccentric versus concentric resistance training in adults with Type 2 Diabetes." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2020. https://ro.ecu.edu.au/theses/2297.
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The benefits of resistance training for people with Type 2 diabetes (T2D) are well documented; however, the effects of different muscle contraction types (e.g. eccentric, concentric) on physiological outcomes for this population are still unclear. This study investigated the effects of eccentric (ECC) versus concentric (CON) resistance training on blood markers, muscle strength, physical functional performance and body composition. Eighteen adults with T2D (Age: 64.8 ± 9.0 y; BMI: 30.3 ± 4.1 kg/m2) were randomly assigned to either an ECC (n = 9) or a CON (n = 9) group. Participants performed 2 or 3 sets of 10 eccentric (5-s) or concentric (2-s) contractions of eight upper and lower body resistance exercises, twice a week for 12 weeks. Training intensity gradually increased from 10 to 100% of 1-repetition maximum concentric strength (1-RM) for the ECC group and from 50 to 100% of 1-RM strength for the CON group, based on the 1-RM at baseline. Blood markers (glucose, insulin, HbA1c, HOMA2-IR, cholesterol, triglycerides, HDL and LDL), muscle strength (1- RM), body composition (dual-energy x-ray absorptiometry), and physical functional performance tests consisting of 6-min walk (6MWT), chair rise (CR), timed up-and-go (TUG), and balance were measured before and after the intervention, and the changes were compared between groups. Significant differences in the improvement between the ECC and CON group were found for 1-RM strength for bicep curl (ECC: 11%, CON: 27%), calf raise (ECC: 37%, CON: 68%) and abdominal crunch (ECC: 22%, CON: 42%) exercises, hip circumference (ECC: -1%, CON: -5%) and SF-36 pain measures (ECC: 6%, CON: -1%). Muscle strength significantly increased more for the CON group (27–68%) than the ECC group (12–37%) which was likely due to greater combined total load lifted in the CON (143,262 ± 57,972 kg) than the ECC group (111,678 ± 51,225 kg). Significant improvements (p < 0.05) were also found in the ECC group for the 6MWT (56.8 ± 2.2 m), TUG (-0.8 ± 0.3 s) and CR (-1.8 ± 1.4 s), while the CON group significantly improved the 6MWT (63.4 ± 12.0 m) and CR (-2.3 ± 1.6 s). Total equilibrium balance increased by 7.0% in the ECC group and 4.3% in the CON group. Body composition improved similarly for both groups including significant reductions in total fat mass (ECC: -2.0 ± 1.3 kg, CON: -2.2 ± 1.2 kg) and significant increase in total lean mass (ECC: 1.8 ± 0.7 kg, CON: 2.0 ± 0.2 kg). No significant changes were found in blood markers for both groups. These results showed that ECC training performed at lower intensities (RPE: 4.1 ± 2.1) was as effective as CON training for improving physical functional performance, strength and body composition. These findings suggest that focusing on eccentric contractions in resistance training is beneficial and well-tolerated in adults with T2D.
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Miranda, Ana Areias Marques. "O efeito dos exercícios excêntricos na tendinopatia do tendão de Aquiles em adultos saudáveis: revisão sistemática." Bachelor's thesis, [s.n.], 2016. http://hdl.handle.net/10284/5674.
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Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciada em FisioterapiaObjetivo: A presente revisão pretende compreender os efeitos da implementação de exercícios excêntricos na tendinopatia do tendão de aquiles independentemente da amostra utilizada. Metodologia: Pesquisa computorizada através das palavras-chaves elegidas, em bases de dados como Science Direct, EBSCO e Pubmed para selecionar artigos experimentais que colocassem em questão a eficiência dos exercícios excêntricos na tendinopatia do tendão de aquiles. Resultados: Foram incluídos 12 artigos, com um total de 465 indivíduos. Obtendo uma média de 8,8 na escala CASP. 3 artigos compararam o uso de exercícios excêntricos com o uso de uma ortótese noturna, outros 3 compararam com outras técnicas terapêuticas e os restantes aplicaram apenas exercícios excêntricos. Conclusão: Após a analise dos resultados é possível observar a eficácia dos exercícios excêntricos na tendinopatia do tendão de aquiles, no entanto, muitas vezes não são diferenças que corresponderiam ao expectável. A aplicação de ortóteses e aprendizagem do método não potencia o efeito positivo, contudo associado a outras técnicas terapêuticas (ultrassom e massagem transversal profunda) promove a sua eficácia.
Objective: The present revision pretends to comprehend the effects of the implementation of eccentric exercises in the Achilles tendinopathy regardless the sample used. Methodology: Computer research through elected keywords, in data bases such as Science Direct, EBSCO and Pubmed to select experimental articles that would question the effectiveness of eccentric exercises in the Achilles tendinopathy. Results: Twelve articles were selected, with a total of 465 individuals. Obtaining an average of 8,8 in the CASP scale. 3 articles compared the use of eccentric exercises with the use of a night orthosis, other 3 compared with other therapeutic techniques and the rest only applied eccentric exercises. Conclusion: After the analysis of the results it is possible to observe the effectiveness of the eccentric exercises of the Achilles tendinopathy, however, many times the differences would not correspond to the expectable. The application of orthosis and the learning method do not enhance the positive effect, however in association with other therapeutic techniques (ultrasound and deep transversal massage) promotes its effectiveness.
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Fischer, Stephen Michael. "METABOLIC DIFFERENCES BETWEEN A BOUT OF ECCENTRIC, CONCENTRIC, AND TRADITIONAL RESISTANCE EXERCISE." Kent State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=kent1479465117642973.
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Wagle, John. "Kinetic and Kinematic Characteristics of Accentuated Eccentric Loading." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etd/3484.
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The current investigation was an examination of the kinetic and kinematic characteristics of the back squat using accentuated eccentric loading (AEL) and cluster set programming strategies. Trained male subjects (age = 26.1 ± 4.1 years, height = 183.5 ± 4.3 cm, body mass = 92.5 ± 10.5 kg, back squat to body mass ratio = 1.8 ± 0.3) volunteered to complete four different load condition sessions involving traditionally loaded straight sets (TL), traditionally loaded cluster sets (TLC), AEL cluster sets (AEC), and AEL straight sets where only the first repetition of each set used eccentric overload (AEL1). The use of AEL increased eccentric work (WECC) and eccentric rate of force development (RFDECC) but did not result in the expected potentiation of subsequent concentric output. Interrepetition rest, however, appears to have the largest influence on concentric peak power (PP), rate of force development (RFDCON), and average velocity (MV). Additionally, the current study was an investigation of the efficacy of novel methods of ultrasonography technique that can be applied to monitoring training response. Compared to lying measures of the vastus lateralis (VL), standing ultrasonography measures of muscle thickness (MT), pennation angle (PA), and cross-sectional area (CSA) were more strongly and abundantly correlated with dynamic and isometric strength performance. Finally, the present study was an exploration of the genetic underpinnings of performance outcomes and muscle phenotypic characteristics. The polymorphisms of two candidate genes (ACTN3, ACE) typical of strength-power athletes were used. ACTN3 RR tended to result in greater type II fiber CSA and alter maximal strength, while ACE DD tended to influence RFD through the presence of more favorable type II-to-type I CSA ratios. Overall, the current investigation provided valuable insight into the characteristics of advanced programming tactics. Furthermore, the ultrasonography measurement and genetic aspects of the current investigation may serve as a framework to inform monitoring practice and generate hypotheses related to the training process.
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Kim, Junghoon. "The influence of force production and eccentric exercise on growth hormone." Virtual Press, 1997. http://liblink.bsu.edu/uhtbin/catkey/1048386.
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The main purpose of this study was to investigate the relationship between human growth hormone (hGH) and two separate components of resistance exercise. Eight non-weight-trained subjects (23.33 ± 0.3 yrs) performed three force production trials (FPT), at different concentric workloads, and an 120% eccentric exercise trial (EET) on the Cybex 6000. Blood samples (3 mls) were taken pre- and post-exercise and analyzed for lactate, creatine kinase (CK) and hGH. Electromyographic (EMG) activity of the quadriceps muscle was recorded during each trial. The mean peak torque produced during the FPTs increased as work intensity increased but was the highest in the EET. The data for total work showed a proportional relationship with the intensity of the three concentric work loads but not the 120% EET. EMG activity of vastus medialis (VM) and rectus femoris (RF) measured during EET was 26% less than RF of 50% and 15% less than VL of 70% in FPT, respectively. The highest hormonal response occurred following the 120% EET. The hormonal response following the FPTs was highest in the 90% FPT with the two lower work intensity trials (50 and 70%) showing no clear hormonal response. Although the hGH response was the highest in the 120% EET, the post-exercise lactic acid levels in EET were 24% less than that of the 90% FPT. Creatine kinase (CK) activity was significantly elevated 36 hours after the last bout of EET which suggests that the eccentric exercise resulted in muscle damage. The results from concentric trials showed that muscle force generation, EMG, and lactic acid of the three different concentric trials were well correlated to the pattern of hGH secretion. However, only peak torque was consistent with the hGH response of the EET. The highest peak torque and hGH levels were achieved with eccentric exercise. The highest levels of fatigue, as a result of the combination of longer exercise time and overloading of the muscle during EET, may explain the higher hGH output. The muscle damage caused by the eccentric trial was enough to induce delayed onset of muscle soreness and may be the stimulus for the higher hGH output. The hGH response may facilitate repair of the muscular damage induced by eccentric exercise by promoting protein synthesis.School of Physical Education
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Kellis, Eleftherios. "Muscle activation and joint loading during isokinetic eccentric and concentric exercise." Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321116.
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Dixon, Claire, Laureen Holloway, Teresa Lee, Nick Lo, Janice Meier, and Darlene Reid. "Pain-enduring Eccentric Exercise for the Treatment of Chronic Achilles Tendinopathy." Irving K. Barber Learning Centre, 2006. http://hdl.handle.net/2429/89.
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Recorded by Eugene Barsky, Physiotherapy Outreach Librarian, UBCThis is a Systematic Review Presentation titled - "Pain-enduring Eccentric Exercise for the Treatment of Chronic Achilles Tendinopathy", created by Master of Physical Therapy Graduating Students, University of British Columbia - 2006, Presented on September 14-15, 2006 , Vancouver, BC, Canada
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Sharifnezhad, Ali. "Longitudinal adaptation of vastus lateralis muscle in response to eccentric exercise." Doctoral thesis, Humboldt-Universität zu Berlin, Philosophische Fakultät IV, 2014. http://dx.doi.org/10.18452/16918.
