What is a hamstring strain?

• A. A tear of the ACL
• B. A meniscal tear
• C. An injury to the hip extensor/knee flexor group
• D. An injury to the quadriceps

Answer: (C)

A hamstring strain is an injury to the hamstring muscle group, the muscles at the back of the thigh that cross both the hip and knee. Because they act as hip extensors and knee flexors, these muscles are stressed when you sprint or perform rapid accelerations and decelerations, especially as they lengthen eccentrically to slow the leg during late swing. A strain involves tearing of muscle fibers or at the musculotendinous junction within this group. This description precisely distinguishes it from injuries to ligaments like the ACL, cartilage like the menisci, or the front-of-thigh knee extensors (the quadriceps).