Abstract: Safety features for a continuous motion therapy system of the type including a carriage for supporting a patient's limb, a drive unit for driving the carriage through a range of reciprocal angular movement, first and second channel neuromuscular stimulators for applying electrical stimulation to muscles of a patient's limb, and a controller for controlling the drive unit and stimulators. Both stimulator channels must be turned OFF after the controller is powered up before either stimulator channel will operate. The drive unit is enclosed by a cover. When pressure on the cover is sensed, the controller stops and reverses the direction of the carriage. The drive unit includes a drive motor which is coupled to the carriage by a linkage. Limit switches provide limit signals when the linkage reaches predetermined limit positions. In response, the controller stops and reverses direction of the carriage.