Effect of Supplemental Electrical Stimulation on the Development of Strength, Vertical Jump Performance and Power

The purpose of this study was to determine whether short-term weight training supplemented with electrical stimulation (ES) increases muscular strength, vertical jump performance and power more than weight training alone. Thirty-three subjects were divided into three groups: WT supplemented with ES (Group 1), n = 13; weight training only (Group 2), n = 12; and control (Group 3), n = 8. Weight training consisted of performing 10 exercises including the parallel squat using free weights, three days per week for five weeks. In addition, Group 1 was stimulated with ES of both quadriceps three times per week. ES consisted of 10 maximal tolerated l0-second isometric contractions with 60 seconds of rest between contractions. A symmetrical biphasic square wave with a phase duration of 200 microseconds and a pulse rate of 50 pulses per second was used. Muscular strength was assessed using a one-repetition maximum parallel squat. Power was assessed using vertical jump scores that were converted using the Lewis formula. After training MS was not significantly different (p > 0.05) between the two experimental groups (20.6 percent increase for Group 1 und 20.7 percent increase for Group 2). Vertical jump performance was not significantly (p > 0.05) different between the two experimental groups (3.0 percent increase for Group 1 and 7.5 percent increase for Group 2). However, Group 2 (5.7% increase) had a significantly (p < 0.05) greater power than Group 1 (3.1 percent increase). In conclusion, short-term weight training supplemented with ES does not appear to enhance muscular strength, vertical jump performance or power more than weight training alone.