Effect of the Combination of Whole-Body Neuromuscular Electrical Stimulation and Voluntary Exercise on Metabolic Responses in Human

Impact of subtetanic neuromuscular electrical stimulation on cardiac autonomic nervous system in young individuals

BACKGROUND

Although subtetanic neuromuscular electrical stimulation (NMES) has been proposed as an exercise training and/or rehabilitation tool, the impact of NMES on the autonomic nervous system (ANS) is unclear. Thus, we hypothesized that NMES would alter ANS, i.e., increase sympathetic activity and decrease parasympathetic activity, in young individuals.

METHODS

Eighteen healthy young individuals (16 males, mean age: 22 [SD: 4] years, Body Mass Index: 21.7 [2.2] kg/m2) volunteered. Blood pressure (BP), heart rate (HR), and R-R intervals were recorded during 6-minute resting, NMES, and recovery conditions. Short-term heart rate variability analysis of R-R intervals was performed for the frequency and time domains during each condition. Time domain indices included the root mean square of successive R-R interval differences (RMSSD), and the percentage of successive R-R intervals differing by more than 50ms (pRR50%). Frequency domain indices (fast Fourier transform) of R-R intervals included total power (TP), low-frequency (LF) power (0.04-0.15 Hz), and high-frequency (HF) power (0.15-0.4 Hz).

RESULTS

BP was not altered but HR was significantly increased during NMES (P<0.001), and it returned to the resting level at recovery. RMSSD and pRR50 decreased from resting to NMES and returned at recovery conditions (P<0.05, respectively). TP and HF decreased from resting to NMES and returned at recovery conditions (P<0.05, respectively). LF increased from NMES to recovery (P<0.05). The LF/HF ratio showed no significant differences between conditions (P=0.210).

CONCLUSIONS

Cardiac ANS fluctuated by subtetanic NMES without BP elevation in healthy young individuals. Parasympathetic but not sympathetic activity was affected by NMES stimulation.

Whole-Body Electromyostimulation Impacts Physiological Responses During Aerobic Running: A Randomized Trial

Objective: The aim of the current study was to evaluate the physiological and metabolic responses to running with whole-body electromyostimulation (wbEMS) compared to running without electromyostimulation (control, CG). Methods: Twenty healthy participants (9 male/11 female, age 42 ±7 years) conducted an incremental step test with respiratory gas analysis until exhaustion. Trials were conducted as wbEMS and CG in a random order. As outcome measures, (A) objective total exhaustion, (B) athletic responses (max. time and velocity) and (C) physiological and metabolic responses (V'O2/ kg, V'E, EE, RER, lactate) were compared. (D) The impact on the skeletal muscle was assessed prior, 48 h & 72 h after trial. Results: During both trials, participants (A) ran until total exhaustion. Nonetheless, (B) time and velocity till exhaustion as well as (C) RER prior to the first lactate threshold and V'E were reduced with wbEMS. All other correlates did not differ significantly between wbEMS and CG. Following 48 h and 72 h after the trial with wbEMS, (D) the impact on the skeletal muscle was 7- to 9-fold higher compared to baseline values. Values differed significantly to those after running without wbEMS. Conclusion: With the additional stimulation during voluntary activation, wbEMS induces earlier fatigue and a shift in energy metabolism toward fat utilization. Even during aerobic endurance tasks, a great impact on the skeletal muscle indicated by the rise in CK could be observed which promotes wbEMS as an alternative training stimulus that is easy-to-apply and effective during endurance training.

Effects of neuromuscular electrical stimulation on glycemic control: a systematic review and meta-analysis

Background

Physical inactivity increases the risk for metabolic diseases such as obesity and type 2 diabetes. Neuromuscular electrical stimulation (NMES) is an effective method to induce muscle contraction, particularly for populations with physical impairments and/or metabolic diseases. However, its effectiveness to improve glycemic control is unclear. This review aimed to determine the effectiveness of NMES on glycemic control.

Methods

Electronic search consisted of MEDLINE (PubMed), EMBASE, Cochrane Library, Google Scholar, and Web of Science to identify studies that investigated the effects of NMES on glycemic control for this systematic review. The meta-analysis consists of the studies designed as randomized controlled trials. Effect sizes were calculated as the standardized mean difference (SMD) and meta-analysis was conducted using a random-effects model.

