Strains

There are multiple matches for strains, including a soft tissue injury, a genetic variant, and a mechanical property:

Soft tissue injury: A strain is a soft tissue injury that can be acute or chronic, and can affect a muscle or tendon. A sprain is the equivalent injury to a ligament.
Genetic variant: A strain is a genetic variant, subtype, or culture within a biological species. Strains are often considered artificial concepts, and are characterized by a specific intent for genetic isolation.