Injury and adaptive mechanisms in skeletal muscle.

Area of Science:

• Biomechanics
• Muscle Physiology
• Occupational Health

Background:

• Work-related musculoskeletal disorders (MSDs) are a major cause of lost-time injuries in the US, often due to overexertion and repetitive motion.
• Extensive research has investigated contraction-induced skeletal muscle injury, focusing on biomechanical loading factors like force, repetition, and duration.
• Recent studies highlight the influence of aging on muscle injury susceptibility and the body's regenerative capabilities.

Purpose of the Study:

• To review contraction-induced skeletal muscle injury.
• To examine the effects of repetitions, range of motion, work-rest cycles, and aging on muscle injury and adaptation.
• To differentiate between physiological responses to overt injury versus adaptation and discuss skeletal muscle's adaptive capacity.

Main Methods:

• Literature review focusing on contraction-induced skeletal muscle injury.
• Analysis of biomechanical loading signatures (velocity, range of motion, repetitions, force, work-rest cycle, exposure duration).
• Examination of aging effects on muscle injury, regeneration, and adaptation.

Main Results:

• Skeletal muscle possesses an inherent capability to adapt to mechanical loading under specific exposure signatures.
• Physiological phenomena distinct to overt muscle injury versus adaptive responses are identifiable.
• Aging significantly influences muscle susceptibility to injury and its regenerative pathways.

Conclusions:

• Repeated high-intensity mechanical loading is a promising strategy to mitigate sarcopenia.
• Targeted exercise may be the most effective physical activity to counteract workplace musculoskeletal dysfunction.
• Understanding muscle adaptation is key to preventing and treating work-related injuries.