The Science of Groin Strains

Groin strains involve injury to the adductor muscle group, which includes the adductor longus, magnus, brevis, gracilis, and pectineus. The adductor longus is most frequently injured (62-90% of cases), typically at the musculotendinous junction where muscle fibers transition to tendon. These injuries occur during high-velocity movements when the muscle undergoes eccentric contraction - lengthening under load. The mechanism typically involves forceful hip adduction against an abduction force, or sudden acceleration during sprinting. Sports like soccer, hockey, and football place athletes at highest risk due to the rapid direction changes, kicking motions, and explosive movements required. When the adductor muscle-tendon complex is overloaded beyond its capacity, microscopic tears develop in the muscle fibers. In acute strains, this creates immediate pain and functional limitation. When inadequately rehabilitated or subjected to chronic overload, the tissue can develop degenerative changes including enthesopathy (tendon attachment inflammation), bone marrow edema, and in severe cases, complete rupture requiring surgical repair. According to the 2014 Doha Agreement classification system, groin strains fall under "adductor-related groin pain" - characterized by tenderness over the adductor muscles and pain provoked by resisted adduction testing. This classification helps distinguish adductor strains from other groin pain causes like hip joint pathology, inguinal canal issues, or pubic bone stress.