Depth-dependent variations in Achilles tendon deformations with age are associated with reduced plantarflexor performance during walking

Franz, Jason R.; Thelen, Darryl G.

doi:10.1152/japplphysiol.00114.2015

Cited by 50 publications

(48 citation statements)

References 37 publications

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“…The influence of this design on muscle fascicle and tendon energetics remains an area of future research. We note here, however, that recent in vivo studies on non-uniform Achilles tendon deformation have observed that tendon fascicles arising from the SO and gastrocnemius may function as independent structures during walking [67,68].…”

mentioning

confidence: 52%

Human ankle plantar flexor muscle–tendon mechanics and energetics during maximum acceleration sprinting

Lai

Schache

Brown

et al. 2016

J. R. Soc. Interface.

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Tendon elastic strain energy is the dominant contributor to muscle-tendon work during steady-state running. Does this behaviour also occur for sprint accelerations? We used experimental data and computational modelling to quantify muscle fascicle work and tendon elastic strain energy for the human ankle plantar flexors (specifically soleus and medial gastrocnemius) for multiple foot contacts of a maximal sprint as well as for running at a steady-state speed. Positive work done by the soleus and medial gastrocnemius muscle fascicles decreased incrementally throughout the maximal sprint and both muscles performed more work for the first foot contact of the maximal sprint (FC1) compared with steady-state running at 5 m s 21 (SS5). However, the differences in tendon strain energy for both muscles were negligible throughout the maximal sprint and when comparing FC1 to SS5. Consequently, the contribution of muscle fascicle work to stored tendon elastic strain energy was greater for FC1 compared with subsequent foot contacts of the maximal sprint and compared with SS5. We conclude that tendon elastic strain energy in the ankle plantar flexors is just as vital at the start of a maximal sprint as it is at the end, and as it is for running at a constant speed.

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mentioning

confidence: 52%

Human ankle plantar flexor muscle–tendon mechanics and energetics during maximum acceleration sprinting

Lai

Schache

Brown

et al. 2016

J. R. Soc. Interface.

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“…Muscle-tendon unit (MTU) lengths for both MG and soleus were calculated from the joint kinematics using regression equations defined by Hawkins & Hull (16). Tendinous tissue (TT, including both proximal and distal free tendon and aponeurosis) lengths for both MG and soleus were calculated as L TT = L MTU -L FAS* cos(pennation angle), where L MTU is MTU length and L FAS is muscle fascicle length (15). MTU and TT lengths were normalized by dividing them by their corresponding reference lengths, which were determined in the same way as the muscle fascicle reference lengths.…”

Section: Muscle-tendon Unit and Tendon Lengthmentioning

confidence: 99%

“…In fact, we showed earlier that 6-minute walking test results positively correlate with Achilles tendon stiffness in older adults (39). Additionally, recent studies using ultrasound imaging and musculoskeletal modeling have started to unfold more complex interactions between Achilles tendon mechanical properties and triceps surae muscle function in which age-related Achilles tendon interfascicular adhesions coupling gastrocnemius and soleus muscle function may contribute to the reduced plantarflexor performance in walking in older adults (15,16).…”

Section: Introductionmentioning

confidence: 99%

Slower Walking Speed in Older Men Improves Triceps Surae Force Generation Ability

