Biomechanics Blog #1

An action that is part of my daily life is squatting to sit in a chair. When you start, you are standing upright. The end position is a supported squat sitting in a chair. The hips plane of motion is saggital and the axis of rotation is frontal.  The knees follow suit and the plane of motion is saggital and the axis of rotation is frontal. In osteokinematic terms, the knees are producing flexion when squatting. Arthrokinematic movement at the knee joint is the roll and slide. The prime movers for this action of sitting in a chair are the gluteal muscles. They move eccentrically when squatting down and when returning to the standing position they are concentric.