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In der vorliegenden Studie wurde daher den Einfluss exzentrischen Trainings, mit unterschiedlicher Reizmagnitude, Bewegungsgeschwindigkeit und Muskellänge bei Reizapplikation, auf die Adaptation des M. vastus lateralis (VL) untersucht. Die 31 Studienteilnehmer wurden randomisiert in zwei Trainings- und eine Kontrollgruppe aufgeteilt. Die Trainingsgruppen führten 30 Trainingseinheiten mit exzentrischem Training der Knieextensoren an einem Isokineten durch. Gruppe 1 (n=10) trainierte ein Bein mit 65% der maximalen willkürlichen isometrischen Kontraktion (MVC) und das andere Bein mit 100% MVC, bei einer Winkelgeschwindigkeit von 90°/s und einem Kniewinkel von 25°-100°. Gruppe 2 (n=10) trainierte beide Beine mit 100% MVC, ein Bein aber mit einer Winkelgeschwindigkeit von 90°/s in einem Kniewinkel von 25°-65° und das andere Bein mit 240°/s und 25°-100°. In der Pre- und Postmessung wurde die VL Muskelfaserlänge mittels Ultraschall bestimmt und die Moment-Winkel- und Leistungs-Winkelgeschwindigkeitsrelation mit einem Dynamometer erfasst. Die Ergebnisse zeigen nur für Bein mit 240°/s eine signifikante (pThe present study investigated the effects of magnitude, velocity and muscle length at which the eccentric stimulus is applied on the longitudinal adaptation of the vastus lateralis muscle (VL). The 31 participants were randomly assigned into two experimental groups to perform 30 sessions of eccentric training for the knee extensors (3 times/week) and one control group. The first experimental group (n=10) exercised one leg at 65% of maximum voluntary isometric contraction (MVC) and the second leg at 100% MVC at 90°/s from 25° to 100° knee angle on an isokinetic device (Biodex 3). The second experimental group (n=10) exercised one leg at 100% MVC at 90°/s from 25° to 65° knee angle and the other leg at 100% MVC at an angular velocity of 240°/s from 25° to 100° knee angle. In pre and post measurements the fascicle length of the VL was examined by ultrasonography and the moment-angle and power-angular velocity relationship of the knee extensors with a dynamometer. The results showed an increase (p
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Larsson, Claes, and Ljunggren Oscar Wallén. "Skadeförebyggande träningsmetoder mot hamstringsskador inom svensk herrelitfotboll i jämförelse med rekommenderad evidensbaserad forskning." Thesis, Högskolan Dalarna, Idrotts- och hälsovetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:du-22622.
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Purpose The purpose of this study was to describe the evidence-based research recommendations on injury prevention methods against hamstring injuries among Swedish men's elite team in football. The research-based recommendations was then to be compared with the way Swedish elite football teams work to prevent hamstrings injuries. Method First a literature search of PubMed and SPORTDiscuss was made to find the most evidence-based training methods to hamstring injuries. Then an Internet questionnaire regarding injury prevention training methods against hamstring injuries was sent to all Swedish elite football teams. The answers off the questionnaire was then compared with the research that had the most evidence based training methods to hamstring injuries. Results Research shows that the method with the most evidence is eccentric strength training. Flexibility, static stretch and core stability training is research methods that can be used to prevent hamstrings injuries but these methods lack a large validated research basis. 8 of 32 (25 %) teams answered the questionnaire. All teams indicated that they were working with injury prevention methods but the methods varied from the eccentric strength training to periodization and flexibility training. 2 of 8 teams indicated that they worked with eccentric strength training that is recommended by science as the most evidence-based training method. Conclusion The study shows that the teams partly work after what the research recommends as the most evidence-based training methods against hamstring injuries. However, the study lacks validity and further research is needed before definitive conclusions can be drawn.Syfte Syftet med denna studie är att beskriva vilka evidensbaserade forskningsrekommendationer som finns kring skadeförebyggande träningsmetoder mot hamstringsskador hos svenska herrelitlag i fotboll. De forskningsbaserade rekommendationerna ska sedan jämföras med arbetssättet hos herrelitlagen i svensk fotboll. Metod Först gjordes en litteratursökning på databaserna PubMed och SPORTDiscuss för att hitta de mest evidensbaserade träningsmetoderna mot hamstringsskador. Sedan skickades en webbenkät angående skadeförebyggande träningsmetoder mot hamstringsskador ut till alla svenska herrelitfotbollslag. Svaren på enkäten speglades sedan mot vad forskningen rekommenderade som de mest effektiva träningsmetoderna mot hamstringsskador. Resultat Forskning visar att den metoden med mest evidens är excentrisk styrketräning. Rörelse/stretch samt bålstabilitetsträning är enligt forskningen metoder som kan användas för att förebygga hamstringsskador men dessa metoder saknar ett stort validerat forskningsunderlag. 8 av 32 (25%) föreningar besvarade enkäten. Alla föreningar angav att de arbetade med skadeförebyggande åtgärder men metoderna varierade från excentrisk styrketräning till periodisering och rörlighetsträning. 2 av 8 föreningar angav att de arbetade med excentrisk styrketräning som forskningen rekommenderar som den mest evidensbaserade träningsmetoden. Slutsats Studien visar att föreningarna delvis arbetar efter vad forskningen rekommenderar som evidensbaserade träningsmetoder mot hamstringsskador. Dock saknar studien validitet och ytterligare forskning behövs för att slutgiltiga slutsatser ska kunna dras.
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Seger, Jan Y. "Neuromuscular aspects of eccentric knee extensor actions : effects of electrical stimulation, age, gender and training /." Stockholm, 1998. http://diss.kib.ki.se/1998/91-628-3200-X/.
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Grose, George Sebastian. "The effect of exercise-induced fatigue and eccentric muscle damage on kinaesthesia." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61726.
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The senses of position and movement are known collectively as kinaesthesia. Muscle spindles are length sensitive receptors, considered pivotal to these senses. Mechanical muscle vibration artificially stimulates muscle spindles and this can lead to illusory limb postures and movements, thereby disrupting kinaesthesia. Exercise induced fatigue also impairs kinaesthesia and this impairment persists if the exercise involves lengthening contractions that create eccentric muscle damage. It is not entirely clear why these lasting impairments occur. Using a targeted movement sequence with the unseen arm (a task that relies heavily on muscle spindles), this study utilized a novel paradigm to investigate task performance both before and after an eccentric based exercise protocol. By investigating the influence of vibration applied to the involved musculature, the results provide insight into how exercise acutely disrupts kinaesthesia. It was found that mechanical muscle vibration created a robust effect on task accuracy at all points during the study, causing participants to undershoot the targets (as previously described in the literature). The effects of exercise also caused a consistent error in task performance, but did not appear to influence the effect of vibration. This suggests that the nervous system continues to rely heavily on muscle spindles, even when they reside in a muscle exposed to damaging eccentric contractions.Education, Faculty of
Kinesiology, School of
Graduate
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Balshaw, Thomas G. "Acute neuromuscular, kinetic, and kinematic responses to accentuated eccentric load resistance exercise." Thesis, University of Stirling, 2013. http://hdl.handle.net/1893/17174.
