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Updated: Jun 27, 2026
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Published on: October 3, 2025
Adaptive stretch-shortening contractions: diminished regenerative capacity with aging
Brent A Baker1, Melinda S Hollander, Robert R Mercer
1National Institute for Occupational Safety and Health (NIOSH), Health Effects Laboratory Division, Morgantown, WV 26505, USA.
Summary
Aging impairs skeletal muscle
Area of Science:
- Skeletal Muscle Physiology
- Aging Research
- Exercise Science
Background:
- Skeletal muscle remodeling and regeneration are crucial for adaptation to mechanical loading.
- Aging is associated with declines in muscle function and regenerative capacity.
- Understanding age-related changes in muscle response to exercise is vital.
Purpose of the Study:
- To investigate age-related differences in skeletal muscle remodeling and regeneration after stretch-shortening contractions (SSCs).
- To quantify changes in muscle performance and morphology in young and old rats following SSCs.
Main Methods:
- Young and old rats were subjected to acute adaptive SSCs.
- Muscle performance and morphology were assessed at 6, 24, 48, 72, and 120 hours post-exposure.
- Developmental myosin heavy chain (MHCdev+) labeling was used to assess muscle regeneration.
Main Results:
- Old rats exhibited decreased muscle performance throughout the 120-hour recovery period compared to young rats.
- Edema was increased in old rats at 120 hours post-exposure.
- While both age groups showed MHCdev+ labeling, old rats had diminished labeling, indicating reduced regenerative capacity.
Conclusions:
- Aging significantly limits the skeletal muscle's ability to remodel and regenerate following mechanical loading.
- Reduced regenerative capacity in older adults may impair skeletal muscle adaptation to exercise.
- These findings highlight the impact of aging on muscle's response to physical stimuli.
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