Muscle‐tendon morphology and function following long‐term exposure to repeated and strenuous mechanical loading

Abstract
We mapped structural and functional characteristics of muscle‐tendon units in a population exposed to very long‐term routine overloading. Twenty‐eight military academy cadets (age: 21.00 ± 1.1 yrs; height: 176.1 ± 4.8 cm; mass: 73.8 ± 7.0 kg) exposed for over 24 months to repetitive overloading were profiled via ultrasonography with a senior subgroup of them (n = 11; age = 21.4 ± 1.0 yrs; height = 176.5 ± 4.8 cm; mass = 71.4 ± 6.6 kg) also tested while walking and marching on a treadmill. A group of eleven ethnicity‐ and aged‐matched civilians (age = 21.6 ± 0.7 yrs; height = 176.8 ± 4.3 cm; mass = 74.6 ± 5.6 kg) was also profiled and tested. Cadets and civilians exhibited similar morphology (muscle and tendon thickness and cross‐sectional area, pennation angle, fascicle length) in 26 out of 29 sites including the Achilles tendon. However, patellar tendon thickness along the entire tendon was greater (p<0.05) by a mean of 16% for the senior cadets compared with civilians. Dynamically, cadets showed significantly smaller ranges of fascicle length change and lower shortening velocity in medial gastrocnemius during walking (44.0% and 47.6%, p<0.05 ‐ 0.01) and marching (27.5% and 34.3%, p<0.05 ‐ 0.01) than civilians. Furthermore, cadets showed lower normalised soleus electrical activity during walking (22.7%, p<0.05) and marching (27.0%, p<0.05). Therefore, 24‐36 months of continuous overloading, primarily occurring under aerobic conditions, leads to more efficient neural and mechanical behaviour in the triceps surae complex, without any major macroscopic alterations in key anatomical structures.
Main Authors
Format
Articles Research article
Published
2020
Series
Subjects
Publication in research information system
Publisher
Wiley-Blackwell
The permanent address of the publication
https://urn.fi/URN:NBN:fi:jyu-202004062673Use this for linking
Review status
Peer reviewed
ISSN
0905-7188
DOI
https://doi.org/10.1111/sms.13669
Language
English
Published in
Scandinavian Journal of Medicine and Science in Sports
Citation
  • Bissas, A., Havenetidis, K., Walker, J., Hanley, B., Nicholson, G., Metaxas, T., Christoulas, K., & Cronin, N. J. (2020). Muscle‐tendon morphology and function following long‐term exposure to repeated and strenuous mechanical loading. Scandinavian Journal of Medicine and Science in Sports, 30(7), 1151-1162. https://doi.org/10.1111/sms.13669
License
In CopyrightOpen Access
Additional information about funding
The study was supported by research development and infrastructure grants from Carnegie Faculty—Leeds Beckett University, while training and skills exchange were supported by an Erasmus + Staff Mobility agreement between Leeds Beckett University and University of Jyväskylä.
Copyright© 2020 Wiley-Blackwell

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