Electrical muscle stimulation (EMS) devices have been advertised to increase muscle strength, decrease body weight and body fat, and improve muscle firmness and tone. This study sought to test those claims. Twenty-seven college-aged volunteers were assigned to either an EMS (n = 16) or control (n = 11) group. The EMS group underwent stimulation 3 times per week for 8 weeks following the manufacturer's recommendations. The control group underwent concurrent “stimulation” sessions, however the machines had been altered so that no current was being delivered to subjects. Bi-laterally, the muscles stimulated included the hamstrings, quadriceps, bicepts, triceps, and abdominals. An identical test battery was given before and after the study, with evaluators blinded to group assignment. Tests included body weight, body fat (via akinfolds), girths (10 sites), isometric and isokinetic strength (biceps, triceps, hamstrings, quadriceps), and appearance (via photographs from the front, back, and side views). All photographs were scored by two independent observers. EMS had no significant effect on body weight or body fat, skinfold measurements over the stimulated muscles, girth measurements of the stimulated areas, isometric or isokinetic strength, or physical appearance. Selected data included: body weight (kg) - EMS pre = 72.8, post = 72.8, C pre = 71.7, post = 71.1; sum of skinfolds (mm) - EMS pre = 122.4, post = 123.5, C pre = 119.4, post = 117.6; quad strength (ft lbs) - EMS pre = 143.0, post = 141.0, C pre = 137.5, post = 140.8; waist girth (cm) - EMS pre = 78.0, post = 78.6; C pre = 80.4, post = 79.3). Thus, claims relative to the effectiveness of EMS are not supported.
