Consider an individual who sits on a bench and performs a kn…

Consider an individual who sits on a bench and performs a knee-extension exercise (see figure below). The person is rehabilitating a knee injury and has a mass that can be attached to the shank (lower leg) to vary the difficulty of the exercise.  A) Which would require a stronger quadriceps (knee extensor muscle) contraction: performing the exercise with the mass attached at the ankle (as shown) or in the middle of the shank? Why? B) To lift the mass, would a positive or negative quadriceps (i.e., knee extensor muscle) torque need to be generated?