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Neurological and morphological adaptations are responsible for the increases in strength that occur following the completion of resistance exercise training interventions. There are a number of benefits that can occur as a result of completing resistance exercise training interventions, these include: (i) reduced risk of developing metabolic health issues; (ii) decreased risk and incidence of falling; (iii) improved cardiovascular health; (iv) elevated mobility; (v) enhanced athletic performance; and (vi) injury prevention. Traditional resistance exercise (constant load resistance exercise (CL)) involves equally loaded eccentric and concentric phases, performed in an alternating manner. However, eccentric muscle actions have unique physiological characteristics, namely greater force production capacity and lower energy requirements, compared to concentric actions. These characteristics have led to the exploration of eccentric-focused resistance exercise for the purposes of injury prevention, rehabilitation, and enhancement of functional capacity. Accentuated eccentric load resistance exercise (AEL) is one form of eccentric-focused resistance exercise. This type of resistance exercise involves a heavier absolute external eccentric phase load than during the subsequent concentric portion of a repetition. Existing training study interventions comparing AEL to CL have demonstrated enhancements in concentric, eccentric, and isometric strength with AEL. However, no differences in strength adaptations have been reported in other AEL vs. CL training studies. Only 7 d intensified AEL training interventions have measured neuromuscular variables, providing evidence that enhanced neuromuscular adaptations may occur when AEL is compared to CL. Therefore, a lack of information is currently available regarding how AEL may differentially affect neuromuscular control when compared to CL. Furthermore, the equivocal findings regarding the efficacy of AEL make it difficult for exercise professionals to decide if they should employ AEL with their athletes or patients and during which training phase this type of resistance exercise could be implemented. Therefore, the aims of this thesis were: (i) to examine differences in acute neuromuscular, kinetic, and kinematic responses between AEL and CL during both lower-body single-joint resistance exercise and multiple-joint free weight resistance exercise; (ii) to assess acute force production and contractile characteristics following AEL and CL conditions; (iii) to investigate the influence of eccentric phase velocity (and time under tension) on acute force production and contractile characteristics following AEL and CL conditions; and (iv) to compare common drive and motor unit firing rate responses after single- and multiple-joint AEL and CL. Before investigating neuromuscular, kinetic, and kinematic responses to AEL it was deemed necessary to evaluate normalisation methods for a multiple-joint free weight resistance exercise that would permit the implementation of AEL. Therefore, the aim of the first study of the thesis was to evaluate voluntary maximal (dynamometer- and isometric squat-based) isometric and submaximal dynamic (60%, 70%, and 80% of three repetition maximum) electromyography (EMG) normalisation methods for the back squat resistance exercise. The absolute reliability (limits of agreement and coefficient of variation), relative reliability (intraclass correlation coefficient), and sensitivity of each method was assessed. Strength-trained males completed four testing sessions on separate days, the final three test days were used to evaluate the different normalisation methods. Overall, dynamic normalisation methods demonstrated better absolute reliability and sensitivity for reporting vastus lateralis and biceps femoris EMG compared to maximal isometric methods. Following the methodological study conducted in Chapter 2, the next study began to address the main aims of the thesis. The purpose of the third chapter of the thesis was to compare acute neuromuscular, kinetic, and kinematic responses between single-joint AEL and CL knee extension efforts that included two different eccentric phase velocities. Ten males who were completing recreational resistance exercise attended four experimental test day sessions where knee extension repetitions (AEL or CL) were performed at two different eccentric phase velocities (2 or 4 s). Elevated vastus lateralis eccentric neuromuscular activation was observed in both AEL conditions (p= 0.004, f= 5.73). No differences between conditions were detected for concentric neuromuscular or concentric kinematic variables during knee extension efforts. Similarly, no differences in after-intervention rate of torque development or contractile charactersitics were observed between conditions. To extend the findings of the third chapter of the thesis and provide mechanistic information regarding how AEL may differentially effect acute neuromuscular variables that have been reported to be undergo chronic adaptations, additional measures that were taken before and after the intervention described in the previous chapter were analysed. Therefore, the purpose of the fourth chapter of the thesis was to compare motor unit firing rate and common drive responses following single-joint AEL and CL knee extension efforts during a submaximal isometric knee extension trapezoid force trace effort. In addition, motor unit firing rate reliability during the before-intervention trapezoid force trace efforts was assessed. No differences in the maximum number of detected motor units were observed between conditions. A condition-time-point interaction effect (p= 0.025, f= 3.65) for firing rate in later-recruited motor units occurred, with a decrease in firing rate observed in after-intervention measures in the AEL condition that was completed with a shorter duration eccentric phase. However, no differences in common drive were detected from before- to after-intervention measures in any of the conditions. The time period toward the end of the plateau phase of before-intervention trapezoid force trace efforts displayed the greatest absolute and relative reliability and was therefore used for motor unit firing rate and common drive analysis. The purpose of the fifth chapter was to compare acute neuromuscular and kinetic responses between multiple-joint AEL and CL back squats. Strength-trained males completed two experimental test day sessions where back squat repetitions (AEL or CL) were performed. Neuromuscular and kinetic responses were measured during each condition. No differences in concentric neuromuscular or concentric kinetic variables during back squat repetitions were detected between conditions. Elevated eccentric phase neuromuscular activation was observed during the AEL compared to the CL condition in two to three of the four sets performed for the following lower-body muscles: (i) vastus lateralis (p< 0.001, f= 15.58); (ii) vastus medialis (p< 0.001, f= 10.77); (iii) biceps femoris (p= 0.003, f= 6.10); and (iv) gluteus maximus (p= 0.001, f= 7.98). There were no clear differences in terms of the neuromuscular activation contributions between muscles within AEL or CL conditions during eccentric or concentric muscle actions. Following the investigation of acute motor unit firing rate and common drive responses to lower limb single-joint AEL and CL in the fourth chapter of the thesis, the question arose as to whether or not similar responses would occur in a more complex model, such as a multiple-joint resistance exercise. Multiple-joint resistance exercise poses different neuromuscular activation, coordination, and stabilisation demands. Therefore, the purpose of the sixth chapter of the thesis was to compare acute motor unit firing rate and common drive responses following multiple-joint lower-body free weight AEL and CL.
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Doyle, James Andrew. "The effect of eccentric exercise on the rate of muscle glycogen synthesis /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487694389393968.
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Swanson, Scott Carl. "Muscle glycogen concentrations, GLUT4 and muscle damage in humans following eccentric exercise /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487942476407478.
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Kennedy, Paul. "Magnetic resonance elastography studies of human skeletal muscle." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25776.
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A robust, reliable method to non-invasively measure in-vivo mechanical properties of large tissue areas was unavailable until the advent of a new Magnetic Resonance Imaging (MRI) technique known as Magnetic Resonance Elastography (MRE). MRE is a phase-contrast imaging technique that enables quantification of tissue mechanical properties by capturing the motion of induced shear waves via a synchronised Motion Encoding Gradient (MEG). The complex shear modulus is determined via mathematical inversion and reported as the magnitude of the complex shear modulus, |G*|, and phase angle, φ. The work reported in this thesis focuses on the development of MRE data acquisition and analysis protocols optimised to study thigh muscle mechanical properties. The protocols are subsequently applied in healthy volunteers to study natural phenomena such as contraction and ageing and interventions such as an experimental protocol to produce Exercise Induced Muscle Damage (EIMD). Methodological advances made throughout this work include moving from 2D to 3D MRE data acquisition protocols and the application of advanced inversion software to extract muscle viscoelastic properties from the acquired MRE data. Results obtained include observation of reduced muscle stiffness in 6 elderly subjects (>80 years old) compared to 4 young subjects in the Vastus Lateralis (32%), quadriceps muscle group (22%) and entire thigh cross-section (19%), higher resting stiffness of agonist quadriceps compared to antagonist hamstrings (18%) and an increase in quadriceps stiffness (40%) during a leg raise task in 11 healthy subjects. Variability in muscle group recruitment patterns during the contraction were also observed, with the phase angle of the Vastus Intermedius (VI) increasing significantly during contraction. The final experiment involved the recruitment of 20 healthy male subjects to perform an eccentric exercise protocol designed to induce EIMD. Subjects who displayed a Maximum Voluntary Contraction (MVC) force deficit of >10% were considered to have experienced EIMD. A further severe EIMD group were defined based on the presence of hyper-intense signal on T2 weighted imaging following the protocol. The T2 hyper-intensity was found to occur exclusively in the Rectus Femoris (RF) and VI muscle groups. Increased muscle stiffness was observed in the RF muscle in subjects who experienced moderate EIMD (6%). A greater increase in RF stiffness (48%) was observed in the severe EIMD group. The severe EIMD group also displayed significantly increased VI stiffness (14%). The experiments carried out provide several novel findings which can support the development of beneficial strategies to promote both healthy ageing and rehabilitation in athletes, and potentially contribute to improving muscle performance evaluation tests which will expand the opportunities for clinical applications of muscle MRE.
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Joyce, Sarah M. "The Role of Oral Contraceptives and Gender in the Responses to Eccentric Resistance-Exercise and Cycling Performance." Thesis, Griffith University, 2013. http://hdl.handle.net/10072/365240.
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The primary aim of this thesis was to investigate the effect of gender and oral contraceptive use on the responses to eccentric resistance-exercise and endurance-exercise performance. The results of the three experiments conducted to achieve this aim are presented in this thesis. All subjects included in the present experiments were recreationally active individuals (exercised > 3 d·wk-1 for 30 min·session-1) that did not participate in regular cycling exercise or regular resistance-exercise training.
The aim of experiment one was to examine the effect of long-term oral contraceptive use on endurance-exercise performance in recreationally-active women. Eight normally-menstruating women, not taking oral contraceptives (WomenNM) and eight women taking oral contraceptives (WomenOC) performed an incremental cycling test to determine peak O2 uptake and to estimate the anaerobic threshold (AnT). Subjects also completed a continuous submaximal cycling test across three work stages (two 6 min work stages performed below the AnT, and one work stage performed above the AnT to exhaustion). Pulmonary gas exchange, heart rate, blood pressure, blood lactate concentration ([La-]), and rate of perceived exertion were measured throughout, and cycling economy was calculated. Physical characteristics were comparable between the groups (p > 0.05). Peak O2 uptake (WomenNM, 2.59 ± 0.50 L·min-1; WomenOC, 2.13 ± 0.20 L·min-1) and O2 uptake at the AnT (WomenNM, 1.47 ± 0.27 L·min-1; WomenOC, 1.18 ± 0.15 L·min-1) were significantly different between the groups (p < 0.05).Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Physiotherapy and Exercise Science
Griffith Health
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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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Andring, Jan Marie. "The consistency of inflammatory responses and muscle damage to high-force eccentric exercise." Thesis, Montana State University, 2006. http://etd.lib.montana.edu/etd/2006/andring/AndringJ0506.pdf.
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Weerakkody, Nivan Sargara. "Measurements of muscle pain, force matching ability and muscle adaptation after eccentric exercise." Monash University, Dept. of Physiology, 2003. http://arrow.monash.edu.au/hdl/1959.1/9561.
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Renwick, Nicholas Craig. "Eccentric stepping exercise : acute and chronic physiological responses in young and older adults." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/21974/.
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In comparison to concentric exercise, eccentric exercise allows an individual to achieve high mechanical loads for a lower cardiovascular and metabolic requirement. This highlights it as a possible efficacious rehabilitation intervention for exercise intolerant clinical populations, likely stimulating increases in strength and mobility without the development of exercise limiting symptoms that commonly present during traditional exercise. However, the majority of research utilises unnatural forms of eccentric exercise (i.e. reverse cycling), potentially restricting the compliance and translational benefits. Therefore, we have adapted an eccentric stepping ergometer, that may more closely replicate natural activity, and investigated the acute physiological responses and training adaptations within a young and older adult population. The ergometer adaptations enabled tight control of exercise parameters, and crucially allowed comparison of concentric and eccentric physiological responses on the same device. Consistent with previous literature, we demonstrated a lower eccentric oxygen uptake (V̇O2), heart rate (HR) and blood pressure (BP) at the same power, and a greater eccentric power required to match for concentric metabolic requirement. Interestingly, eccentric V̇O2 and HR progressively increased above a predicted steady state, suggesting a higher exercise intensity at this metabolic rate. Subsequently, we compared concentric and eccentric training within young adults at similar mechanical and metabolic requirements, showing that higher eccentric powers were required to match for concentric V̇O2 and resulted in substantial increases in concentric, eccentric, and isometric strength, not seen with concentric training. Finally, we assessed the feasibility of a short eccentric recumbent stepping programme within an older adult population, showing considerable increases in concentric, eccentric and isometric strength that were maintained at 30-days follow up. Importantly, within both populations, the exercise remained tolerable and resulted in minimal muscle soreness. These results provide further evidence to support the beneficial neuromuscular adaptions of eccentric exercise, and suggest that eccentric recumbent stepping may provide a safer, more tolerable and effective training modality. Pilot studies with additional measures of physiological function (specifically muscle oxidative capacity and fatigue) suggest that eccentric exercise may promote additional benefits beyond those reported in this thesis. It is hoped that the findings from this thesis will eventually contribute to the implementation of eccentric exercise within exercise intolerant populations that stand to benefit most.
