Effects of neuromuscular electrical stimulation of various frequencies and intensities of energy expenditure

Abstract

The purpose o f this study was to determine the effects o f neuromuscular electrical stimulation (NMES) o f various intensities (25, 50,75, and 100 mA) and frequencies (8, 12,20, 50 Hz) on energy expenditure o f the knee extensor muscles (KEM). Fourteen male university students between 20 and 24 years o f age were submitted to 5 min o f each intensity at each frequency during NMES on different days with the use o f a portable stimulator (Respond H, EMPI; impulse width of 300 microseconds; duty cycle: 55s on and 2s off) and adhesive electrodes (Pals Plus™, EMPI). Oxygen uptake was measured in the supine position at rest and during NMES o f both KEM. Energy expenditures (kcal. hr-1 .kg o f KEM -1) o f the four frequencies o f each intensity (mean : 25 mA= 1.8; 50 mA= 7.8; 75 mA= 21.6; 100 mA= 26.3) were not significantly different (p>0.05) and that of the different intensities of each frequency were significantly different (p<0.05- p<0.001) except in 50 Hz between 75 and 100 mA (p>0.05). The highest energy expenditure (28.1 kcal. hr-1 .kg o f KEM-1) was observed at a stimulation frequency o f 8 Hz (p>0.05) at an intensity o f 100 mA.