Results

Thirty-five studies met the inclusion criteria for systematic review and of those, nine qualified for the meta-analysis. Existing evidence suggested that NMES effectively improves glycemic control predominantly in middle-aged and elderly population with type 2 diabetes, obesity, and spinal cord injury. The meta-analysis is comprised of 180 participants and reported that NMES intervention lowered fasting blood glucose (SMD: 0.48; 95% CI: 0.17 to 0.78; p=0.002; I²=0%). Additional analysis using the primary measures reported by each study to indicate glycemic control (i.e., OGTT, HOMA-IR, and fasting glucose) also confirmed a significant effect of NMES on improving glycemic control (SMD: 0.41; 95% CI, 0.09 to 0.72; p=0.01; I²=11%). NMES protocol varied across studies and requires standardization.

Conclusion

NMES could be considered as a therapeutic strategy to improve glycemic control in populations with physical impairments and/or metabolic disorders.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42020192491.

Immediate Effects of Whole-Body versus Local Dynamic Electrostimulation of the Abdominal Muscles in Healthy People Assessed by Ultrasound: A Randomized Controlled Trial

Dynamic electrostimulation consists of the application of local or global electrostimulation together with physical exercise. This study aimed to investigate the immediate effects of a dynamic electrostimulation session on the thickness of the abdominal musculature, inter-rectus distance, heart rate, blood pressure, and body temperature, and to identify possible differences in its form of application. A total of 120 healthy participants were divided into three groups: the whole-body electrostimulation group, the local electrostimulation group, and the control group without electrical stimulation. All groups performed a single session with the same dynamic exercise protocol. Muscle thickness and inter-rectus distance were evaluated ultrasonographically using the Rehabilitative Ultrasound Imaging technique both at rest and in muscle contraction (the active straight leg raise test) to find the post-intervention differences. The results showed significant differences in immediate post-intervention heart rate, with a smaller increase in the local electrostimulation group compared to the control and whole-body electrostimulation groups. No significant differences were identified between the groups after the interventions in the rest of the variables analyzed. Therefore, a local application, with the same effects as a global application on the abdominal musculature, has fewer contraindications, which makes its use more advisable, especially in populations with cardiorespiratory disorders, for which more research is needed.

Effects of multicomponent exercise training on muscle oxygenation in young and older adults

Objective

Though multicomponent exercise training was found beneficial in improving the physical functionality, the effects of multicomponent exercise training on muscle oxygenation are still unclear. The purpose of this study was to investigate the effects of multicomponent exercise training on muscle oxygenation in young and older participants.

Methods

In this study, 17 young adults (Y) and 18 healthy older adults (E) were recruited to receive a multicomponent exercise training for 12 weeks, 2-3 sessions per week. Muscle oxygenation, muscle strength, and electromyography data were collected and compared pre- and post-training. Muscle oxygen saturation (SpO₂) during isometric knee extension tests involving voluntary contraction (VOL) and electrical stimulation (ES) was measured by near-infrared spectroscopy. The SpO₂ kinetics in the contraction and recovery phases were calculated using a tangential model to extract ΔSpO₂ and inflection time (IF).

Results

Muscle strength significantly increased in the post-training (234.31 ± 83.2 N·m, p < 0.05). The post-training ΔSpO₂ of the ES in the Y (8.43 ± 5.35%) significantly increased and was higher than that in the E (2.78 ± 3.03%, p < 0.05). In the recovery phase, the post-training IF of VOL (7.07 ± 3.31s) was significantly shorter than that of the pre-training period (8.73 ± 4.46s, p < 0.05). Additionally, the median frequency of electromyography significantly decreased in the post-training period (103.84 ± 21.75 Hz, p < 0.05).

Conclusion

The multicomponent exercise training improved the muscle strength, neuromuscular performance, and muscle aerobic function irrespective of age. The primary adaptation of the muscles to the multicomponent exercise training between the two groups varied.

