Thursday, February 2, 2012

Movement and Muscles at the Hip
 internal and external rotation

biggie internally rotates her leg at the hip biggie externally rotates her leg at the hip

What movements happen at this joint?

So for actual rotation of the leg, the leg hangs straight and the ball of the femur turns around like Linda Blair in the socket of the pelvis. Internal rotation is when the leg turns in toward the hip, and external rotation is when the leg turns out away from the hip.

A way to isolate internal and external rotation is to flex your lower leg at the knee and point your knee straight down, then flip your foot out for internal rotation and flip it in for external rotation.

For skaters, you internally rotate your leg for things like plow stops and externally rotate for mohawks and spreadeagles. I have heard "my legs don't do that" from a lot of students. I think it's helpful to think not about freezing your hips in a turned out position, but about how your hips naturally move in and out of that position. That said, I'm pretty flexible at the hips and I might just be talking out of my butt.

What muscles make these movements happen?

hip internal rotation hip external rotation anterior hip external rotation posterior

The anatomy chapter gives as the muscles that internally rotate your leg at the hip your gluteus medius (anterior fibers) and tensor fascia latae, and slightly your semimembranosus and semitendinosus, which is what I have drawn above; however, the kinesiology chapter also gives the adductor brevis, adductor longus, gluteus minimus, and pectineus and also says that from anatomical position, there are no true primary internal hip rotators. As you flex your leg, the above muscles are in a better position to work as internal hip rotators. I dunno. Just from where they're positioned, smaller glutes and tensor fascia latae and adductors all make sense to me.

The muscles that externally rotate your leg at the hip are a lot: anteriorly, your iliopsoas, sartorius, and pectineus and posteriorly you have your glutes plus six external hip rotators: piriformis, gemellus superior, gemellus inferior, obdurator interus, obdurator externus, and quadratus femoris.

What exercises make these muscles work?

Resisted external rotation will work the external rotators.

Related Posts Plugin for WordPress, Blogger...