A strain injury is a tear in the connective tissue, usually either muscle, fascia, ligament or combination thereof, as a result of overstretching the area. Muscles are more prone to strain injuries during an eccentric contraction (muscle is lengthening with resistance) versus a concentric contraction (muscle is shortening with resistance). Tendons are less vascularized (less circulation) which makes them more prone to rupture/tearing at the area of least blood supply; usually the middle or at the musculotendinous junction (where the muscle attaches to the tendon).
Causes of Strain Injuries:
Levels of Strain Severity
Grade 1, Mild or First Degree Strain: minor tear to the musculotendinous unit with minimal discomfort when contracting or stretching the area. Symptoms include:
A period of total inactivity after a strain injury is not recommended as the affected muscles will shorten, restricting range of motion, and atrophy which will weaken the area. If the injury is not treated with some sort of soft tissue mobilization it will develop adhesions. Chronic inflammation from micro-tearing during the healing phase can also occur.
If you continue to overuse a muscle that has been strained, without giving it adequate time to heal, the area will be prone to repeated strains. It is possible to strain any muscle but the most frequently strained areas are: