What is the definition or description of: repetitive strain injury?

Overuse injury: Usually occurs when an activity that involves a repetitive motion such as running incurs more force than then the area is meant to withstand. For example, tennis elbow known as lateral epicondylitis occurs when the wrist and forearm are repetitively extended past the point of fatigue for the wrist extensor muscles. It creates pain due to inflammation but after 6 mos pain is due to degeneration.

Repetitive strain: "injuries of the musculoskeletal and nervous systems that may be caused by repetitive tasks, forceful exertions, vibrations, mechanical compression (pressing against hard surfaces), or sustained or awkward positions". Rsi is also known as cumulative trauma disorders, repetitive stress injuries, repetitive motion injuries or disorders, musculoskeletal disorders, and [occupational] overuse syndrome.