Body Composition, and What Does The Research Say

WB-EMS vs. Traditional Resistance Training

One of the most relevant studies directly compared WB-EMS with high-intensity resistance training (not to be confused with HIIT, which stands for high-intensity interval training). Kemmler et al. (2016) randomly assigned 48 healthy, previously untrained men between 30 and 50 years old to either high-intensity resistance training or WB-EMS.

The resistance-training group was prescribed two sessions per week for 16 weeks using a single-set-to-failure protocol involving 10–13 exercises targeting the major muscle groups. The WB-EMS group trained three times every two weeks, with each session lasting 20 minutes. EMS was delivered at 85 Hz with a 350 μs pulse width using six seconds of stimulation followed by four seconds of rest. Participants performed low-amplitude movements such as squats, deadlifts, crunches, and rowing movements during stimulation.

The time difference is important. The WB-EMS sessions lasted 20 minutes, while the resistance-training sessions were approximately 30 minutes based on the study's reported training time. The resistance-training protocol therefore required roughly 50% more time per session. Despite that difference, both groups experienced significant increases in lean body mass: 1.25% with resistance training versus 0.93% with WB-EMS. The difference between groups was not statistically significant.

This does not mean that 20 minutes of EMS is universally equivalent to 30 minutes of resistance training. The protocols were different, and the study involved previously untrained middle-aged men. However, it does provide evidence that a substantially shorter WB-EMS protocol can produce similar changes in lean body mass to a high-intensity resistance-training program in this population (Kemmler et al., 2016).

Can EMS Help Preserve Muscle During Weight Loss?

Maintaining muscle becomes particularly important when someone is intentionally losing weight. A calorie deficit can reduce body fat, but it can also result in the loss of lean tissue.

Willert et al. (2019) studied 90 overweight premenopausal women between 25 and 50 years old over 16 weeks. Participants were divided into three groups.

The first group created an approximately 500-calorie-per-day deficit through dietary restriction. The second group created the deficit through a combination of dietary restriction and increased physical activity. The third group followed the same dietary and physical-activity approach while also performing WB-EMS.

The WB-EMS group performed 20-minute sessions 1.5 times per week on average, using 85 Hz, 350 μs and six seconds of stimulation followed by four seconds of rest. The physical-activity group, however, did not perform a standardized exercise session of a fixed duration; instead, participants were instructed to increase daily physical activity sufficiently to create approximately 250 additional calories of expenditure per day.

All three groups significantly reduced body fat. Fat mass decreased by approximately 2.17 kg in the diet-only group, 3.74 kg in the physical-activity group, and 3.28 kg in the WB-EMS group. The differences between groups were not statistically significant.

The lean-mass findings were particularly interesting. Lean body mass decreased in the diet-only and physical-activity groups but increased in the WB-EMS group. The overall between-group comparison did not reach statistical significance, although the adjusted pairwise comparison between WB-EMS and the physical-activity group was significant (Willert et al., 2019).

The study therefore provides interesting evidence that WB-EMS may help preserve lean mass during an energy deficit, but it does not demonstrate that EMS produces greater fat loss than diet or increased physical activity.

What About Older Adults?

Some of the most interesting body-composition research has been conducted in older adults, where maintaining muscle mass becomes increasingly important.

In the TEST-III randomized controlled trial, Kemmler et al. (2014) studied 76 lean, sedentary women averaging approximately 75 years old. The WB-EMS group performed 18-minute sessions three times every 14 days, or approximately 1.5 sessions per week, for 54 weeks. The stimulation was delivered at 85 Hz while participants performed low-intensity movements.

The control group was intentionally active rather than completely sedentary. Participants performed the same general low-intensity movements without electrical stimulation in two supervised blocks of training, with each control session lasting 60 minutes once per week, making the control sessions more than three times longer.

After 54 weeks, skeletal muscle mass increased 0.4% with WB-EMS while decreasing 1.5% in the control group. Lean body mass increased 0.8% with WB-EMS and decreased 0.8% in the control group. Differences in overall body-fat measures did not reach statistical significance (Kemmler et al., 2014).

A related analysis of 46 women from the TEST-III population specifically examined abdominal fat and muscle mass. Kemmler and von Stengel (2013) reported that the WB-EMS group increased appendicular muscle mass by 0.5%, compared with a 0.8% decrease in the active control group. Abdominal fat mass decreased 1.2% with WB-EMS while increasing 2.4% in the control group.

WB-EMS and Sarcopenic Obesity

The FORMOsA study (Kemmler et al., 2016) examined 75 community-dwelling women aged 70 and older with sarcopenic obesity. Participants were assigned to WB-EMS, WB-EMS combined with protein supplementation, or a non-training control group.

The EMS groups performed one 20-minute session per week using 85 Hz, 350 μs and four seconds of stimulation followed by four seconds of rest. The study lasted six months.

The results were particularly notable for muscle mass. Skeletal muscle mass index increased approximately 2.0–2.5% in the two WB-EMS groups, while it decreased approximately 1.2% in the control group. Fat mass also decreased in the EMS groups, but the difference compared with the control group was not statistically significant.

The authors characterized the effect on muscle mass as substantial and the effect on fat mass as comparatively minor.

What If You Only Do EMS Once a Week?

