An exercise apparatus having a pair of speed control drums coaxial with a variable speed motor driven shaft is disclosed. A force control drum is mounted to a gear box via which the motor is linked to the shaft. A cable is wound about the force control drum, with one of the free ends of the cable being connected to a force spring. A user-controlled cable is wound about the speed control drums so that by pulling on the cable, the speed control drums rotate with respect to the shaft. Movement of the user controlled cable above a pre-set speed causes the force control drum to wind cable in a manner that extends the force spring. The apparatus permits the user to control both the magnitude of machine resistance encountered and the speed with which loads are obtained.