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Kelley, Joshua Jed. "Maintaining Skeletal Muscle Through Eccentric Exercise after Bariatric Surgery: A Randomized Controlled Trial." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7742.
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Purpose: To investigate the effects of eccentric exercise on lower body skeletal muscle mass during rapid body mass loss induced by bariatric surgery. Methods: All participants began 6 to 8 weeks after undergoing Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Skeletal muscle mass (SMM) in the lower body was measured via magnetic resonance imaging (MRI); additional exercise measurements included muscular strength and functional capacity. Quality of life was measured using Short Form 36 (SF-36). Nineteen females (age = 37.6 ± 9.8 yr, height = 164.4 ± 7.2 cm, mass = 106.9 ± 15.6 kg) were randomly assigned to 1 of 3 groups: eccentric exercise (EEX; n = 6), concentric exercise (CEX; n = 7), or standard-of-care control (CON; n = 6). Exercise groups performed 30-minute lower-body exercise sessions 3 times per week for 16 weeks. Each month the exercise tests were evaluated. At the end of 16 weeks, all participants performed the final exercise tests, received a final MRI scan, and completed the SF-36 questionnaire. Results: Thirteen individuals completed the study. All groups lost mass: CON: 21.4 ± 3.7 kg (p < 0.001), CEX: 19.9 ± 4.0 kg (p = 0.001), and EEX: 21.8 ± 3.3 kg (p < 0.001). SMM decreased in all groups: CON: 0.77 ± 0.5 kg (p = 0.18), CEX: 1.19 ± 0.6 kg (p = 0.06), and EEX: 0.90 ± 0.5 kg (p = 0.09). The skeletal muscle loss in percent of total mass loss was 3.7 ± 4.1%. All measures of muscular strength showed no difference, except for a small decrease in dynamic (60°·sec-1) strength in the eccentric group. Functional capacity and physical quality of life increased significantly in all groups (p < 0.05). Conclusion: SMM loss still occurred in the lower body regardless of resistance training, but the loss was less than what was previously documented. Improved postsurgical functional capacity and physical quality of life may be due to a reduction in fat mass and maintenance of muscular strength during the period of rapid mass loss.
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Wagle, John P., Christopher B. Taber, Aaron J. Cunanan, Garett E. Bingham, Kevin M. Carroll, Brad H. DeWeese, Kimitake Sato, and Michael H. Stone. "Accentuated Eccentric Loading for Training and Performance: A Review." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etsu-works/4649.
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Accentuated eccentric loading (AEL) prescribes eccentric load magnitude in excess of the concentric prescription using movements that require coupled eccentric and concentric actions, with minimal interruption to natural mechanics. This method has been theorized to potentiate concentric performance through higher eccentric loading and, thus, higher concentric force production. There is also evidence for favorable chronic adaptations, namely shifts to faster myosin heavy chain isoforms and changes in IIx-specific muscle cross-sectional area. However, research concerning the acute and chronic responses to AEL is inconclusive, likely due to inconsistencies in subjects, exercise selection, load prescription, and method of providing AEL. Therefore, the purpose of this review is to summarize: (1) the magnitudes and methods of AEL application; (2) the acute and chronic implications of AEL as a means to enhance force production; (3) the potential mechanisms by which AEL enhances acute and chronic performance; and (4) the limitations of current research and the potential for future study.
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Niesen-Vertommen, Sherri. "The effect of an eccentric-type exercise versus a concentric-type exercise in the management of chronic Achilles tendonitis." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/28144.
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The main purpose of this study was to determine which method of tendon rehabilitation - the "eccentric ankle drop" exercise or the universal gym "concentric plantarflexion/dorsiflexion" exercise - produced a more effective result in terms of recovery in the treatment of chronic Achilles tendonitis.
Seventeen subjects with chronic Achilles tendonitis were studied. They were selected on the basis that they had a history of athletic participation, and have had the symptoms of Achilles tendonitis greater than three weeks.
Subjects were assigned to either of two groups: training using the "eccentric ankle drop" exercise or training using the "concentric plantarflexion/ dorsiflexion" exercise. Subjects were clinically examined by a physician and referred to the study, then placed on a twelve week exercise program. They were examined and tested at 0, 4, 8 and 12 weeks. Testing included the following variables: average and peak torque measured on the KIN/COM Isokinetic Dynamometer at 3 0 and 50 degrees per second, and for plantarflexor concentric and eccentric muscle contractions, a subjective evaluation of pain and return to activity rated on a scale from 1 to 10.
The results showed the "eccentric ankle drop" exercise did not significantly increase in average or peak torque values at either velocity of 3 0 or 50 degrees per second more so than the "concentric plantarflexion/dorsiflexion" exercise. However, the eccentric group did demonstrate larger gains in both torque value compared to the concentric group. The plantarflexor torque values on the whole increased in a linear fashion at both velocities for both groups similarly, as indicated by the highly significant trend analysis (p<.001). There was a significant difference seen in pain ratings between the groups averaged over the four testing sessions (p<.01) with the eccentric group decreasing in pain more than the concentric group. Also, the eccentric exercise group produced three times as many "pain free" subjects at the end of the program than the concentric group. There was not a significant difference observed between the eccentric exercise group and the concentric exercise group with the return to activity effect. However the eccentric group over the twelve week period demonstrated a quicker return to preinjury activity than did the concentric group. The eccentric group also produced four times as many full return to preinjury activity level subjects by the end of the program than did the concentric group. Also the return to activity effect increased in a linear fashion for both groups similarly, as indicated by the highly significant trend analysis (P<.001).
Although no statistical significance was found between the two exercise groups (except for pain levels), the subjective measures favor the use of the eccentric exercise. Thus from a clinical standpoint, the eccentric exercise can be recommended as a more positive approach toward the conservative management of chronic Achilles tendonitis.Education, Faculty of
Curriculum and Pedagogy (EDCP), Department of
Graduate
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Lipski, Marcin. "High-intensity interval eccentric cycling: Acute and chronic effects." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2018. https://ro.ecu.edu.au/theses/2104.
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Eccentric cycling training has been prescribed in continuous and low intensities protocols, based on concentric cycling parameters. While the lower metabolic demand of eccentric than concentric cycling is advantageous for clinical or ‘at-risk’ populations, it is a disadvantage for cardiovascular and pulmonary adaptations. High-intensity interval protocols may increase both, strength and endurance. Thus, this research project compared i) an incremental concentric and eccentric cycling test until exhaustion for the relationship between power output and physiological parameters
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Serravite, Daniel H. "Whole Body Periodic Acceleration Reduces Levels of Delayed Onset Muscle Soreness After Eccentric Exercise." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/650.
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Context: Several recovery strategies have been used, with limited effectiveness, to reduce the muscle discomfort or pain and the diminished muscle performance following a bout of unaccustomed physical activity, a condition known as delayed onset of muscle soreness (DOMS). Muscle damage in this condition is associated with mechanical disruption of the muscle and connective tissue and inflammation and increased oxidative stress. Low frequency, low intensity, whole body periodic acceleration (WBPA) that increases nitric oxide (NO) release from vascular endothelium into the circulation through increased pulsatile shear stress offers a potential solution. This is because endothelial derived nitric oxide has anti-inflammatory, antioxidant and anti-nociceptive properties. Objective: The purpose of this study was to examine the effects of WBPA on the pain and diminished muscle performance associated with DOMS induced by unaccustomed eccentric arm exercise in young male subjects. Design: Longitudinal. Setting: University Exercise Physiology Laboratory. Participants: Seventeen active men, 23.4 +/- 4.6 yr of age. Intervention: Subjects made six visits to the research facility over a two-week period. On day one, the subject performed a 1RM elbow flexion test and was then randomly assigned to the WBPA or control group. Criterion measurements were taken on Day 2, prior to and immediately following performance of the eccentric exercise protocol (10 sets of 10 repetitions using 120% of 1RM) and after the recovery period. During all subsequent sessions (24, 48, 72, and 96 h) these data were collected before the WBPA or passive recovery was provided. Main Outcome Measures: Isometric strength (MVC), blood markers (CPK, MYO, IL-6, TNF-alpha and Uric Acid), soreness, pain, circumference, and range of motion (ROM). Results: Significantly higher MVC values were seen for the WBPA group across the entire 96 h recovery period. Additionally, within group differences were seen in CPK, MYO, IL-6, soreness, pain, circumference, and ROM showing a smaller impact and more rapid recovery by the WBPA group. Conclusion: Application of WBPA hastens recovery from DOMS after eccentric exercise. Given the lack of other potential mechanisms, these effects appear to be mediated by the increased NO release with WBPA.
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Miller, James A. L. "The nature and formation of muscle inflammation after eccentric exercise damage and in polymyositis." Thesis, University of Birmingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403903.
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Newton, Michael John. "The Relationship Between Functional And Histological Changes In Muscle Following Eccentric Exercise In Mice." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2000. https://ro.ecu.edu.au/theses/1529.
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Exercise-induced muscle damage (EIMD) is known to be produced by novel or unaccustomed exercise, especially high force eccentric contractions. Histological myofibre disruption, force loss and muscle soreness are associated with EIMD and have implications for sporting performance. Traditional practices of assessing the extent of disruption to the myofibres is by performing needle biopsies and subsequently analysing the histology of the fibres. Recently there has been interest in investigating whether changes in force production and contractile properties of muscle following damaging exercise correlate strongly with the magnitude of disruption to the myofibres. The main aim of this study was to investigate whether changes in force production and contractile properties of muscle following damaging eccentric exercise correlated with myofibre disruption. In order to test the hypotheses set down in the study 56 mice (C57 BU/10 strain) were randomly assigned to two groups (active and passive). Each main group was then divided into 5 subgroups. Anaesthetised mice performed either 120 active (eccentric contractions) or passive (no muscle contraction) lengthening repetitions after which they were allowed to recover. The right foot was fixed to a foot plate housing a force transducer which was directly attached to the axle of a stepping motor. A stimulating electrode was surgically placed around the peroneal nerve and P. and 1/ 150 Hz ratios were determined. Animals in the active group then performed 5 bouts of 24 stimulated lengthening repetitions at 0.3 amps with a stimulation frequency of IOO Hz. The passive group's protocol was identical with the exception that no stimulation was provided. One repetition for both active and passive groups consisted of a 300 millisecond plantar flexion movement of the foot plate and a 4.7 second dorsi flexion recovery movement to the starting position. Active and passive subgroups were terminated at 3, 6, 10, 15 and 20 days following exercise, prior to which P. and 1/ 150 Hz ratio were determined. Tibialis anterior (TA) muscles were excised at this time from both exercised and contralateral limbs and prepared for later histological examination. Significant differences were evident between the two groups for Po following each bout of 24 lengthening repetitions, 10 minutes following lengthening and on days 3 and 20 of recovery. The only significant differences between the groups in 1/ 150 Hz ratio occurred 10 minutes following lengthening and at day six of recovery (p
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Zainuddin, Zainal A. "The effects of movement based interventions on DOMS and muscle damage following eccentric exercise." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2004. https://ro.ecu.edu.au/theses/1647.
