what is an antagonist muscle
antagonistic muscle - (physiology) a muscle that opposes the action of another; the biceps and triceps are antagonistic muscles. muscle, musculus-one of the contractile organs of the body. agonist-a muscle that contracts while another relaxes; when bending the elbow the biceps are the agonist.ntagonistic muscle - (physiology) a muscle that opposes the action of another; the biceps and triceps are antagonistic muscles. muscle, musculus-one of the contractile organs of the body. agonist-a muscle that contracts while another relaxes; when bending the elbow the biceps are the agonist.