Kinesiology of the Hip

Kinesiology of the Hip:

By Dr. Brent Brookbush, DPT, PT, MS, CPT, HMS, IMT

Prime Mover : The muscle that can produce the most force for a joint action. Generally, this is the muscle that will generate the most force during a joint action when exerting force against an external load.
Agonist : Muscles that perform a joint action, including the prime mover and synergists. That is, unlike the terms prime mover and synergist, agonist refers to all of the muscles that can perform a joint action.
Synergist : Synergists are muscles that assist the prime mover in performing a joint action. By definition, all agonists that are not the prime mover are synergists.
Antagonist : Muscles that oppose the agonists (including the prime mover and synergists) for a given joint action. That is, all of the muscles that can perform the opposing joint action.
Neutralizer : During a joint action, neutralizers are muscles that oppose the unwanted or ancillary joint motions that result from the force generated by the prime mover and/or synergists.
Fixator : Fixators are muscles that act to reduce or prevent movement of joints proximal to the joint in motion.
Stabilizer : The role of a stabilizer is to improve arthrokinematics by maintaining optimal alignment of joint surfaces during joint actions. Most often, these muscles are the most intrinsic muscles of a joint. For example, the muscles of the rotator cuff of the shoulder.

Hip Extension

Prime Mover: Gluteus maximus
Synergists: Biceps femoris (long head) , semitendinosus, semimembranosus , posterior head of adductor magnus
Antagonists: Psoas , iliacus , tensor fascia latae (TFL), rectus femoris , anterior adductors (especially pectineus) , sartorius
Neutralizers: Gluteus minimus and anterior fibers of gluteus medius neutralize external rotation force of gluteus maximus
Stabilizers: Deep rotators of hip
Fixators: Intrinsic stabilization subsystem , rectus abdominis , internal and external obliques , quadratus lumborum , erector spinae

Hip Flexion

Prime Mover: Psoas
Synergists: Iliacus , tensor fascia latae , rectus femoris , anterior adductors (especially pectineus) , sartorius
Antagonists: Gluteus maximus , biceps femoris (long head) , semitendinosus, semimembranosus , posterior head of adductor magnus
Neutralizers: The psoas and iliacus must work in concert with the TFL and anterior adductors to prevent internal and external rotation and/or abduction and adduction
Stabilizers: Deep rotators of hip
Fixators: Intrinsic stabilization subsystem , rectus abdominis , internal and external obliques , quadratus lumborum , erector spinae

Hip Internal Rotation

Prime Mover: Gluteus minimus
Synergists: Anterior fibers of gluteus medius , tensor fascia latae , semitendinosus, semimembranosus , anterior adductors
Antagonists – Gluteus maximus , posterior fibers of gluteus medius , biceps femoris (long head) , posterior head of adductor magnus , deep rotators of hip , sartorius
Neutralizers – Gluteus maximus , gluteus medius , and gluteus minimus prevent excessive adduction and flexion, especially during closed chain activities like an axe chop.
Stabilizers: Deep rotators of hip
Fixators: Intrinsic stabilization subsystem , rectus abdominis , internal and external obliques , quadratus lumborum , erector spinae

Hip External Rotation

Prime Mover: Piriformis
Synergists: Deep rotators of hip , gluteus maximus , posterior fibers of gluteus medius , biceps femoris (long head) , posterior head of adductor magnu s, sartorius
Antagonists: Anterior fibers of gluteus medius , gluteus minimus , tensor fascia latae , semitendinosus, semimembranosus , anterior adductors
Neutralizers: Hip flexors and anterior adductors may reduce propensity of external rotators to extend and abduct the hip
Stabilizers: Deep rotators of hip , gluteus medius , gluteus minimus
Fixators: Intrinsic stabilization subsystem , rectus abdominis , internal and external obliques , quadratus lumborum , erector spinae

Hip Abduction

Prime Mover: Gluteus medius
Synergists: Gluteus maximus (superior fibers) , gluteus minimus , tensor fascia latae , sartorius , vastus lateralis via fascial slips
Antagonists: Adductor magnus, pectineus, adductor brevis, adductor longus, gracilis , gluteus maximus (inferior fibers) , quadratus femoris
Neutralizers: The abductors of the thigh also contribute to rotation. A careful balance of strength and flexibility between internal and external rotators ensures optimal muscular synergies. The psoas , rectus femoris , pectineus , biceps femoris , semitendinosus, and semimembranosus prevent ancillary flexion and extension of the hip.
Stabilizers: Deep rotators of hip
Fixators: Intrinsic stabilization subsystem , rectus abdominis , internal and external obliques , quadratus lumborum , erector spinae

Hip Adduction

Prime Mover: Adductors
Synergists: Gluteus maximus (inferior fibers) , quadratus femoris , semitendinosus, semimembranosus
Antagonists: Gluteus maximus (superior fibers) , gluteus medius , gluteus minimus , tensor fascia latae , sartorius , vastus lateralis via fascial slips
Neutralizers: The adductors of the thigh also contribute to rotation. A careful balance of strength and flexibility between internal and external rotators ensures optimal muscular synergies. The psoas , rectus femoris , pectineus , biceps femoris , semitendinosus, and semimembranosus prevent ancillary flexion and extension of the hip.
Stabilizers: Deep rotators of hip
Fixators: Intrinsic stabilization subsystem , rectus abdominis , internal and external obliques , quadratus lumborum , erector spinae

Hip Horizontal Abduction

Prime Mover: Piriformis
Synergists: Deep rotators of hip , gluteus medius , gluteus minimus , tensor fascia latae , gluteus maximus
Antagonists: Pectineus, adductor brevis, adductor longus, adductor magnus (both heads), gracilis
Neutralizers: Hamstrings and hip flexors neutralize ancillary motion in the sagittal plane, TFL neutralizes external rotation force created by the piriformis and deep rotators of the hip .
Stabilizers: Deep rotators of hip , gluteus medius , gluteus minimus , pectineus
Fixators: Intrinsic stabilization subsystem , rectus abdominis , internal and external obliques , quadratus lumborum , erector spinae

Hip Horizontal Adduction

Prime Mover: Anterior adductors
Antagonists: Deep rotators of hip , gluteus medius , gluteus minimus , tensor fascia latae , gluteus maximus
Synergists: Posterior head of adductor magnus
Neutralizers: Hamstrings and hip flexors neutralize ancillary motion in the sagittal plane, and the posterior head of the adductor magnus neutralizes internal rotation force created by the anterior adductors.
Stabilizers: Deep rotators of hip , gluteus medius , gluteus minimus , pectineus
Fixators: Intrinsic stabilization subsystem , rectus abdominis , internal and external obliques , quadratus lumborum , erector spinae

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