Aging effects on the Achilles tendon moment arm during walking

Rasske, Kristen; Franz, Jason R.

doi:10.1016/j.jbiomech.2018.06.001

Cited by 23 publications

(15 citation statements)

References 42 publications

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“…In our study, moment arms were not directly correlated with muscle volumes, body size, or peak plantarflexion torques during walking in either young or older adults. Older adults in our study had slightly smaller moment arms than the young adults, as has been shown previously (Rasske and Franz, 2018 ), though the difference was not significant here.…”

Section: Discussionsupporting

confidence: 81%

Achilles Tendon Morphology Is Related to Triceps Surae Muscle Size and Peak Plantarflexion Torques During Walking in Young but Not Older Adults

Knaus

Ebrahimi

Martin

et al. 2020

Front. Sports Act. Living

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The interaction of the triceps surae muscles and the Achilles tendon is critical in producing the ankle plantarflexion torque required for human walking. Deficits in plantarflexor output are a hallmark of reduced mobility in older adults and are likely associated with changes in the triceps surae muscles that occur with age. Structural differences between young and older adults have been observed in the Achilles tendon and in the triceps surae muscles. However, less is known about how age-related differences in muscle and tendon morphology correspond with each other and, furthermore, how those morphology differences correlate with age-related deficits in function. The goal of this work was to investigate whether there is a correlation between age-related differences in triceps surae muscle size and Achilles tendon cross-sectional area (CSA) and whether either is predictive of ankle plantarflexion torque during walking. We used magnetic resonance imaging (MRI) to measure triceps surae muscle volumes and tendon CSAs in young (n = 14, age: 26 ± 4 years) and older (n = 7, age: 66 ± 5 years) adults, and we determined peak plantarflexion torques during treadmill walking. We found that individual muscle volumes as a percentage of the total triceps surae volume did not differ between young and older adults, though muscle volumes per body size (normalized by the product of height and mass) were smaller in older adults. Achilles tendon CSA was correlated with body size and muscle volumes in young adults but not in older adults. The ratio of tendon CSA to total triceps surae muscle volume was significantly greater in older adults. Peak ankle plantarflexion torque during walking correlated with body size and triceps surae volume in young and older adults but was correlated with tendon CSA only in the young adults. Structure-function relationships that seem to exist between the Achilles tendon and the triceps surae muscles in young adults are no longer evident in all older adults. Understanding mechanisms that determine altered Achilles tendon CSA in older adults may provide insight into age-related changes in function.

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Section: Discussionsupporting

confidence: 81%

Achilles Tendon Morphology Is Related to Triceps Surae Muscle Size and Peak Plantarflexion Torques During Walking in Young but Not Older Adults

Knaus

Ebrahimi

Martin

et al. 2020

Front. Sports Act. Living

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“…Since muscle strength decreases with aging (Narici et al, 2008), individualizing maximal isometric muscle forces in our musculoskeletal models would increase the plantarflexor and hip extensor muscle activations and therefore the plantarflexor and hip extensor muscle energy cost of walking. Furthermore, as reported for the ankle plantarflexors (Rasske and Franz, 2018), it might be that the hip muscle moment arms during walking are smaller in older than in young adults due to smaller three-dimensional shape changes (muscle bulging). However, since the Hill-type muscle models assume constant muscle thickness, this is overlooked in our musculoskeletal models (Zajac, 1989).…”

Section: Discussionmentioning

confidence: 82%

Achilles tendon stiffness minimizes the energy cost in simulations of walking in older but not in young adults