Stenroth

Sipilä

Finni

et al. 2017

Medicine &Amp; Science in Sports &Amp; Exercise

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Purpose: Older adults walk slower than young adults but it is not known why. Previous research suggests that ankle plantarflexors may have a crucial role in the reduction of walking speed. The purpose of this study was to investigate age-related differences in triceps surae muscle-tendon function during walking to further investigate the role of plantarflexors in the age-related reduction of walking speed. Methods: Medial gastrocnemius and soleus muscle fascicle lengths were measured using ultrasound imaging during walking from 13 young (25±4yrs) men at preferred walking speed, and from 13 older (73±5yrs) men at preferred speed and at the young men's preferred speed. Muscle-tendon unit lengths were calculated from joint kinematics and tendinous tissue lengths were calculated by subtracting muscle lengths from muscle-tendon unit lengths. In addition, ground reaction forces and electromyographic activity of medial gastrocnemius and soleus were measured. Results: In both medial gastrocnemius and soleus it was observed that at preferred walking speed, older men used a narrower muscle fascicle operating range and lower shortening velocity at the estimated time of triceps surae peak force generation compared to young men. Fascicles also accounted for a lower proportion of muscle-tendon unit length changes during the stance phase in older compared to young men. Significant differences in triceps surae muscle function were not observed between age groups when compared at matched walking speed. Conclusions: In older men, walking at preferred speed allows triceps surae muscles to generate force with more favorable shortening velocity and to enhance use of tendinous tissue elasticity compared to walking at young men's preferred speed. The results suggest that older men may prefer slower walking speeds to compensate for decreased plantarflexor strength.

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“…To overcome this limitation, we have adopted a novel 2D ultrasound speckle-tracking algorithm to directly image localized Achilles tendon tissue motion in vivo . We have previously elaborated on the technical details of the approach, its validity, and its use during functional and dynamic activities (Chernak et al 2012, Slane et al 2014, Franz et al 2015). In our ongoing experimental work, we use this technique to characterize differences in tendon tissue deformations (i.e., displacements and elongations) during walking between regions of the Achilles free tendon thought to arise from the gastrocnemius and soleus muscles (Franz et al 2015) and how this in vivo behavior changes with aging (Franz et al 2015).…”

Section: Characterizing In Vivo Achilles Tendon Tissue Deformationsmentioning

confidence: 99%

“…Our recent contributions to these efforts have focused on the in vivo characterization of localized AT deformations during walking and the relevance of those deformations to degradations in triceps surae mechanical performance due to aging (Franz et al 2015, Franz et al 2015). Compared to younger tendons, older tendons are thought to exhibit a reduced capacity for inter-fascicle sliding potentially arising from a proliferation of collagen cross-linking and inter-fascicle adhesions (Thorpe et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Imaging and simulation of Achilles tendon dynamics: Implications for walking performance in the elderly

Franz

Thelen

2016

Journal of Biomechanics

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The Achilles tendon (AT) is a complex structure, consisting of distinct fascicle bundles arising from each triceps surae muscle that may act as mechanically independent structures. Advances in tissue imaging are rapidly accelerating our understanding of the complexities of functional Achilles tendon behavior, with potentially important implications for musculoskeletal injury and performance. In this overview of our recent contributions to these efforts, we present the results of complementary experimental and computational approaches to investigate AT behavior during walking and its potential relevance to reduced triceps surae mechanical performance due to aging. Our experimental evidence reveals that older tendons exhibit smaller differences in tissue deformations than young adults between regions of the AT presumed to arise from the gastrocnemius and soleus muscles. These observations are consistent with a reduced capacity for inter-fascicle sliding within the AT, which could have implications for the mechanical independence of the triceps surae muscles. More uniform AT deformations are also correlated with hallmark biomechanical features of elderly gait – namely, a loss of net ankle moment, power, and positive work during push-off. Simulating age-related reductions in the capacity for inter-fascicle sliding in the AT during walking predicts detriments in gastrocnemius muscle-tendon mechanical performance coupled with underlying shifts in fascicle kinematics during push-off. AT compliance, also suspected to vary due to age, systematically modulates those effects. By integrating in vivo imaging with computational modeling, we have gained theoretical insight into multi-scale biomechanical changes due to aging, hypotheses regarding their functional effects, and opportunities for experiments that validate or invalidate these assertions.

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Depth-dependent variations in Achilles tendon deformations with age are associated with reduced plantarflexor performance during walking

Cited by 50 publications

References 37 publications

Human ankle plantar flexor muscle–tendon mechanics and energetics during maximum acceleration sprinting

Human ankle plantar flexor muscle–tendon mechanics and energetics during maximum acceleration sprinting

Slower Walking Speed in Older Men Improves Triceps Surae Force Generation Ability

Imaging and simulation of Achilles tendon dynamics: Implications for walking performance in the elderly

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