Constant Load Pedaling Exercise Combined with Electrical Muscle Stimulation Leads to an Early Increase in Sweat Lactate Levels

A novel exercise modality combined with electrical muscle stimulation (EMS) has been reported to increase cardiovascular and metabolic responses, such as blood lactate concentration. We aimed to examine the effect of constant load pedaling exercise, combined with EMS, by non-invasively and continuously measuring sweat lactate levels. A total of 22 healthy young men (20.7 ± 0.8 years) performed a constant load pedaling exercise for 20 min at 125% of the pre-measured ventilatory work threshold with (EMS condition) and without (control condition) EMS stimulation. Blood lactate concentration was measured by blood samples obtained from the earlobe every minute. Sweat lactate was monitored in real time using a sensor placed on the forearm. The sweat lactate threshold (sLT) was defined as the point of increase in sweat lactate. sLT occurred significantly earlier in the EMS condition than in the control condition. In the single regression analysis, the difference in sLT between the two conditions, as the independent variable, was a significant predictor of the difference in blood lactate concentrations at the end of the exercise (p < 0.05, r = −0.52). Sweat lactate measurement may be a noninvasive and simple alternative to blood lactate measurement to determine the effectiveness of exercise combined with EMS.

Feasibility and Safety of Whole-Body Electromyostimulation in Frail Older People—A Pilot Trial

Whole-body electromyostimulation (WB-EMS) induces high-intense stimuli to skeletal muscles with low strain on joints and the autonomic nervous system and may thus be suitable for frail, older people. However, if trained at very high intensities, WB-EMS may damage muscles and kidneys (rhabdomyolysis). This study aimed at investigating the feasibility, safety and preliminary efficacy of WB-EMS in frail, older people. Seven frail (81.3 ± 3.5 years), 11 robust (79.5 ± 3.6 years), 10 young (29.1 ± 6.4 years) participants completed an eight-week WB-EMS training (week 1–4: 1x/week; week 5–8: 1.5x/week) consisting of functional exercises addressing lower extremity strength and balance. Feasibility was assessed using recruitment, adherence, retention, and dropout rates. The satisfaction with WB-EMS was measured using the Physical Activity Enjoyment Scale for older adults (PACES-8). In week 1, 3, and 8 creatine kinase (CK) was assessed immediately before, 48 and 72 h after WB-EMS. Symptoms of rhabdomyolysis (muscle pain, muscle weakness, myoglobinuria) and adverse events were recorded. Functional capacity was assessed at baseline and after 8 weeks using the Short Physical Performance Battery (SPPB), Timed Up-and-Go Test (TUG), Choice Stepping Reaction Time Test (CSRT), 30-second Chair-Stand Test (30-STS), maximum isometric leg strength and handgrip strength. The recruitment rate of frail individuals was 46.2%, adherence 88.3% and the dropout rate 16.7%. All groups indicated a high satisfaction with WB-EMS. CK activity was more pronounced in young individuals with significant changes over time. Within older people CK increased borderline-significantly in the frail group from baseline to week 1 but not afterwards. In robust individuals CK increased significantly from baseline to week 1 and 3. No participant reached CK elevations close to the threshold of ≥5,000 U/l and no symptoms of rhabdomyolysis were observed. With the exception of the TUG (p = 0.173), frail individuals improved in all tests of functional capacity. Compared to the young and robust groups, frail individuals showed the greater improvements in the SPPB, handgrip strength, maximum isokinetic hip-/knee extension and flexion strength. WB-EMS is feasible for frail older people. There were no clinical signs of exertional rhabdomyolysis. WB-EMS proved to be sufficiently intense to induce meaningful changes in functional capacity with frail individuals showing greater improvements for several measures.

Acute Effect of Electromyostimulation Superimposed on Running on Maximal Velocity, Metabolism, and Perceived Exertion