Delabastita

Groote

Vanwanseele

2020

Preprint

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Both Achilles tendon stiffness and walking patterns influence the energy cost of walking, but their relative contributions remain unclear. These independent contributions can only be investigated using simulations. We created models for 16 young (24±2 years) and 15 older (75±4 years) subjects, with individualized (using optimal parameter estimations) and generic triceps surae muscle-tendon parameters. We varied Achilles tendon stiffness and calculated the energy cost of walking. Both in young and older adults, Achilles tendon stiffness independently contributed to the energy cost of walking. However, overall, a 25% increase in Achilles tendon stiffness increased the triceps surae and whole-body energy cost of walking with approximately 7% and 1.5%, respectively. Therefore, the influence of Achilles tendon stiffness is rather limited. Walking patterns also independently contributed to the energy cost of walking because the plantarflexor (including, but not limited to the triceps surae) energy cost of walking was lower in older than in young adults. Hence, training interventions should probably rather target specific walking patterns than Achilles tendon stiffness to decrease the energy cost of walking. However, based on the results of previous experimental studies, we expected that the calculated hip extensor and whole-body energy cost of walking would be higher in older than in young adults. This was not confirmed in our results. Future research might therefore assess the contribution of the walking pattern to the energy cost of walking by individualizing maximal isometric muscle force and by using three-dimensional models of muscle contraction.Summary statementAchilles tendon stiffness and walking patterns independently contribute to the energy cost in simulations of walking in young and older adults. The influence of Achilles tendon stiffness is rather small.

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“…Yet, despite those limitations, the UsKin method seems to be most promising for future in vivo studies as it is not limited by range of motion, accounts for inter-individual AT MA differences, and is sensitive to influences of joint rotation and varying contraction intensities. Rightfully so, this ultrasound-based geometric method has emerged to a common approach to determine the dynamic AT MA within recent years 17,[20][21][22][23][24][25]27 . Realistic calculation of TS forces is not only a prerequisite to determine physiological force-length data but also to determine realistic muscle properties including force-velocity relations and elastic properties of muscles from measured external reaction forces or joint torques [51][52][53] .…”

Section: Discussionmentioning

confidence: 99%

“…(3) A geometric imaging method using motion tracking and ultrasound (UsKin). Thereby, an ultrasound probe (calibrated in space) is used to track the AT line of action [16][17][18][19][20][21][22][23][24][25][26][27] . Similar to the Experimental setup.…”

mentioning

confidence: 99%

Considerations on the human Achilles tendon moment arm for in vivo triceps surae muscle–tendon unit force estimates

Holzer

Paternoster

Hahn

et al. 2020

Sci Rep

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Moment arm-angle functions (MA-a-functions) are commonly used to estimate in vivo muscle forces in humans. However, different MA-a-functions might not only influence the magnitude of the estimated muscle forces but also change the shape of the muscle’s estimated force-angle relationship (F-a-r). Therefore, we investigated the influence of different literature based Achilles tendon MA-a-functions on the triceps surae muscle–tendon unit F-a-r. The individual in vivo triceps torque–angle relationship was determined in 14 participants performing maximum voluntary fixed-end plantarflexion contractions from 18.3° ± 3.2° plantarflexion to 24.2° ± 5.1° dorsiflexion on a dynamometer. The resulting F-a-r were calculated using 15 literature-based in vivo Achilles tendon MA-a-functions. MA-a-functions affected the F-a-r shape and magnitude of estimated peak active triceps muscle–tendon unit force. Depending on the MA-a-function used, the triceps was solely operating on the ascending limb (n = 2), on the ascending limb and plateau region (n = 12), or on the ascending limb, plateau region and descending limb of the F-a-r (n = 1). According to our findings, the estimated triceps muscle–tendon unit forces and the shape of the F-a-r are highly dependent on the MA-a-function used. As these functions are affected by many variables, we recommend using individual Achilles tendon MA-a-functions, ideally accounting for contraction intensity-related changes in moment arm magnitude.

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Aging effects on the Achilles tendon moment arm during walking

Cited by 23 publications

References 42 publications

Achilles Tendon Morphology Is Related to Triceps Surae Muscle Size and Peak Plantarflexion Torques During Walking in Young but Not Older Adults

Achilles Tendon Morphology Is Related to Triceps Surae Muscle Size and Peak Plantarflexion Torques During Walking in Young but Not Older Adults

Achilles tendon stiffness minimizes the energy cost in simulations of walking in older but not in young adults

Considerations on the human Achilles tendon moment arm for in vivo triceps surae muscle–tendon unit force estimates

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