Kinesiology of the Hip: A Focus on Muscular Actions

The 21 muscles that cross the hip provide both triplanar movement and stability between the femur and acetabulum. The primary intent of this clinical commentary is to review and discuss the current understanding of the specific actions of the hip muscles. Analysis of their actions is based primarily on the spatial orientation of the muscles relative to the axes of rotation at the hip. The discussion of muscle actions is organized according to the 3 cardinal planes of motion. Actions are considered from both femoral-on-pelvic and pelvic-on-femoral perspectives, with particular attention to the role of coactivation of trunk muscles. Additional attention is paid to the biomechanical variables that alter the…