A method selects a patient for therapeutic electrical stimulation of selected muscles. The patient is provided with a portable electrical pulse generator, which is coupled via an electrode cable assembly to intramuscular simulation electrodes percutaneously implanted directly into selected muscles of a patient. A clip connects the electrical pulse generator to the patient so that the electrical pulse generator and the electrode cable assembly coupled to the intramuscular stimulation electrodes ambulate with the patient. The electrical pulse generator is operated to apply therapeutic electrical stimulation of the selected muscles during ambulation of the patient. Periodically, the battery is replaced by releasing a battery access cover.