(1) Calculate the reactive force and reactive muscle moment at the knee for a seated leg extension, with a weight of 35, 45, and 55 lbs. Assume that the leg is held at an angle ?

(2) Read the accompanying article on squat technique. Calculate and compare the joint reactive forces (Rj) and reactive moments (Mj) at the hip, knee, and ankle for the two squat forms illustrated. Assume the subject is lifting an unloaded bar (45 lbs), and his posture is symmetric.