Prolonged electrical muscle stimulation exercise improves strength and aerobic capacity in healthy sedentary adults

Abstract

This investigation evaluated training responses to prolonged electrical muscle stimulation ( EMS) in sedentary adults. Fifteen healthy subjects ( 10 men, 5 women) with a sedentary lifestyle completed a 6- wk training program during which they completed an average of 29 1- h EMS sessions. The form of EMS used by the subjects was capable of eliciting a cardiovascular exercise response without loading the limbs or joints. It achieved this by means of inducing rapid, rhythmical contractions in the large leg muscles. A crossover study design was employed with subjects undergoing their habitual activity levels during the nontraining phase of the study. The training effect was evaluated by means of a treadmill test to determine peak aerobic capacity [ peak oxygen consumption ( V-O2)], a 6- min walking distance test, and measurement of body mass index ( BMI) and quadriceps muscle strength. At baseline, the mean values for peak V-O2, 6- min walking distance, quadriceps strength, and BMI were 2.46 +/- 0.57 l/ min, 493.3 +/- 36.8 m, 360.8 +/- 108.7 N, and 26.9 +/- 3.4 kg/m(2), respectively. After training, subjects demonstrated statistically significant improvements in all variables except BMI. Peak V-O2 increased by an average of 0.24 +/- 0.16 l/ min ( P < 0.05), walking distance increased by 36.6 +/- 19.7 m ( P < 0.005), and quadriceps strength increased by 87.5 +/- 55.9 N ( P < 0.005); we did not observe a significant effect due to training on BMI ( P > 0.05). These results suggest that EMS can be used in sedentary adults to improve physical fitness. It may provide a viable alternative to more conventional forms of exercise in this population.