The present invention relates generally to an apparatus for exercising human muscles. It uses the electrically stimulated antagonist muscle force to resist the voluntary contracting agonist muscle. This method induas both eccentric contraction of antagonist muscle and concentric contraction of agonist muscle, which has been referred to as “closedkinetic-chain exercise”. It allows a person to receive closed-kinetic-chanin exercise at a comfortable posture and prevents osteoporosis.
This study was performed to determine the electrical stimulated antagonist muscle force as a resistance of the voluntary contracting agonist muscle. Maximum electrically stimulated muscle force indicated 26% to voluntary muscle force with knee flexion, and the force ratio of antagonist muscle to agonist muscle varies according to the combination of muscles and knee joint angle.