Overuse injuries – think muscle strains, tennis elbow, and rotator cuff tears – are a considerable problem in the United States, especially among young athletes. But while commonly associated with sports, overuse injuries – particularly those involving muscle strains – also affect significant numbers of workers whose jobs involve manual labor.
High-force, high-repetition movements, such as those involved in heavy lifting, create microinjuries in muscle fibers. Muscle tissue responds by making small repairs to the damaged fibers. But over time, with repetition of injury, healing capacity becomes overwhelmed, and microinjuries progress to fibrosis – the replacement of muscle tissue with connective tissue. Fibrosis ultimately weakens muscles and can put pressure on nerves, causing pain.