A 2m tall athlete weighing 90kg is exercising the knee extensor muscles while sitting on a bench. A 30kg weight is placed on the leg 0.40m from the center of motion of the knee joint. (a) Calculate the moment the knee extensor muscles must counteract at full extension and 60 degree of knee flexion. Consider the weight of the lower leg and the foot separately, and use the anthropometric data given below to get the relevant properties needed for the calculations. In each case consider the muscular line of