A randomized controlled study by Kemmler et al. (2021) examined 54 male amateur golfers between 18 and 70 years old. The WB-EMS group performed one 20-minute session per week for 16 weeks, using 85 Hz, 350 μs, and intermittent stimulation combined with low-intensity movements. The control group simply maintained its habitual physical activity.

After 16 weeks, the WB-EMS group demonstrated a significant between-group effect for lean body mass. However, body-fat content did not differ significantly between groups.

This study is useful because it represents a minimal baseline. It provides additional evidence that even a relatively small weekly training commitment can produce measurable changes in lean body mass, although it did not demonstrate a significant reduction in body fat.

What Does the Overall Research Show?

The broader research generally supports the potential of WB-EMS to improve muscle-related body-composition outcomes.

A 2021 systematic review and meta-analysis by Kemmler et al. examined 16 studies involving 897 participants. The researchers found large and statistically significant effects for muscle mass, leg strength, and trunk strength. However, the overall effect on body fat did not reach statistical significance.

A later 2023 systematic review and meta-analysis included 26 studies involving 1,183 participants. This analysis reported statistically significant effects for muscle mass, body fat, strength, and power, although the researchers noted moderate heterogeneity for body-fat and strength outcomes (Kemmler et al., 2023).

Taken together, the research suggests that WB-EMS can contribute to meaningful improvements in body composition, particularly lean body mass and muscle preservation. Evidence for fat loss is more variable and appears to depend heavily on the broader intervention, including nutrition, energy balance, physical activity, and the characteristics of the individual.

Time Efficiency

Perhaps one of the most interesting aspects of the research is not simply whether EMS works, but how much training time may be required to produce meaningful results.

Several controlled studies have reported improvements in lean mass with WB-EMS sessions lasting only 18–20 minutes, often performed once or 1.5 times per week. In some studies, those results were comparable to those produced by substantially longer traditional exercise protocols.

This does not mean that 20 minutes of EMS is universally equivalent to a longer resistance-training program. Traditional resistance training has an extensive evidence base, and the EMS studies use different populations, protocols, and outcome measures.

But the time-efficiency question is compelling.

For people who struggle to find time for exercise, the ability to provide a substantial muscular stimulus in a short session represents a potentially important advantage. The research suggests that WB-EMS can produce measurable changes in lean mass with a relatively small time commitment.

And this leads to perhaps the most interesting question for future research: What happens when EMS is combined with traditional resistance training?

Traditional resistance training provides mechanical loading, while EMS provides an additional electrical stimulus to the muscles. Combining the two could potentially bring together the strengths of both approaches.

The question is worth investigating.

References

• Kemmler, W., Teschler, M., Weißenfels, A., Bebenek, M., Fröhlich, M., Kohl, M., & von Stengel, S. (2016). Effects of whole-body electromyostimulation versus high-intensity resistance exercise on body composition and strength: A randomized controlled study. Evidence-Based Complementary and Alternative Medicine, 2016, 9236809.
• Willert, S., Weissenfels, A., Kohl, M., von Stengel, S., Fröhlich, M., Kleinöder, H., Schöne, D., Teschler, M., & Kemmler, W. (2019). Effects of whole-body electromyostimulation on the energy-restriction-induced reduction of muscle mass during intended weight loss. Frontiers in Physiology, 10, 1012.
• Kemmler, W., Bebenek, M., Engelke, K., & von Stengel, S. (2014). Impact of whole-body electromyostimulation on body composition in elderly women at risk for sarcopenia: The Training and ElectroStimulation Trial (TEST-III). Age, 36, 395–406.
• Kemmler, W., & von Stengel, S. (2013). Whole-body electromyostimulation as a means to impact muscle mass and abdominal body fat in lean, sedentary, older female adults: Subanalysis of the TEST-III trial. Clinical Interventions in Aging, 8, 1353–1361.
• Kemmler, W., Teschler, M., Weissenfels, A., Bebenek, M., Fröhlich, M., Kohl, M., & colleagues. (2016). Whole-body electromyostimulation to fight sarcopenic obesity in community-dwelling older women at risk: Results of the randomized controlled FORMOsA-sarcopenic obesity study. Osteoporosis International, 27, 3261–3270.
• Kemmler, W., et al. (2021). Once-weekly whole-body electromyostimulation increases strength, stability and body composition in amateur golfers: A randomized controlled study. International Journal of Environmental Research and Public Health, 18(11), 5628.
• Kemmler, W., Shojaa, M., Steele, J., Berger, J., Fröhlich, M., Schoene, D., von Stengel, S., Kleinöder, H., & Kohl, M. (2021). Efficacy of whole-body electromyostimulation (WB-EMS) on body composition and muscle strength in non-athletic adults: A systematic review and meta-analysis. Frontiers in Physiology, 12, 640657.
• Kemmler, W., et al. (2023). The effects of whole-body muscle stimulation on body composition and strength parameters: A PRISMA systematic review and meta-analysis.

About the Author

Conrad Sanchez is a leading Whole-Body EMS (WB-EMS) educator and expert with over a decade of experience in the industry. He holds a Master’s degree in Kinesiology and specialized certifications from the world’s top EMS manufacturers. When he isn't staying current on the latest WB-EMS research, you can find him helping the next generation of BODY20 members reach their peak potential.

Stay tuned for more deep dives into the science of EMS fitness.