EMS Training Pants

• Medicine (2023) 102:4

1. Introduction: Electrical muscle stimulation (EMS) has long been used as a complementary method of full-body training. [3,4] It artificially activates muscles through various electrical impulses delivered to the muscles via electrodes. As a result, the impulses trigger involuntary muscle contractions, which produce similar muscle contractions and relaxations as during conventional exercise, but without the strain.. [5] Specifically, it was designed to facilitate passive activation of a large number of motor muscles and induce synchronous contraction of muscle fibers, with the goal of increasing or maintaining muscle mass. [6–8] Recent advances in EMS technology have led to the development and implementation of relatively inexpensive and portable EMS devices for both home and commercial users. Previous studies have demonstrated the effectiveness of EMS on muscle function and physical performance in a variety of populations, including healthy young adults, the elderly, and patients with muscles that are underperforming due to trauma. (This is the case for the gluteal muscles in wheelchair users, for example.)

In particular, EMS is a supportive and effective rehabilitation method for patients with impaired physical performance or elderly people with low physical activity. Although conventional strength training is the most recommended for muscle mass gain, people who attend traditional gyms are often discouraged by a fast pace of life or low motivation. In these situations, EMS offers the opportunity to increase adherence to an exercise program[10] and improve patients’ body composition and physical strength. [4] Researchers have reported that EMS improves quadriceps strength and lower limb function in frail older patients with acute heart failure,[11] preserves muscle mass and function in patients with mobility impairment,[12] improves balance and reduces the risk of falls in the elderly,[13] reduces deltoid atrophy after arthroscopic rotator cuff repair,[14] and improves quadriceps strength and reduces pain in patients with knee osteoarthritis. [15] However, there is limited research on the effectiveness of EMS, especially in intensive care patients, which requires further research. [8,16]

EMS training has also been widely used in healthy and fit individuals and has been applied to competitive athletes. [17] Some studies have investigated the effects of EMS training on elite athletes, such as rugby, ice hockey, and basketball players, and have reported positive effects on muscle-related outcomes. [18–20] In addition, EMS studies have been conducted in untrained individuals. In recent studies, EMS application can effectively activate the superficial abdominal muscles[21] and increase the cross-sectional area of the lateral abdominal wall and rectus abdominis, as well as lumbopelvic control in healthy individuals. [22] In addition, Nishikawa et al. demonstrated that EMS can induce different distributions of quadriceps muscle activation from 50% and 70% maximal voluntary contractions, as measured by surface electromyography. [23] A systematic review and meta-analysis showed that it appears to have positive effects on muscle mass and strength parameters, but not on body fat mass. [4] However, the reported effects of EMS are partly compromised by factors such as the pre-trained status of the subjects, the lack of standardization of methods, or the intervention protocols. For example, a recent study compared the effects of EMS, conventional strength training, and EMS with conventional exercise (STEMS) on elbow flexion or muscle thickness after 8 weeks. Despite many previous studies, it is reasonable to assume that EMS should not be considered a substitute for conventional exercise training per se, as exercise itself not only improves muscle function but also has positive effects on endothelial function, cardiopulmonary fitness, and cognitive function. [24] The aim of this study was to evaluate the immediate clinical effects of STEMS compared to conventional exercise in healthy non-athletic adults by analyzing muscle thickness, various physical abilities, and body composition over an 8-week period of physical training. To obtain more objective results We conducted a randomized, controlled trial among groups of similar age groups using well-controlled training. In addition, we analyzed the effects of EMS on 3 aspects: physical performance, muscle thickness, and body composition. We hypothesized that STEMS would have additional advantages over conventional ST, as EMS may induce additional muscle fiber recruitment and produce greater changes after training.

2. Methods: This study was a single-blind (outcome assessor), prospective, randomized controlled trial using a parallel-group design conducted at a single center from January 2022 to February 2022. Forty-one healthy young volunteers were recruited and randomized into 2 groups: a group (n = 21) that received 8 weeks of strengthening training with EMS (S + E group) and a group (n = 20) that received 8 weeks of strengthening training alone (S group). A computer-generated random assignment list was used and the randomization results were blinded to the assessors. The primary outcome measure was changes in ultrasound muscle thickness, including abdominal, gluteal, and hip muscles. Secondary outcomes assessed changes in physical performance and body composition. All assessments were performed twice: before the intervention and after the 8-week intervention.

2.1. Participants: The sample size was calculated using Gpower 3.1. An effect size of 0.25, a probability of error of 0.05, and a power of 0.90 were defined as 38 participants. Considering the dropout rate of 10%, we recruited 41 healthy subjects (male = 17, female = 24). Inclusion criteria were as follows: age 20–25 years, no competitive sports, no spinal surgery or persistent low back pain, no medical conditions affecting muscle metabolism such as myopathy, and no medical history that would be affected by EMS, such as epilepsy or pacemaker insertion. All participants provided written informed consent before participation. The study was approved by the Institutional Review Board of Korea University Anami Hospital (2021AN0557). The CONSORT diagram is shown in Figure 1.

2.2. Strength training protocol: During the intervention period, all participants performed 30 minutes of strength training 3 times a week (Monday, Wednesday, and Friday) at the Yangon University gym for 8 weeks. Each training program included an additional 5 minutes of warm-up and cool-down periods with a 30-second rest period between each set. The first 2 weeks of training focused on core stabilization training, and the remaining 6 weeks of training focused primarily on core strengthening. Specifically, the first 2 weeks focused on controlling the contraction and relaxation of the core muscles with open kinetic exercises. We then gradually increased the intensity of the training with closed kinetic exercises, such as planks, in weeks 3–5. Finally, weeks 6–8 of the training program were used for more functional exercises, such as mini-squats, to engage and maximize the function of the involved core muscles. The intensity of the training was adjusted based on the Borg Category Ratio (CR)-10 scale. [25] The level of perceived exertion was gradually increased from “light” to “very hard” (Borg CR-10 scale “2” to “9”) over the 8-week intervention. The detailed physical training program is described in the table, Supplemental Digital Content http://links.lww.com/MD/I379. Participants were provided with adequate warm-up and cool-down periods before and after exercise. All training sessions were supervised and supervised by a professional athletic trainer.

For further reading, please download the study from here.