"Kinesiology of the Hip: A Focus on Muscular Action"

Here are a few of the many interesting points discussed in this article by Dr. Neumann in this 2010 Research Review: 

-You must always include both cross-sectional area and moment arm length when assessing force and muscle action.

-The Psoas major acts as an important vertical stabilizer of the lumbar spine, especially in full hip extension, when the greatest passive tension is on the muscle.

-The posterior head of the adductor magnus is a primary extensor

-Co-activating the hip extensors and abdominals while passively stretching the hip flexors can provide an additional stretch on the hip flexors.

-Both the sartorius and long head of the biceps femoris act as secondary external rotators.

-Dynamic stability of the hip during high velocity rotation may be one of the primary functions of the short external rotators.

-The short external rotators provide acetabulofemoral articulation stability (similar to how the infraspinatus and teres minor provide stability at the glenohumeral joint)

-The Gluteus Max. is an important external rotator in closed chain kinematics (such as stopping and cutting).

-At 0 deg. of hip flexion, the Gluteus Max. Anterior fibers act as external rotators, BUT At 45 deg. of hip flexion, the Anterior fibers become internal rotators.

-The piriformis is an external rotator in full extension, but an internal rotator in hip flexion >90 degrees.

- Most adductors become hip extensors between 40 and 70 degrees of hip flexion (the exact degree is not known although research is being done on the topic.)

-The Gluteus Minimus tendon attaches to the Anterior and Superior Joint Capsule of the Hip Joint.

See Full Article Here

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