What causes musculoskeletal strain?

Causes of Musculoskeletal Strain

Musculoskeletal strain is caused by mechanical problems, work or leisure injuries, age-associated changes, inflammatory diseases, and repetitive activities that create excessive force on muscles, tendons, and joints. 1

Primary Mechanical and Traumatic Causes

Direct mechanical injury occurs through excessive force application to musculoskeletal structures during work or recreational activities. 1 The European Union of Medical Specialists identifies mechanical problems and injuries sustained during occupational or leisure activities as fundamental causes of musculoskeletal conditions affecting bones, joints, periarticular structures, and muscles. 1

Repetitive Motion and Overuse

• Repetitive and forceful motions create microtrauma and overuse injuries to muscles and tendons, particularly when combined with awkward postures. 2
• The magnitude of resisting force (peak-stretch force) and the number of repetitive strains are the most critical factors producing muscle strain injury. 3
• Muscles crossing two joints, acting eccentrically, and containing high percentages of fast-twitch fibers are most susceptible to strain. 4
• Repetitive activities involving acceleration, pivoting movements, and changes in speed commonly cause adductor muscle strains and other musculoskeletal injuries. 1

Biomechanical Stress Patterns

• Prolonged seated or squatting positions create pressure on the femoral heads against the anterosuperior acetabular rim, causing coxofemoral joint stress. 1
• Repetitive mechanical loading from activities creates inflammation, microtrauma, and degenerative joint changes in affected structures. 5
• High-impact exercises (running, aerobic dancing) cause repeated impact stress on knees, ankles, and feet, while low-impact activities (walking, cycling, swimming) produce less joint stress. 1

Age-Related and Degenerative Causes

Age-associated changes represent a major causative factor, with osteoarthritis prevalence increasing dramatically after age 45. 1, 6 The burden of age-related musculoskeletal conditions increases with life expectancy, creating progressive structural deterioration. 1

• Intervertebral disk degeneration and osteoarthritis of vertebral joint facets result from cumulative biomechanical stressors, though these have multifactorial etiologies including genetics, age, sex, and body weight. 5
• Osteoporosis creates a 40% lifetime fracture risk for women over 50 years in Europe. 1

Inflammatory and Systemic Causes

Inflammatory diseases including arthritis of all kinds and systemic connective tissue disorders cause musculoskeletal strain through active disease processes. 1

• Chronic exposure to repeated strains leads to inflammation and fibrosis that persists for months even after rest. 3
• Inflammatory conditions affect not only the musculoskeletal system but often involve other organ systems, complicating management. 1

Occupational and Ergonomic Factors

Workplace conditions involving excessive repetitious motions, forceful exertions, and awkward postures create occupational repetitive strain injuries. 7, 2

• Occupational musculoskeletal disorders affect muscles, tendons, nerves, and blood vessels through sustained biomechanical stress. 8
• Work-related musculoskeletal problems account for up to 60% of early retirement and long-term sick leave claims. 1

Lifestyle and Activity-Related Factors

Sedentary lifestyle with prolonged sitting leads to hip flexor weakness through disuse atrophy and adaptive shortening. 9

• Inadequate warm-up before intense exercise and excessive fatigue increase susceptibility to muscle strain injury. 4
• Lifestyle factors including obesity, smoking (hazard ratio 1.5), and lack of physical activity contribute to musculoskeletal strain development. 6

Critical Clinical Considerations

The intensity and nature of impact during physical activity are the two most important factors determining injury frequency. 1 When evaluating causation, recognize that entheseal changes, osteoarthritic changes, and other musculoskeletal alterations have multifactorial etiologies influenced by genetics, age, sex, body weight, height, ancestry, pathological changes, and trauma—not solely activity patterns. 1

Muscle strain typically causes acute pain during strenuous activity, with diagnosis made primarily through history and physical examination rather than imaging. 4 The least active individuals face greatest risk for musculoskeletal injury during exercise, with sedentary persons showing 107 times baseline risk compared to 2.4 times for those exercising regularly five times weekly. 1