 Electrical foot stimulation was produced by surface electrodes placed on the sole of the foot over the plantar muscle group. Electrical stimulation was delivered by the FocusTM Neuromuscular Stimulation System, Empi, Inc. St. Paul, MN. The crucial stimulus parameters were: biphasic symmetrical square wave at 50 pulses per second, phase duration of 300 microseconds, a starting ramp up time of 2 seconds and a finishing ramp down time of 2 seconds per stimulation cycle, and a stimulation cycle of 12 seconds on and 48 seconds off per minute. Stimulation was increased to an intensity just sufficient to create a slight visible muscle twitch. This level of intensity caused no evident discomfort in any of the subjects in our first study. Subjects were continually monitored throughout this study for any indication of discomfort. 