Abstract
Electromyostimulation (EMS) is characterized as an electrical stimulation of superficial skeletal muscles so that visible muscle contractions are elicited. Voluntary contractions are not required but can be performed simultaneously. EMS is used as a training tool to stimulate immobilized muscles in patients who are unable to perform voluntary contractions or to intensify the training in healthy populations. While a large body of research already exists on local EMS stimulation, evidence regarding whole-body EMS (WB-EMS) in both athletic and clinical populations is inconclusive due to a lack of existing studies. Therefore, this dissertation includes two randomized controlled intervention studies with the training method WB-EMS and different populations as well as a network meta-analysis on the effects of local and WB-EMS in athletes.
The aim of the first intervention study was to assess the effects of an eight-week, dynamic, superimposed, submaximal WB-EMS training on maximal strength and power parameters of the leg muscles compared with a similar dynamic training without WB-EMS. For this purpose, 18 male subjects were allocated to two different study arms (WB-EMS vs. Control) in a randomized controlled trial design. Significant time effects were found for both strength and power parameters of leg extension (LE Fmax +5%; 0.24 ηp²) as well as leg curl (LC Pmax +13.5%; 0.35 ηp²). A significant interaction effect was merely observed for knee extension Fmax (0.21 ηp²), with the WB-EMS group showing greater strength gains (WB-EMS: +7.7%, SMD 0.61; Control: +2.1%, SMD 0.17). The results show that dynamic, submaximal stimulation with WB-EMS is suitable to induce improvements in strength and performance parameters. Nevertheless, the results of this study also suggest that the improvements obtained in young male athletes are comparable to those obtained with dynamic strength training without WB-EMS.
The second randomized and controlled intervention study examined the effects of a twelve-week WB-EMS training in patients with chronic non-specific back pain on pain symptoms and trunk strength compared to established training methods like whole-body vibration (WBV) and classic strength training for the back (CT). For this purpose, 240 patients were distributed among three study arms (WB-EMS vs. WBV vs. CT). All three training methods led to significant reductions in back pain (WB-EMS: 29.7 ± 39.1% (SMD 0.50) vs. WBV: 30.3 ± 39.3% (SMD 0.57) vs. CT: 30.5 ± 39.6% (SMD 0.59)) and improvements in trunk strength. No interaction effects were found for the respective groups. Accordingly, WB-EMS, WBV, and CT are comparably effective in relieving back pain and increasing trunk strength in patients with chronic non-specific low back pain. Nevertheless, it should be noted that the training effects with WB-EMS were achieved in an overall shorter training time.
For the third study, a network meta-analysis (NMA) was created to evaluate the effectiveness of different EMS interventions on performance parameters in athletes. For this purpose, a systematic literature research was conducted. In total, the results of 36 different studies with 1,092 subjects were included in the analysis. Four networks on the outcome parameters of maximum strength, jumping performance, sprint performance and aerobic capacity could be built and a ranking of the different exercise methods was achieved. The largest effects were found for a combination of strength training with superimposed EMS and additional jump training (strength outcome: SMD 4.43; jump outcome: SMD 3.14). The results of this NMA suggest that the choice of EMS-specific factors, such as the mode of application, the combination with voluntary muscle activation and the choice of the stimulation protocol, have an influence on training effectiveness. In particular, a high stimulation intensity, a relatively low EMS volume, and outcome-specific movement patterns appear to positively influence adaptations.
The aim of the first intervention study was to assess the effects of an eight-week, dynamic, superimposed, submaximal WB-EMS training on maximal strength and power parameters of the leg muscles compared with a similar dynamic training without WB-EMS. For this purpose, 18 male subjects were allocated to two different study arms (WB-EMS vs. Control) in a randomized controlled trial design. Significant time effects were found for both strength and power parameters of leg extension (LE Fmax +5%; 0.24 ηp²) as well as leg curl (LC Pmax +13.5%; 0.35 ηp²). A significant interaction effect was merely observed for knee extension Fmax (0.21 ηp²), with the WB-EMS group showing greater strength gains (WB-EMS: +7.7%, SMD 0.61; Control: +2.1%, SMD 0.17). The results show that dynamic, submaximal stimulation with WB-EMS is suitable to induce improvements in strength and performance parameters. Nevertheless, the results of this study also suggest that the improvements obtained in young male athletes are comparable to those obtained with dynamic strength training without WB-EMS.
The second randomized and controlled intervention study examined the effects of a twelve-week WB-EMS training in patients with chronic non-specific back pain on pain symptoms and trunk strength compared to established training methods like whole-body vibration (WBV) and classic strength training for the back (CT). For this purpose, 240 patients were distributed among three study arms (WB-EMS vs. WBV vs. CT). All three training methods led to significant reductions in back pain (WB-EMS: 29.7 ± 39.1% (SMD 0.50) vs. WBV: 30.3 ± 39.3% (SMD 0.57) vs. CT: 30.5 ± 39.6% (SMD 0.59)) and improvements in trunk strength. No interaction effects were found for the respective groups. Accordingly, WB-EMS, WBV, and CT are comparably effective in relieving back pain and increasing trunk strength in patients with chronic non-specific low back pain. Nevertheless, it should be noted that the training effects with WB-EMS were achieved in an overall shorter training time.
For the third study, a network meta-analysis (NMA) was created to evaluate the effectiveness of different EMS interventions on performance parameters in athletes. For this purpose, a systematic literature research was conducted. In total, the results of 36 different studies with 1,092 subjects were included in the analysis. Four networks on the outcome parameters of maximum strength, jumping performance, sprint performance and aerobic capacity could be built and a ranking of the different exercise methods was achieved. The largest effects were found for a combination of strength training with superimposed EMS and additional jump training (strength outcome: SMD 4.43; jump outcome: SMD 3.14). The results of this NMA suggest that the choice of EMS-specific factors, such as the mode of application, the combination with voluntary muscle activation and the choice of the stimulation protocol, have an influence on training effectiveness. In particular, a high stimulation intensity, a relatively low EMS volume, and outcome-specific movement patterns appear to positively influence adaptations.
| Translated title of the contribution | Applicability & effects of whole body-electromyostimulation in athletic, healthy & clinical populations |
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| Original language | German |
| Place of Publication | Köln |
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| Publisher | Deutsche Sporthochschule Köln |
| Number of pages | 57 |
| Publication status | Published - 15.05.2023 |