Here is another video from my friend and physical therapist Mike Kelly. This video describes the function and muscular interactions of the lower extremity. The video provides information about the critical importance of hip strength during functional activities. Hip strength provides the lower extremity with the strength and stability for gait, running, squatting and for balance. Hip strength The video demonstrates both non-weight bearing and weight bearing activities for hip strengthening. The weight bearing activities also help increase strength in functional planes.