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Delayed onset muscle soreness (DOMS) is a common symptom experienced by most adults following unaccustomed exercise. It is known that DOMS is peculiar to eccentric exercise that results in muscle damage which is characterized by prolonged loss of muscle function. DOMS and subsequent impaired muscle function, reduces the ability to maximize performance of daily living tasks, and has negative effects on sports adherence and activity based healthy lifestyle. Thus, treatments to ameliorate DOMS and enhance recovery of muscle function are important.
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Lau, Wing Y. "Effect of vibration treatment on symptoms associated with eccentric exercise-induced muscle damage [thesis]." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2008. https://ro.ecu.edu.au/theses/169.
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Unaccustomed eccentric exercise results in delayed onset of muscle soreness (DOMS), loss of muscle strength, reduced range of motion (ROM) and swelling. Vibration treatment has been used in physiotherapy to reduce pain and oedema, and to facilitate the repair of injured tissue. This study tested the hypothesis that vibration treatment would reduce the symptoms of muscle damage such as DOMS and swelling and enhance recovery from muscle damage induced by eccentric exercise. Each arm of 15 young men (24 +/- 3.8 yrs) performed 10 sets of 6 maximal eccentric contractions of the elbow flexors separated by 4 weeks in a counterbalanced order. One arm received a 30-minute vibration treatment at 30 minute, 1, 2, 3, and 4 days after exercise, and the other arm did not receive the treatment and was used as the control. Criterion measures consisted of maximal voluntary isometric and isokinetic strength of the elbow flexors, elbow joint angles and range of motion (ROM), upper arm circumference, muscle thickness by B-mode ultrasonography, muscle soreness, pressure pain threshold, and blood markers or muscle damage and inflammation. These measurements except for the blood measures were taken 1 day and immediately prior to exercise, and immediately, 1 hour, and 1, 2, 3, 4, 5 and 7 days after exercise. Blood samples were taken immediately before and 4 days after exercise. To examine acute effects of the treatment, changes in the measures before and immediately after each treatment session were analyzed by a Student t-test. Changes in the measures over time were compared between arms by a two-way repeated measures ANOVA with a Tukey's post-hoc test. The results showed that compared with the control condition, the treatment condition showed significantly (P<0.05) less development and faster disappearance of muscle soreness. ‘Peak’ muscle soreness after exercise occurred 1-3 days following exercise and was 18-30% less for the treatment than the control condition, and muscle soreness disappeared completely 4 days after exercise for the treatment condition, but this was not the case for the control condition. The recovery of ROM was significantly (P<0.05) faster for the treatment condition compared with the control condition; however, no significant effects of the treatment on the recovery of muscle strength was found. Immediately after the vibration treatment, a significant (P<0.05) reduction in muscle strength and muscle soreness, an increase in pressure pain threshold and ROM, and a decrease in upper arm circumference were evident. In conclusion, these results show that the 30- minute vibration treatment was effective for attenuation of DOMS and recovery of ROM following strenuous eccentric exercise. It also provides an analgesic effect, and is effective for alleviating DOMS, and has positive effects on enhancing recovery from muscle damage. Therefore, the vibration treatment is considered as an effective intervention for DOMS and symptoms associated with eccentric exercise-induced muscle damage.
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MacDonalds, Christopher, Kimitake Sato, Christian Carter, Hugh Lamont, William Sands, Michael H. Stone, Michael Israetel, et al. "Differences in sEMG Between Normal Squats and Accentuated Eccentric Loaded Squats in Competitive Collegiate Weightlifters." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etsu-works/3976.
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The purpose of the present work was to compare the effect of accentuated eccentric loaded (AEL) squats to normally loaded (NOR) squats on surface measured muscle activation (sEMG) in competitive weightlifters. Eight experienced, competitive weightlifters (six males, two females) completed both an AEL and NOR squat session (seven days apart), comprised of nine sets of squats, and was identical to their normal scheduled training. sEMG data from the vastus medialis (VM), vastus lateralis (VL), and biceps femoris (BF) was collected (at 1000Hz) during the entirety of the concentric (CON) phases of the AEL and NOR sessions. RMANOVAs (set x session-type) were calculated and no statistical differences were found (p > 0.05) while promising statistical effect sizes (?2 partial 0.073 to 0.273) were observed.
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Brughelli, Matt. "Risk factors, assessments and prevention of muscle strain injuries." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2009. https://ro.ecu.edu.au/theses/1908.
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The relationships between mechanical stiffness, eccentric exercise and muscle strain injury are emerging areas of interest to researchers. For example, asymmetries between lower body limbs during athletic movements (i.e. ground reaction forces or mechanical stiffness) are thought to increase the risk of injury and compromise performance. The first two chapters of this PhD reviewed the literature on the topics of mechanical stiffness, and the effects of eccentric exercise on optimum length for force development. Both chapters included implications for muscle strain injuries. The third chapter reviewed the previous literature that has investigated the effects of eccentric exercise on hamstring injury rates. The interventions used were critiqued, and new eccentric exercises and interventions were introduced. The following four chapters included experimental research on: first) the effects of running velocity on running kinetics (e.g. vertical and leg stiffness) (i.e. chapter 5); second) relationships between hamstring injuries and leg asymmetries during running (i.e. chapter 6); third) the relationships between training background and optimum length, and fascicle length (i.e. chapter 7); forth) a case study on an eccentric exercise intervention for a previously injured athlete (i.e. chapter 8); and, finally) the effects of eccentric exercise on the optimum angle (knee flex ors and extensors) and injury occurrence in professional soccer players (i.e. chapter 9).
The purpose of chapter 5 was to investigate the effects of running velocity of running kinetics and kinematics in Australian Rules football players. Sixteen semiprofessional Australian football players participated in this study. The subjects performed running bouts at 40%, 60%, 80% and 100% of their maximum velocity on a Woodway non-motorized treadmill. The variables of interest included: vertical force (Fv), relative veriical force (RFv), vertical stiffness, leg stiffness, horizontal force (Fb), relative horizontal force (RFb), contact times, impulse, stride frequency and stride length. As running velocity increased from 40% to 60%, RF v and RF h increased by 14.3% ((Effect Size (ES)= 1.0)) and 34.4% (ES= 4.2) respectively. The changes in RFv and RFh from 60% to 80% were 1.0% (ES= 0.05) and 21.0% (ES= 2.9). And finally, the changes in RFv and RFh from 80% to maximum were 2.0% (ES = 0.1) and 24.3% (ES= 3.4) respectively. The total increase in RFh from the slowest running speed (i.e. 40% max) to maximum was 102.0% (ES= 9.3). Vertical stiffness significantly increased between each increasing running velocity (p < 0.05) while leg stiffness remained constant. Both stride frequency and stride length significantly increased with each increasing velocity (p < 0.05). Conversely contact times, impulse and the vertical displacement of the center of mass significantly decreased with running velocity (p < 0.05). A significant positive correlation was found between Fh and maximum running velocity (r = 0.4 7). For the kinematic variables, only stride length was found to have a significant positive correlation with maximum running velocity (r = 0.66). It would seem that increasing maximal sprint velocity may be more dependent on horizontal force prodnction as apposed to vertical force production.
The purpose of chapter 6 was to quantify the magnitnde of leg asymmetry in kinetic and kinematic variables during running in non-injured and previously injured Australian Rules football (ARF) players. The players included a group of non-injured ARF players (n = II) and a group of previously injured ARF players (n = 11; hamstring injuries only). The players in the injured group had at least one acute hamsh·ing injury in the previous two years. The legs of the non-injured players were classified as dominant and non-dominant whereas the legs of the injured players were classified as injured or non-injured. The players ran on a non-motorized force h·eadmill at approximately 80% of their maximum velocity (Vmax). For the noninjured players, there were no significant differences between dominant and nondominant legs for any of the variables. For the injured players, the only variable that was significantly (p<0.001) different between the injured and non-injured leg was horizontal force production (175 ± 30 vs. 324 ± 44 N). Furthermore, the injured leg (injured group) produced significantly less (30.2% and 33.9%) horizontal force than either legs (dominant and non-dominant legs) of the non-injured group, and the noninjured leg produced significantly more (18.2% and 22.5%) horizontal force than either legs of the non-injured group. In the present study, hamstring injures appeared to have an influence on leg asymmetry in horizontal but not vertical force production during running at sub-maximal velocities.
The purpose of chapter 7 was to investigate differences in optimum angle of peak torque (knee extensors and flexors) and muscle architecture ( vastus lateralis) between nine cyclists and nine Australian Rules Football (ARF) players. The angles of peak torque of the ARF players were significantly (p<0.05) greater during knee extension 70.8 ± 3.5° vs. 66.6 ± 5.9° and smaller during knee flexion 26.2 ± 2.9° vs. 32.3 ± 3.8° compared with the cyclists. The ARF players had significantly (P<0.05) smaller pennation angles 19.3 ± 2.0° vs. 24.9 ± 2.5° and longer fascicle lengths 7.9 ± 0.7 cm vs. 6.2 ± 0.8 cm in comparison with the cyclists. There were no significant differences between groups in regards to muscle thickness or peak torque ratios between the quadriceps and hamstrings (Q/H ratio). Muscle architectural changes associated with resistance strength training need to be investigated so as the effects of training on architecture and functional perfonnance can be detennined.