Electromyostimulation has been shown to intensify exercise when superimposed on cycling. However, little is known about the application during running, which might help to prevent injuries linked to high running volumes, as intensification of running allows for a reduction in training volume. Therefore, the purpose of the study was to examine the effects of electromyostimulation superimposed on running. Men who were no younger than 18 and no older than 35 were eligible for inclusion in the study. Exclusion criteria were previous experience with electromyostimulation training, the presence of a contraindication according to the manufacturer, or a contraindication to physical activity. A sample of 22 healthy males with an ordinary performance capability accomplished three similar cardiopulmonary treadmill tests until exhaustion in a crossover study design that included lactate measurements and interrogations of perceived exertion. The first test was conducted without electromyostimulation and was followed in a randomized order by the second and the third test condition with 30 or 85 Hz stimulation, respectively, of the lower body. Superimposed electromyostimulation significantly reduced the maximal achieved velocity (control 15.6 ± 1.1 vs. 30 Hz 15.1 ± 1.2, p = 0.002; vs. 85 Hz 14.9 ± 1.1 km/h, p < 0.001), increased the perceived exertion at 10, 12 and 14 km/h (85 Hz + 0.7, p = 0.036; +0.9, p = 0.007; +1.3, p < 0.001; 30 Hz + 0.7, p = 0.025; +1.0, p = 0.002; +1.2, p < 0.001), and induced a significantly higher oxygen uptake at 8 km/h (85 Hz + 1.1, p = 0.006; 30 Hz + 0.9 mL·min−1·kg−1, p = 0.042), 10 km/h (30 Hz + 0.9 mL·min−1·kg−1, p = 0.032), and 14 km/h (85 Hz + 1.0 mL·min−1·kg−1, p = 0.011). Both electromyostimulation conditions significantly limited the maximal lactate level (30 Hz p = 0.046; 85 Hz p < 0.001) and 85 Hz also the recovery lactate level (p < 0.001). Superimposed electromyostimulation is feasible and intensifies running. Coaches and athletes could benefit from the increased training stimulus by reducing running velocity or volume, by combining endurance and strength training, and also by inducing better adaptations while maintaining the same velocity or volume. Therefore, electromyostimulation superimposed on running could be an interesting training tool for runners.

Profile of Whole Body Electromyostimulation Training Users-A Pilot Study

(1) Introduction: Whole Body Electromyostimulation is a technological and time efficient personal training practiced all over the world. With the increase of practitioners in the last 10 years, the need to study more about practitioners has arisen, so this pilot study aims to trace a user profile of this method through the analysis of socio-demographic data for a better understand of the profile of people looking for this type of training to improve the effectiveness of the intervention and develop programs that are in accordance with the motivation of practitioners. (2) Methods: 270 users from 5 countries answered an online questionnaire with socio-demographic questions. Data were treated using descriptive statistics. Possible differences between sexes and between groups were analyzed by means of non-parametric statistical tests: Mann−Whitney U-test (continuous variables); in addition to studying possible dependence relationships and differences between proportions, using the Chi-square statistic with pairwise z-test using the Bonferroni correction (categorical variables). (3) Results: Middle-aged women are the main user of this type of training. The majority of WB-EMS users do another type of physical activity with significant difference between men and woman (p < 0.05) men are more active than women. Weight loss, health and wellness and muscle mass increase are the main goals of the WB-EMS users. There are significant differences in weight loss and rehabilitation between genders (p < 0.05). Women look much more than men to lose weight and men look more than women to rehabilitation. (4) Conclusions: The user profile is a physically active woman, aged 35−49 years, with normal weight and high educational level, who carries out twice weekly full body electrostimulation training with the goals of weight loss, health and/or wellness and muscle mass gain.

Whole-Body EMS Superimposed Walking and Nordic Walking on a Treadmill-Determination of Exercise Intensity to Conventional Exercise

Electrical muscle stimulation (EMS) is an increasingly popular training method and has become the focus of research in recent years. New EMS devices offer a wide range of mobile applications for whole-body EMS (WB-EMS) training, e.g., the intensification of dynamic low-intensity endurance exercises through WB-EMS. The present study aimed to determine the differences in exercise intensity between WB-EMS-superimposed and conventional walking (EMS-CW), and CON and WB-EMS-superimposed Nordic walking (WB-EMS-NW) during a treadmill test. Eleven participants (52.0 ± years; 85.9 ± 7.4 kg, 182 ± 6 cm, BMI 25.9 ± 2.2 kg/m²) performed a 10 min treadmill test at a given velocity (6.5 km/h) in four different test situations, walking (W) and Nordic walking (NW) in both conventional and WB-EMS superimposed. Oxygen uptake in absolute (VO₂) and relative to body weight (rel. VO₂), lactate, and the rate of perceived exertion (RPE) were measured before and after the test. WB-EMS intensity was adjusted individually according to the feedback of the participant. The descriptive statistics were given in mean ± SD. For the statistical analyses, one-factorial ANOVA for repeated measures and two-factorial ANOVA [factors include EMS, W/NW, and factor combination (EMS^*W/NW)] were performed (α = 0.05). Significant effects were found for EMS and W/NW factors for the outcome variables VO₂ (EMS: p = 0.006, r = 0.736; W/NW: p < 0.001, r = 0.870), relative VO₂ (EMS: p < 0.001, r = 0.850; W/NW: p < 0.001, r = 0.937), and lactate (EMS: p = 0.003, r = 0.771; w/NW: p = 0.003, r = 0.764) and both the factors produced higher results. However, the difference in VO₂ and relative VO₂ is within the range of biological variability of ± 12%. The factor combination EMS^*W/NW is statistically non-significant for all three variables. WB-EMS resulted in the higher RPE values (p = 0.035, r = 0.613), RPE differences for W/NW and EMS^*W/NW were not significant. The current study results indicate that WB-EMS influences the parameters of exercise intensity. The impact on exercise intensity and the clinical relevance of WB-EMS-superimposed walking (WB-EMS-W) exercise is questionable because of the marginal differences in the outcome variables.

