Muscle Forces at the Hip during Squatting Exercise

INTRODUCTION: Little is known about the forces in the muscles spanning the hip, and in particular, the forces in the deep muscles that contribute to both mobility and stability of the joint. Understanding the force in the muscles spanning the hip is motivated by the high incidence of injury and degenerative disease at the hip, and the frequency of its surgical treatment. Moreover, recent advances in hip arthroscopy have renewed interest in understanding how the muscles contribute to hip stability and joint load. The stability of the hip during activity is achieved through a balance of bone, muscle, and external forces. Unfortunately, direct measurement of hip muscle forces in vivo is unworkable. Furthermore, studies utilizing instrumented hip prostheses to measure hip joint loads cannot be used to infer muscle force, or applied to the normal or injured joint. Alternatively, musculoskeletal modeling allows muscle and joint loads to be obtained non-invasively. PIRIFORMIS