The purpose of chapter 8 was to present an eccentric exercise intervention, including multi-joint and closed chain exercises, for an Australian Football player with a history of acute hamstring injuries. The athlete was a 24 year old Australian Rules football player with a medical history of three hamstring muscle strain injuries to his right hamstring in the previous four years. After the first three phases of the intervention (i.e. nine weeks), the optimum angle of peak torque during knee flexion decreased from 37.3 to 23.9° in the injured leg, and from 24.3 to 20.3° in the healthy leg. After the first nine weeks, the optimum angles remained constant for another 23 weeks. The optimum angle of peak torque was also shifted in the knee extensors by 3.9° (injured leg) and 3.4° (healthy leg) after nine weeks and remained constant for the remaining 23 weeks. Quadriceps to hamstring peak torque ratio's (Q/H ratios) and peak torque during knee flexion and extension remained constant throughout the intervention. An intervention consisting of multi-joint and closed-chain eccentric exercises can be safe and effective for altering the optimum angle of peak torque (i.e. shifting to longer muscle lengths), after acute hamstring injuries.
The purpose of chapter 9 was to investigate the effects of eccentric exercise on injury occurrence (i.e. hamstrings and rectus femoris) and optimum angle of peak torque (i.e. knee flexors and extensors) in professional soccer players. Twenty three members of a Spanish Professional League soccer team (Division II) were randomly assigned to either an eccentric exercise intervention group (EG) or a control group (CG). Both groups performed regular soccer training during the four week study, which was conducted during the clubs pre-season. After the four weeks, the optimum angles of the knee flexors were significantly (p < 0.05) decreased (i.e. increase in optimum length) by 2.0° in the CG and by 4.0° in the EG. The change in the EG was significantly different to the CG. The optimum angles of the knee extensors were significantly increased (i.e. increase in optimum length) in the EG only by 6.7°. Peak torque levels and ratios of quadriceps to hamstring (Q/H ratios) were not significantly altered throughout the study for either group. There were no injuries reported in the EG, but two rectus femoris muscle strain injuries reported in the CG. It appears that eccentric exercise can shift the optimum length of the knee flexors and extensors and these shifts may have a positive influence in reducing the incidence of injury.
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Rohadhia, Wafina. "Cardio-metabolic and neuromuscular adaptations following whole-body eccentric resistance training in older adults." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2019. https://ro.ecu.edu.au/theses/2203.
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Regular exercise is key to minimise the negative effects of aging on health; however, it is reported that 65% of older Australians are categorised as physically inactive. Recent studies reported that eccentric resistance training (ECC-RT) is an effective modality to produce cardio-metabolic and neuromuscular benefits for older adults. The present study tested the hypothesis that ECC-RT of several major muscle groups would produce positive changes in cardio-metabolic and neuromuscular parameters in older adults with metabolic syndrome.
Six men and 11 women aged between 60 and 80 (70.0 ± 5.0) years old with dyslipidaemia and BMI >25 kg/m2 participated in this study. It is important to note that no control group nor control period applied before the participants commenced their training. All participants performed a whole-body ECC-RT program consisting of eight exercises (i.e. chest press, lateral pulldown, leg extension, leg curl, biceps curl, triceps extension, calf raises and abdominal crunch). The training sessions were performed twice a week for 8-weeks (16 sessions in total), with progressively increasing intensity from 10-100% of the individual’s one repetition maximum (1RM) for each exercise. Physical function (400-m walk, 30-s repeated chair rise, timed up-and-go), 1RM strength for all exercises, blood lipid profiles (total cholesterol, LDL, HDL, triglyceride), and glycaemic control parameters (fasting glucose, insulin, fructosamine, HOMA-IR index) were measured at baseline, mid-point (after 8 training sessions), and post-training (1-2 days after the last training session). Sensory organisation (SOT), body composition and isometric (MVIC) and isokinetic concentric (MVCC) maximal voluntary contraction (MVC) strength of the knee and elbow extensors and flexors were measured at baseline and post-training.
1RM strength increased significantly (p<0.05) for all exercises with 34–115% improvements from baseline. Physical function variables such as 400-m walk (12 ± 7%), 30-s repeated chair rise (18 ± 15%), timed up-and-go (13 ± 6%), and sensory organisation test (6 ± 8%) also showed significant improvements from baseline to post-training. However, no significant increases in isometric and isokinetic concentric MVC strength of the knee and elbow extensors and flexors were found. Although some participants showed some changes in body composition variables, no significant changes in percentage of body fat, fat mass and lean body mass were evident as a group. Total cholesterol (TC) (-5 ± 11%) and LDL-cholesterol (-8 ± 13%) decreased significantly after 4-weeks of training, and HDL-cholesterol showed a significant increase after 8-weeks (4 ± 9%), but the magnitude of changes in these variables were not large. Triglyceride (TG), fasting glucose, insulin, HOMA-IR and fructosamine did not show any significant changes over time. These results did not necessarily support the hypothesis, but were in agreement with previous studies that showed improvements in muscle strength and physical functions following ECC-RT. Interestingly, the magnitude of the changes in 1RM strength (leg extension, leg curl, triceps extension, biceps curl) did not necessarily correlate with those of MVIC and MVCC assessed by the isokinetic dynamometer for the same muscle groups (i.e. the increases in 1RM strength were much greater than that of MVIC and MVCC). Although the TC, LDL and HDL-cholesterol showed some improvements, the magnitude of the changes was not large. TG and other glycaemic control parameters did not show significant changes, although previous studies reported greater changes after ECC-RT of the knee extensors or descending stair walking training. It is interesting that the amount of muscles trained in the present study appear to be much greater than that of previous studies, but the training effects found in the present study were less. It may be that 16 sessions of whole-body ECC-RT over 8-weeks were not enough to induce large changes in some of the parameters. Thus, future studies need to examine whether ECC-RT with varying frequency, volume, intensity and duration could produce more positive changes in body composition and blood markers in older adults.
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Jönhagen, Sven. "Muscle injury and pain : effects of eccentric exercise, sprint running, forward lunge and sports massage /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-182-2/.
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Yu, Ji-Guo, Jing-Xia Liu, Lena Carlsson, Lars-Eric Thornell, and Per S. Stål. "Re-evaluation of sarcolemma injury and muscle swelling in human skeletal muscles after eccentric exercise." Umeå universitet, Idrottsmedicin, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-68821.
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The results regarding the effects of unaccustomed eccentric exercise on muscle tissue are often conflicting and the aetiology of delayed onset muscle soreness (DOMS) induced by eccentric exercise is still unclear. This study aimed to re-evaluate the paradigm of muscular alterations with regard to muscle sarcolemma integrity and fibre swelling in human muscles after voluntary eccentric exercise leading to DOMS. Ten young males performed eccentric exercise by downstairs running. Biopsies from the soleus muscle were obtained from 6 non-exercising controls, 4 exercised subjects within 1 hour and 6 exercised subjects at 2-3 days and 7-8 days after the exercise. Muscle fibre sarcolemma integrity, infiltration of inflammatory cells and changes in fibre size and fibre phenotype composition as well as capillary supply were examined with specific antibodies using enzyme histochemistry and immunohistochemistry. Although all exercised subjects experienced DOMS which peaked between 1.5 to 2.5 days post exercise, no significant sarcolemma injury or inflammation was detected in any post exercise group. The results do not support the prevailing hypothesis that eccentric exercise causes an initial sarcolemma injury which leads to subsequent inflammation after eccentric exercise. The fibre size was 24% larger at 7-8 days than at 2-3 days post exercise (p<0.05). In contrast, the value of capillary number per fibre area tended to decrease from 2-3 days to 7-8 days post exercise (lower in 5 of the 6 subjects at 7-8 days than at 2-3 days; p<0.05). Thus, the increased fibre size at 7-8 days post exercise was interpreted to reflect fibre swelling. Because the fibre swelling did not appear at the time that DOMS peaked (between 1.5 to 2.5 days post exercise), we concluded that fibre swelling in the soleus muscle is not directly associated with the symptom of DOMS.
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Stacy, Mitchel R. "The Effect of Eccentric Exercise-Induced Muscle Injury on Vascular Function and Muscle Blood Flow." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1302229144.
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Crawford, Scott K. "Changes in Muscle Mechanical Properties Due to Total Loading Associated with Massage Following Eccentric Exercise." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1448309216.
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Banyard, Henry. "Effects of pulsed electromagnetic field therapy on symptoms associated with eccentric exercise-induced muscle damage." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/705.
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Unaccustomed exercise consisting of eccentric contractions induces muscle damage that is characterised by muscle weakness, soreness, swelling and increased muscle stiffness. These symptoms affect daily activities and athletic performance; therefore, interventions to attenuate the symptoms and enhance recovery from muscle damage are necessary. Pulsed electromagnetic field therapy (PEMFT) is anecdotally reported to increase muscle blood flow and oxygenation to enhance tissue healing. One previous study showed that PEMFT was effective for alleviating muscle soreness and losses in range of motion after exercise. However, studies investigating the effect of PEMFT on recovery of muscle strength following eccentric exercise are lacking. The purposes of this study were to investigate the effects of PEMFT treatment on muscle temperature, blood flow and oxygenation (Study 1), and on the symptoms associated with eccentric exerciseinduced muscle damage (Study 2).
