Age-related changes to triceps surae muscle-subtendon interaction dynamics during walking

Push-off intensity is largely governed by the forces generated by the triceps surae (TS) muscles (gastrocnemius-GAS, soleus-SOL). During walking, the TS muscles undergo different fascicle kinematics and contribute differently to biomechanical subtasks. These differences may be facilitated by the Ach...

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Bibliographic Details
Published in:Scientific reports 2021-10, Vol.11 (1), p.21264-21264, Article 21264
Main Authors: Clark, William H., Franz, Jason R.
Format: Article
Language:English
Subjects:
631/443/7
692/698/1671
692/698/1671/1668
692/698/1671/1835
Achilles tendon
Achilles Tendon - physiology
Adult
Age
Age Factors
Aged
Aging
Ankle Joint - physiology
Biomechanical Phenomena
Heterogeneity
Humanities and Social Sciences
Humans
Kinematics
Middle Aged
multidisciplinary
Muscle, Skeletal - physiology
Muscles
Musculoskeletal Physiological Phenomena
Older people
Science
Science (multidisciplinary)
Tendons - physiology
Triceps surae muscle
Walking
Young Adult
Young adults
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Summary:Push-off intensity is largely governed by the forces generated by the triceps surae (TS) muscles (gastrocnemius-GAS, soleus-SOL). During walking, the TS muscles undergo different fascicle kinematics and contribute differently to biomechanical subtasks. These differences may be facilitated by the Achilles tendon (AT), which is comprised of subtendons that originate from the TS muscles. We and others have revealed non-uniform displacement patterns within the AT—evidence for sliding between subtendons that may facilitate independent muscle actuation. However, in older adults, we have observed more uniform AT tissue displacements that correlate with reduced push-off intensity. Here, we employed dual-probe ultrasound imaging to investigate TS muscle length change heterogeneity (GAS–SOL) as a determinant of reduced push-off intensity in older adults. Compared to young, older adults walked with more uniform AT tissue displacements and reduced TS muscle length change heterogeneity. These muscle-level differences appeared to negatively impact push-off intensity—evidenced by between-group differences in the extent to which TS muscle length change heterogeneity correlates with mechanical output across walking tasks. Our findings suggest that the capacity for sliding between subtendons may facilitate independent TS muscle actuation in young adults but may restrict that actuation in older adults, likely contributing to reduced push-off intensity.
ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-021-00451-y