THE FUNCTIONAL ANATOMY OF THE ADDUCTOR MUSCLES Hip adduction The principle role of the adductors is to adduct the hip. These mus- cles play an important role in activities such as climbing a rope or horse riding which require hip flexion and adduction.
Hip flexion and extension In addition to their role in adducting the hip, the adductor muscles can also flex the extended hip and can extend the flexed hip (10). For example in activities such as climbing up hill when the hip is flexed, the adductor muscles are forceful hip extensors. The change from flexor to extensor action varies with the individual muscles between 50-70º of hip flexion (18).
Hip rotation The adductor muscles also have the ability to assist in hip rotation. When the hip is flexed the adductor muscles rotate the hip medial- ly and when the hip is extended, the adductors rotate the hip lat- erally (10).
Adductor magnus is the main adductor muscle which assists in hip
rotation. Owing to the muscle fibre arrangement, adductor magnus has two functions. Adductor magnus is always a lateral rotator of the hip by the fibres which attach into the linea aspera. The fibres which attach to the adductor tubercle are short and horizontal and rotate the hip medially (19).
ROLE OF THE ADDUCTORS IN THE GAIT CYCLE The adductor muscles have an important role in the gait cycle. They assist in pelvic stabilization, moderating the interplay of forces between abduction and body weight (20). The adductors limit the motion of the body’s centre of gravity and therefore significantly decrease energy expenditure (32).
The adductors have four main activities during gait: 1. INITIAL CONTACT – concentric activation to advance the pelvis in relation to the limb in stance phase (32) 2. BEGINNING STANCE PHASE – the adductor muscles are antago- nists of the hip abductors – gluteus medius, and minimus and ten- sor fascia lata 3. STANCE PHASE – minor eccentric activation throughout the stance phase in order to prevent excessive hip abduction produced by the gluteus medius and gluteus minimus