Consider a right punch (cross) from boxing (1):
hip extension at the rear leg causes a forward momentum of the body that has to be countered by an extension moment at the front knee. This hip extension is the source of much of the power of the punch, especially in the start of the punch.
However a punch is not a forward motion, as much as a rotation both of the pelvis and the thoracic spine:
we notice that the rear leg has moved from external rotation into internal rotation. This is performed as a pivot on the ball of the rear foot. During this phase of the punch the hip extensors and the internal hip rotators of the rear leg work together to produce the hip rotation. This phase (which precedes the images) is called "hip drive".
The phase when the punch is being delivered is called the "brake". During this phase the boxer has to counter forces trying to push him out of his stance. The pelvic rotation wants to rotate his front foot counter clockwise. He has to counter this by applying an internal hip rotator momentum (isometric) on the front leg. Likewise the pivoting of the rear leg causes a rotational momentum that wants to rotate his rear foot even further counter clockwise. He has to counter this with an external hip rotator momentum (isometric) on the rear leg:
The biomechanics of a javelin throw (2) is quite similar to those of a boxing punch:
"The right hip acts as the “accelerator”, and the left side acts as the “brakes.”"
"The acceleration of the right hip comes from acetabular/femoral internal rotation (AFIR) and extension."
"The brakes of the hip drive are left side AFIR, abduction, and extension."
This therefore seems like a fundamental human movement pattern. Typically this movement is not trained in common strength training programs. Most other fundamental human movement patterns like the hinge and squat are. Following the philosophy of "use it or loose it" I think this may be a bad thing.
I am thinking that this maybe causes weak hips which in turn causes tight hips?
Should one incorporate rotation exercises into strength training? If so, how?
Further during running hip rotation also play an important role. However when running the thoracic rotation is in the opposite direction of the pelvic rotation (3):
"Rotation of the hips (pelvis) in the transverse plane (think: spinning around in circles) is the key to running faster and more efficiently."
"If there is minimal transverse hip rotation, the role of the glute max is minimized."