A method and apparatus for conditioning muscles during sleep. The apparatus
includes microminiature electrical stimulators that are injected into the
muscles to be exercised and a system of transmission coils located in or
on the mattress of a bed. The transmission coils transmit power and
command signals to the implanted electrical stimulators while the patient
sleeps or rests. The implanted electrical stimulators can be programmed so
as to produce the desired pattern of muscle exercise without producing
cutaneous sensations that would disturb the patient.