In Study 1, the effects of 30 min PEMFT on muscle temperature, blood flow and oxygenation were examined using nine healthy men (23.6 ± 3.7 years). A device called e-cell™was used for PEMFT in this study, which is the size and shape of a computer mouse weighing approximately 140 g, and sham treatment used a visually identical device without pulsed electromagnetic field production. PEMFT was applied over the bicep brachii of one arm for 30 min, and the other arm received sham treatment, while each subject was lying supine on a massage table. The device was marked A or B; thus, both the investigator and subjects were blinded as to which device was active e-cell™ or sham, and the use of dominant or non-dominant arm for device A or B was randomised and counterbalanced among subjects. Pre-treatment muscle temperature was measured by a thermistor needle (22 gauge, 70 mm) inserted to a depth of 20 mm at 10 mm laterally adjacent to a near infrared spectroscopy (NIRS) probe unit that was attached to the skin at the mid-belly of the biceps brachii, and the post-treatment measurement was taken at 5 mm proximal to the first site. The NIRS was used to measure tissue oxygenation index (TOI), a measure of muscle oxygenation, and total haemoglobin content (tHb), an indirect measure of blood flow, which were recorded throughout the treatment period. Changes in muscle temperature from before to immediately posttreatment were compared between e-cell™ and sham conditions using a paired t-test, and changes in TOI and tHb from baseline to 30 min of treatment (0, 10, 20 and 30 min) were compared between conditions by a two-way repeated measures analysis of variance (ANOVA). Muscle temperature significantly (p
In Study 2, eight men and eight women (24.8 ± 6.2 years) performed two bouts of 60 maximal isokinetic (30°⋅s-1) eccentric contractions of the elbow flexors on each arm separated by 4 weeks. In each eccentric contraction, the elbow joint was forcibly extended from a flexed (90°) to a fully extended position (0°). At immediately after, and 1-4 days following the exercise, the exercised arm received 30 min of either e-cell™ or sham treatment described above. The arm dominance and the order of treatment conditions were randomised and counterbalanced among the subjects, and the study was conducted in a double-blinded manner. Dependant variables included maximal voluntary contraction (MVC) strength, range of motion (ROM), upper arm circumference (CIR), muscle soreness by a visual analogue scale, muscle tenderness measured by pressure pain threshold (PPT) and plasma CK activity. Changes in these variables for 7 days following the exercise were compared between e-cell™ and sham treatment conditions, men and women, and the first and second bouts of exercise by a two-way repeated measures ANOVA. The changes in the variables from pre- to post-treatment were also analysed by a two-way repeated measures ANOVA. All variables changed significantly (p
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Grigg, Nicole Lorraine. "The acute adaptations of normal and pathological human Achilles tendons to eccentric and concentric exercise." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/47048/1/Nicole_Grigg_Thesis.pdf.
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Eccentric exercise is the conservative treatment of choice for mid-portion Achilles tendinopathy. While there is a growing body of evidence supporting the medium to long term efficacy of eccentric exercise in Achilles tendinopathy treatment, very few studies have investigated the short term response of the tendon to eccentric exercise. Moreover, the mechanisms through which tendinopathy symptom resolution occurs remain to be established. The primary purpose of this thesis was to investigate the acute adaptations of the Achilles tendon to, and the biomechanical characteristics of, the eccentric exercise protocol used for Achilles tendinopathy rehabilitation and a concentric equivalent. The research was conducted with an orientation towards exploring potential mechanisms through which eccentric exercise may bring about a resolution of tendinopathy symptoms. Specifically, the morphology of tendinopathic and normal Achilles tendons was monitored using high resolution sonography prior to and following eccentric and concentric exercise, to facilitate comparison between the treatment of choice and a similar alternative. To date, the only proposed mechanism through which eccentric exercise is thought to result in symptom resolution is the increased variability in motor output force observed during eccentric exercise. This thesis expanded upon prior work by investigating the variability in motor output force recorded during eccentric and concentric exercises, when performed at two different knee joint angles, by limbs with and without symptomatic tendinopathy. The methodological phase of the research focused on establishing the reliability of measures of tendon thickness, tendon echogenicity, electromyography (EMG) of the Triceps Surae and the standard deviation (SD) and power spectral density (PSD) of the vertical ground reaction force (VGRF). These analyses facilitated comparison between the error in the measurements and experimental differences identified as statistically significant, so that the importance and meaning of the experimental differences could be established. One potential limitation of monitoring the morphological response of the Achilles tendon to exercise loading is that the Achilles tendon is continually exposed to additional loading as participants complete the walking required to carry out their necessary daily tasks. The specific purpose of the last experiment in the methodological phase was to evaluate the effect of incidental walking activity on Achilles tendon morphology. The results of this study indicated that walking activity could decrease Achilles tendon thickness (negative diametral strain) and that the decrease in thickness was dependent on both the amount of walking completed and the proximity of walking activity to the sonographic examination. Thus, incidental walking activity was identified as a potentially confounding factor for future experiments which endeavoured to monitor changes in tendon thickness with exercise loading. In the experimental phase of this thesis the thickness of Achilles tendons was monitored prior to and following isolated eccentric and concentric exercise. The initial pilot study demonstrated that eccentric exercise resulted in a greater acute decrease in Achilles tendon thickness (greater diametral strain) compared to an equivalent concentric exercise, in participants with no history of Achilles tendon pain. This experiment was then expanded to incorporate participants with unilateral Achilles tendinopathy. The major finding of this experiment was that the acute decrease in Achilles tendon thickness observed following eccentric exercise was modified by the presence of tendinopathy, with a smaller decrease (less diametral strain) noted for tendinopathic compared to healthy control tendon. Based on in vitro evidence a decrease in tendon thickness is believed to reflect extrusion of fluid from the tendon with loading. This process would appear to be limited by the presence of pathology and is hypothesised to be a result of the changes in tendon structure associated with tendinopathy. Load induced fluid movement may be important to the maintenance of tendon homeostasis and structure as it has the potential to enhance molecular movement and stimulate tendon remodelling. On this basis eccentric exercise may be more beneficial to the tendon than concentric exercise. Finally, EMG and motor output force variability (SD and PSD of VGRF) were investigated while participants with and without tendinopathy performed the eccentric and concentric exercises. Although between condition differences were identified as statistically significant for a number of force variability parameters, the differences were not greater than the limits of agreement for repeated measures. Consequently the meaning and importance of these findings were questioned. Interestingly, the EMG amplitude of all three Triceps Surae muscles did not vary with knee joint angle during the performance of eccentric exercise. This raises questions pertaining to the functional importance of performing the eccentric exercise protocol at each of the two knee joint angles as it is currently prescribed. EMG amplitude was significantly greater during concentric compared to eccentric muscle actions. Differences in the muscle activation patterns may result in different stress distributions within the tendon and be related to the different diametral strain responses observed for eccentric and concentric muscle actions.
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Raue, Ulrika. "Effects of concentric vs eccentric resistance training on skeletal muscle adaptations in humans." Virtual Press, 2001. http://liblink.bsu.edu/uhtbin/catkey/1221284.
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The Beothuk Indians were an extinct group of Amerinds who were among the earliest founders of Newfoundland. In literature, the Beothuk were described as perhaps being phenotypically more similar to Europeans than Asians (Gatschet 1890, Lloyd 1875, 1876a, Marshall 1996). In this research, mitochondrial DNA (mtDNA) analysis was performed on a Beothuk individual in order to determine his haplotype and, perhaps, shed light on the origins of the Beothuk.For this analysis, a tooth of Nonosabasut, a Beothuk chief who died in 1819 was loaned from the Royal Museum of Scotland. Ancient DNA was extracted from 172 mg of dentin from the tooth. The DNA was cut with two blunt-end restriction enzymes, RsaI and HaeIII. Double-stranded DNA adapters were ligated to the blunt ends. A single adapter was used to amplify the resulting fragments using PCR. In this manner, two libraries of the DNA were created that could be readily reamplified using a small amount of the PCR product. mtDNA type was determined by amplifying specific regions and performing Restriction Fragment Length Polymorphism analysis and sequencing. It was determined that the Beothuk individual had a 9-bp deletion at nucleotide position (np) 8272, an Alul restriction site at np 5176, and heteroplasmy for a HincII restriction site at np 13,259, indicating that the Beothuk individual falls into the Native American Haplogroup B. Haplogroup B is not present in modern Siberian populations, whereas the remaining Native American mtDNA haplogroups are. It has been hypothesized that Haplogroup B arrived in the Americas at a different time than haplogroups A, C, D, and X, about 16,000-13,000 YBP (Years Before Present) (Starikovskaya et al. 1998). Haplogroup B can be found in some modern Taiwanese, Japanese, Korean, Evenk, and other Asian populations.Sequencing of the D-Loop region revealed a G to A transition at np 16303. To our knowledge, this transition was never previously reported in a Native American. This transition has been reported in Tibetans, Koreans, Hans, and Japanese, all considered to be southeast Asian Causacoids (Torroni et al. 1993b, 1994b). This transition, also frequently described in the Caucasian Haplogroup H, is especially prevalent in Spain and among the Basque. It is described as a root haplotype of Haplogroup H whose expansion was estimated to be between 12,300-13,200 YBP (Torroni et al. 1998). This time estimate coincides with the expansion of Haplogroup B. One possible explanation for this transition may be some admixture of the Beothuk with a Caucasian population.School of Physical Education
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Jonsson, Per. "Eccentric training in the treatment of tendinopathy." Doctoral thesis, Umeå : Sports Medicine, Umeå university, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-25856.
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Tough, Murray William. "Low-intensity laser light and the recovery from exhaustive eccentric exercise in human elbow flexor muscles." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ52956.pdf.
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Kasper, Christine. "Inflammatory response to a high-force eccentric exercise protocol in oral contraceptive users and non-users." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/kasper/KasperC0508.pdf.
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Conradie, Johannes David. "Investigation of myostatin and relevant regulators during muscle regeneration after an acute bout of eccentric exercise." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95947.
