![]() ![]() ![]() Ĭoncentrate on hip abduction exercises to strengthen abductors. ![]() Weakness of these muscles results in an unstable pelvis while walking or while attempting to stand on one leg. The right hip abductors must supply an adequate contraction force to keep the pelvis from “falling into the space” created by the advancing left leg. Consider, for example, the demands placed on the right abductor muscles when the right leg is in the single-limb support phase of gait, as the left limb is swinging forward ( Fig. The most frequent demands placed on the hip abductors occur while walking. The axis of rotation for either pelvic action is in the anterior-posterior direction, through the center of the femoral head. (These muscles can be palpated midway between the greater trochanter and the iliac crest.) Similarly, eccentric activation of the right hip abductor muscles occurs while you slowly lower the left side of your pelvis. Verify on yourself that while standing only on your right leg, “hiking” the left side of your pelvis is accomplished by a relatively strong contraction of your right hip abductors. A more demanding (and common) activity imposed on these muscles occurs during closed-chain activities such as when the femur is fixed to the ground while standing on one leg (so-called single-limb support). This action typically places a relatively low demand on these muscles. With the pelvis held fixed, contraction of the hip abductor muscles abducts the femur away from the midline. The primary hip abductor muscles include the gluteus medius, gluteus minimus, and tensor fasciae latae the piriformis, sartorius, and superior fibers of the gluteus maximus are considered secondary hip abductors. Neumann PhD, PT, FAPTA, in Essentials of Kinesiology for the Physical Therapist Assistant (Third Edition), 2019 Hip Abductors Paul Jackson Mansfield DPT, BS, MS, Donald A. The position of inversion arranges the bones of the foot to their most stable position, forming a rigid lever for push-off. At mid to late stance, the subtalar joint moves toward inversion (supination), which resets the height of the medial longitudinal arch. These events create a more pliable position of the foot-an essential part of the shock-absorbing mechanism of early stance. After initial heel contact, the subtalar joint everts (pronates) as the medial longitudinal arch of the foot lowers. The kinematics of the subtalar joint provides an insight into this transformation. These joints help transform the foot from a pliable platform at early stance to a more rigid platform at late stance. While an individual is walking, the subtalar and transverse tarsal joints dictate much of the frontal plane kinesiology of the foot. ![]() Over time, this strain may over-stretch the medial collateral ligament. For instance, weakness of the hip abductors or excessive pronation of the foot, or both, may produce excessive valgus strain on the knee during the stance phase. It is interesting to note that instability of the knee may also arise from impairments at the hip or at the foot. A torn medial collateral ligament, for example, may lead to genu valgus, potentially altering normal gait mechanics. This natural stability may be lost through ligamentous injury. The knee is stabilized in the frontal plane primarily by its bony shape and by tension in the medial and lateral collateral ligaments. This abnormal response is known as a positive Trendelenburg sign and strongly suggests weakness of the hip abductor muscles. Without sufficient strength of the hip abductor muscles on the stance leg, the opposite side of the pelvis may drop excessively under the force of gravity. Activation of the stance leg’s hip abductor muscles normally holds the pelvis level, allowing the swing leg to advance toward the next step. When a given limb enters mid stance, the opposite leg is in its swing phase-not in contact with the ground. The hip abductor muscles stabilize the hip within the frontal plane during the single-limb support phase of walking. Neumann PhD, PT, FAPTA, in Essentials of Kinesiology for the Physical Therapist Assistant (Third Edition), 2019 Summary of the Frontal Plane Kinesiology of the Gait Cycle ![]()
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