Sports and Exercise Medicine Lab.
Electrical Muscle Stimulation (EMS) has originally used to help people who are partially or completely immobile with rehabilitation. Recently, EMS was used as a training tool for athletes and healthy people to improve the muscular strength and function. Although many studies have been evaluated that EMS training has been proven to be effective in energy expenditure, body composition, and muscle function, it was still no certain whether it was the additional effects of EMS on non-athletic populations. Therefore, we aimed to investigate the acute (energy expenditure and metabolism) and chronic (body composition and muscle function) effects of the EMS training in female adults.
To identify the acute and chronic effects of EMS, we performed two experiments. In a first study, to verify the acute effects of EMS, ten females (age: 23.0±3.6 years) recruited in the randomized cross-over trials (weight-bearing training without EMS vs weight-bearing training with EMS). Oxygen consumption and blood lactate were measured to evaluate the energy expenditure and metabolism during each type of training. In a second study, 23 adults were randomly allocated to weight-bearing (WB-G; n=11) and EMS training group (EMS-G, n=12), and 21 participants (WB-G: n=10, 40.0±5.0 years; and EMS-G: n=11, 41.1±3.7 years) completed the 10 weeks intervention. A computer-tomography (CT) scan was used to evaluate visceral fat area of abdominis, and cross-sectional area (CSA) of thigh. The maximum muscle strength in knee joint (knee extension and flexion) was evaluated by Biodex System 3.
The acute EMS training showed higher energy expenditure per exercise than general weight-bearing training (WB-G: 72.1±10.3 kcal/session vs EMS-G: 87.0±17.0 kcal/session; p=0.018) and showed more lactate production during single bout of exercise (Lactate: 1.8±2.1 mmol/L vs 4.4±2.6 mmol/L; p=0.005). As a result of intervention during the 10 weeks based on effects of energy expenditure and metabolism, visceral fat area of the abdomen significantly reduced in EMS group (Pre: 96.4±33.5 cm2, Post: 90.4±30.8 cm2; p=0.017) with significant the interaction of time and group (Time×Group: p=0.017). In addition, isokinetic peak torque at high angular speeds (90°/s, 180°/s) was significantly increased after EMS training, but there was no significant difference between both groups.
We found that the EMS training contributes to higher energy expenditure and lactate production. In addition, these metabolic benefits of EMS may affect the reduction of the abdominal visceral fat area with long-term exercise. Consequently, these findings suggest that the change of body composition may attribute to improved energy expenditure caused by EMS application during weight-bearing training.