Lesson 15: Hamstrings and Adductors

This course describes the hamstring muscles (located on the posterior thigh) and the adductor muscles (located on the inner thigh). The hamstrings include the long head of the biceps femoris, the short head of the biceps femoris, the semitendinosus, and the semimembranosus. These muscles contribute to hip extension (e.g. squats), knee flexion (e.g. leg curls), tibial external rotation (e.g. feet turn out), and tibial internal rotation (e.g. toe-in gait). The adductors include the pectineus, adductor brevis, adductor longus, adductor magnus, and gracilis. These muscles contribute to hip adduction (e.g. squeezing legs together), hip flexion (e.g. mountain climbers), and hip internal rotation (e.g. functional valgus a.k.a. knees bow in). Note, these muscles also play a role in maintaining optimal posture and optimal arthrokinematics of the hip and knee joint. Sports medicine professionals (personal trainers, fitness instructors, physical therapists, massage therapists, chiropractors, occupational therapists, athletic trainers, etc.) must be aware of the hamstring and adductor muscles for analysis of human movement, and the development of sophisticated exercise programs and therapeutic (rehabilitation) interventions. Further, this course is essential knowledge for future courses discussing detailed anatomy like neural innervations (e.g. obturator nerve, sciatic nerve, etc.), the synergistic function of these muscles with other hip muscles (e.g. adductor muscles acting as a hip flexor along with the psoas, iliacus, etc.), injury (e.g. adductor muscle strain, hamstring muscle strain, hip impingement syndrome, etc.), and sports performance (e.g. muscle strength of the lower extremity/lower limb).

Caption: The location of the semitendionsus and semimembranosus