Abstract: The apparatus comprises reciprocating footpads to which are coupled a D.C. electric motor. A D.C. power supply and control means are assocated with the motor to vary the voltage delivered to it. A load sensor and isolator sense the voltage supplied by the power supply, and also sense the voltage present at the motor terminals during periods when no power is being supplied to the motor by the power supply. The sensor and isolator also isolate the motor from the power supply during certain periods, namely when the power supplied to the motor by the exerciser is greater than that supplied by the power supply. An electrical load circuit and load set vary the motor load.