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Thesis (MSc)--Stellenbosch University, 2014.ENGLISH ABSTRACT: The aim of this study was to investigate the powerful muscle regulator, myostatin, and its regulators in response to an acute bout of plyometric training. The participants were recruited and screened by characterization by means of isometric force production tests, baseline blood creatine kinase levels and VO2 max results. The selected individuals (n=15) were subjected to a baseline muscle biopsy for comparative purposes. The study made use of plyometric jumping, as source of eccentric exercise, to serve as an exercise intervention after which muscle biopsies (4 hours post and 24 hours post) and blood draw (4 hours post, 24 hours post and 48 hours post) samples were taken. Maximal voluntary isometric contractions of the knee extensors were also measured immediately after the exercise protocol and after 1 week recovery. Creatine kinase (CK) analysis on the serum samples was used to conclude muscle damage. The muscle biopsy samples were used for protein quantification (Western blot) and gene expression assessment (semi-quantitative and real-time PCR). The results showed decreased force production immediately after eccentric exercise (p < 0.05), while returning back to baseline values at 1 week post exercise and CK results showed a significant increases at 4 hours (p<0.05), 24 hours (p<0.001) and 48 hours (p<0.01) after exercise. There were no significant differences in myostatin precursor protein (43 kDa), phosphorylated Smad2,3, Smad7 or activin receptor IIb in response to eccentric exercise. However, the follistatin protein was increased at both 4 hours and 24 hours after exercise (p<0.01). RNA analysis of the extracellular matrix (ECM) protein, decorin, revealed the existence of the splice variants A1 and A2 in human skeletal muscle. The RT-PCR analysis (n=4) of these variants showed no significant difference when comparing pre- to post-exercise. The decorin core protein was also investigated by means of antibody probing and results revealed the need for ABC chondroitinase enzyme treatment before immunoblotting of human skeletal muscle samples. The results concerning knee extensor force reduction and circulating creatine kinase showed the effectiveness of plyometric jumping in producing skeletal muscle damage in the lower limbs of unfit individuals, unaccustomed to eccentric exercise. In conclusion, myostatin, and its associated signalling cascade, are not activated in early muscle regeneration, but follistatin is increased during this phase possibly aiding and initiating the muscle repair process. Future studies: Variants of decorin are expressed in human skeletal muscle, increasing the complexity that should be taken into account in studies concerning the regulation of decorin in a human model. Investigation into myostatin protein at different post-translational levels needs more clarification. Published methods and materials used in different laboratories are not consistent and investigators should attempt to standardise protocols in order to compare results between studies more effectively. Of importance, these results show that the myostatin at protein level report different results compared to mRNA analysis and that more investigation into myostatin regulatory factors, with special reference to follistatin and decorin, is needed in future human models.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die kragtige spiere reguleerder, miostatin, en sy reguleerders in reaksie op 'n akute aanval van pliometriese spronge te ondersoek. Die deelnemers is gewerf en gekeur deur karakterisering deur middel van isometriese krag produksie toetse, basislyn bloed kreatien kinase vlakke en VO2maks resultate. Die geselekteerde individue (N = 15) is onderhewig aan 'n basislyn spierbiopsie vir vergelykende doeleindes. Die studie het gebruik gemaak van pliometriese spronge (essentriese spier aksie) as die oefening intervensie waarna spierbiopsie (4 uur na en 24 uur na) en bloed (4 uur na, 24 uur na en 48 uur na) monsters geneem is. Isometriese kontraksies van die knieverlengers is ook gemeet onmiddellik na die oefening protokol en na 1 week se herstel. Kreatine kinase (KK) ontleding van die serum monsters is gebruik om spierskade aftelei. Die spierbiopsie monsters was gebruik vir proteïen kwantifisering (Western klad) en die assessering van geen uitdrukking (semi-kwantitatiewe en real-time PCR). Die resultate het gewys dat krag produksie afgeneem het onmiddellik na essentriese oefening (p <0.05), terwyl dit terugkeer na die oorspronklike waardes 1 week na oefening en KK resultate toon 'n beduidende toename by 4 uur (p <0,05), 24 uur (p <0,001) en 48 uur (p <0,01) na oefening. Daar was geen betekenisvolle verskille in Miostatien voorloper proteïen (43 kDa), gefosforileerde Smad2,3, Smad7 of Activin reseptoor IIb in reaksie op essentriese oefening. Dit is egter die follistatien proteïen wat verhoog by beide 4 uur en 24 uur na oefening (p <0,01). RNS ontleding van die ekstrasellulêre matriks (ESM) proteïen, decorin, het die bestaan van die splitsing variante A1 en A2 in menslike skeletspier, aan die lig gebring. Die RT-PCR analise (n = 4) van hierdie variante het geen betekenisvolle verskille getoon wanneer voor met na-oefening vergelyk is. Die decorin kern proteïen is ook ondersoek deur middel van teenliggaam afhanklike metodes en resultate het die behoefte aan ABC chondroitinase ensiem behandeling voor immunokladding van menslike skeletspier monsters gesteun. Die resultate aangaande knieverlenger krag vermindering en sirkuleerende kreatien kinase het die doeltreffendheid van pliometriese spronge in die vervaardiging van skeletspier skade in die onderste ledemate van individue ongewoond aan essentriese oefening verseker. Ten slotte, Miostatien, en sy verwante sein kaskade, is nie geaktiveer vroeg in spier herstelling, maar follistatien is tydens hierdie fase verhoog en help moontlik met die aanvang van die spier herstel. Toekomstige studies: variante van decorin word uitgedruk in menslike skeletspier, wat die kompleksiteit aangaande decorin verhoog en dit is iets wat in ag geneem moet word in studies wat handel oor die regulering van decorin in mens modelle. Ondersoek na miostatien proteïen op verskillende na-translasie vlakke moet meer duidelikheid verkry. Gepubliseer metodes en materiaal wat gebruik word in verskillende laboratoriums is nie konsekwent en ondersoekbeamptes moet probeer om protokolle te standaardiseer sodat resultate van studies meer effektief kan vergelyk word. Van belang is, die resultate wys dat miostatien op proteïen vlak verskillende resultate vertoon in vergelyking met boodskapper-RNS ontleding en dat meer ondersoek na miostatien regulerende faktore, met spesiale verwysing na follistatien en decorin, nodig is in toekomstige menslike modelle.
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Close, Graeme L. "The effects of eccentric exercise on delayed onset muscle soreness, muscle function and free radical production." Thesis, Liverpool John Moores University, 2004. http://researchonline.ljmu.ac.uk/5626/.
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Delayed onset muscle soreness (DOMS) is a muscle strain injury that presents as tender or aching muscles, often felt during palpation or movement. DOMS is associated with unaccustomed, high-force muscular work and is most pronounced if the work involves a significant eccentric component. Despite substantial research into DOMS its aetiology is still unresolved. There have been recent suggestions that reactive oxygen species (ROS) may be involved in the aetiology of DOMS, however the evidence for this association is equivocal. Therefore, the aims of this thesis were to investigate the effects of unaccustomed exercise (downhill running) on DOMS, specifically investigating the role of ROS in its aetiology. Once this had been established, the effects of dietary intervention and antioxidant supplementation on DOMS and ROS were also investigated. Study 1 demonstrated that downhill running, which resulted in DOMS, also induced the production of ROS, detected by ESR spectroscopy as well as an increases in serum malondialdehyde (MDA) concentration. It was noted that this increase in ROS occurred -72 h post exercise and was therefore likely to be a result of increased phagocyte activity. Furthermore, the increase in ROS occurred after peak DOMS and when muscle function (as determined by losses of muscle torque assessed by isokinetic dynamometry) was returning to pre-exercise levels, suggesting a temporal dissociation between ROS production and DOMS following downhill running. Circulating levels of ROS were still increasing 72 h post exercise so this study was unable to map the full time-course of ROS production following downhill running. Study 2 investigated the effects of dietary CHO intake on DOMS, ROS and muscle function. It was found that pre-exercise CHO status had no effect on ROS production, DOMS or losses of muscle function following downhill running. The study demonstrated a bi-phasic increase in creatine kinase (CK), with the second increase corresponding with the post-exercise ROS production. The study extended the postexercise sampling period to 96 h, however, ROS were still increasing at this time and therefore this study was also unable to conclude a definitive tune course of ROS production following downhill running. Study 3 demonstrated that prolonged ascorbic acid supplementation attenuated the post-exercise increase in ROS production compared to placebo. This attenuation in ROS prevented the secondary peak in CK activity, however it had no effect on DOMS. Interestingly, supplementation with ascorbic acid resulted in more prolonged losses of muscle function. ROS peaked at 96 h post exercise and therefore the time course ofROS production following downhill running was established. From these studies it was concluded that downhill running did result in post-exercise ROS production. This post-exercise ROS production was associated with secondary muscle damage as measured by plasma CK activity although it had no effect on DOMS. Since supplementation with ascorbic acid attenuated ROS production and prolonged the losses of muscle function, it was suggested that ROS produced by phagocytes m the days following muscle-damaging exercise have a positive role in assisting in the recovery from the trauma.
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Wojcik, Janet Regina. "Effect of Carbohydrate-Protein Beverage on Glycogen Resynthesis and Muscle Damage Induced By Eccentric Resistance Exercise." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30443.
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This study examined effects of carbohydrate (C), carbohydrate-protein (CP), or placebo (P) beverages following eccentric resistance exercise on muscle damage by serum creatine kinase (CK), muscle protein breakdown by urinary 3-methylhistidine (3MH), muscle soreness, isokinetic muscle strength, muscle glycogen resynthesis, and serum hormones. Untrained males (N=26) underwent a 9-day controlled meat-free diet and 24 hr urine collections. To reduce glycogen, subjects cycled for 40 min at 70% of VO2peak followed by 5 cycling sprints on day 4 evening. On day 5, fasted subjects performed 100 eccentric leg flexions at 120% of 1-RM and drank C (n=8, 1.25 g C/kg), CP (n=9, 0.875 g C/kg, 0.375 g protein/kg), or P (n=9) beverages immediate post-exercise (IPE) and 2 hr later. Muscle biopsies were taken IPE on day 5, and days 6 and 8 mornings. Blood was obtained days 4-10 fasted plus IPE, 3 hr, and 6 hr post-exercise on day 5. At 3 hr on day 5, insulin was higher for CP (24.6 ( 15.5 µIU/ml) and C (17.2 +/- 10.9 µIU/ml) than P (5.3 +/- 0.4 µIU/ml, p<.05). Glycogen was low on day 5, partially recovered on day 6, and normal by day 8 (p<.01) with no difference among groups. Isokinetic quadriceps peak torque at 60o/s decreased 24% on day 6 and remained depressed by 21% on d 8 (p<.01) for all groups. Soreness peaked on day 7 and CK on day 8 (p<.01) with no differences by group. CK increased (p<.01) over day 5 (delta CP 24.6 +/- 19.1, delta P 39.2 +/- 71.6, delta C 70.8 +/- 60.4 U/L) and was highest for C (p<.05). On day 5, CP had lowest 3MH (193.0 +/- 13.8 µmol/d) versus C (251.1 +/- 22.5 µmol/d, p<.05). Testosterone at 3 hr on day 5 was lower for C (4.2 +/- 0.3 ng/ml) and CP (4.3 +/- 0.3 ng/ml) versus P (5.1 +/- 0.2 ng/ml, p<.05). In summary, glycogen, muscle strength and soreness were unaffected by beverage. However, a CP beverage may be beneficial for reducing muscle damage and protein breakdown on the day of eccentric resistance exercise.Ph. D.