Electrical-tomographic imaging of physiological-induced conductive response in calf muscle compartments during voltage intensity change of electrical muscle stimulation (vic-EMS)

Objectives. The electrical-tomographic imaging has been achieved for exploring differential tendency of physiological-induced conductive response in calf muscle compartments during voltage intensity change of electrical muscle stimulation (vic-EMS).Approach. In the experiments, the differential tendency of conductivity distribution imagesσduringvic-EMS were clearly imaged as three responsive muscle compartments, which are calledM₁compartment composed of gastrocnemius muscle,M₂compartment composed of tibialis anterior, extensor digitorum longus, and peroneus longus muscles, andM₃compartment composed of soleus muscle.Main results. The differential tendency of spatial-mean conductivity 〈σ〉_M1is the same as the differential tendency of venous blood flow velocityv_bland blood lactate concentrationC_blduringvic-EMS by the increased tendency of spatial-mean conductivity difference Δ〈σ〉_M1, venous blood flow velocity difference Δv_bland blood lactate concentration difference ΔC_bl. The 〈σ〉_M1is increased with the increase of voltage intensity from 〈σ^pre〉_M1 = 0.142 [-] to 〈σ^l14 〉 _M1 = 0.442 [-] (pre: pre-training,l14: voltage level duringvic-EMSl = 14) by Δ〈σ^l14-pre〉_M1 = 204.2% (n = 16,p < 0.01). Correspondingly, thev_blandC_blare increased with the increase of voltage intensity by Δv_bl^l14-pre= 1480.5% (n = 16,p < 0.01) and ΔC_bl^l14-pre= 230.1% (n = 16,p < 0.01) respectively.Significance: The reason for the differential tendency of increase in <σ>_M1suggests an increase in muscle extracellular volumes duringvic-EMS due to the co-effect of venous blood flow velocity and blood lactate metabolism. Based on the conductivity second-order difference images∂2σM1φ∂φ2φand spatial-mean conductivity second-order difference∂2σM1φ∂φ2φ,optimum voltage intensityφ_OVIis discussed among sixteen volunteer subjects, which increased with a thicker subcutaneous fat layer.

Effects of whole-body neuromuscular electrical stimulation device on hemodynamics, arrhythmia, and sublingual microcirculation

Neuromuscular electrical stimulation has been used to treat cardiovascular diseases and other types of muscular dysfunction. A novel whole-body neuromuscular electrical stimulation (WB-NMES) wearable device may be beneficial when combined with voluntary exercises. This study aimed to investigate the safety and effects of the WB-NMES on hemodynamics, arrhythmia, and sublingual microcirculation. The study included 19 healthy Japanese volunteers, aged 22-33 years, who were not using any medication. Electrocardiogram (ECG), echocardiography, and blood sampling were conducted before a 20-min WB-NMES session and at 0 and 10 min after termination of WB-NMES. Their tolerable maximum intensity was recorded using numeric rating scale. Arrhythmia was not detected during neuromuscular electrical stimulation or during 10 min of recovery. Blood pressure, heart rate, left ventricular ejection fraction, and diastolic function remained unchanged; however, mild mitral regurgitation was transiently observed during WB-NMES in a single male participant. A decrease in blood glucose and an increase in blood lactate levels were observed, but no changes in blood fluidity, sublingual microcirculation, blood levels of noradrenaline, or oxidative stress were shown. WB-NMES is safe and effective for decreasing blood glucose and increasing blood lactate levels without changing the blood fluidity or microcirculation in healthy people.

A Single Session of Whole-Body Electromyostimulation Increases Muscle Strength, Endurance and proNGF in Early Parkinson Patients

Parkinson's disease (PD) patients lead a sedentary lifestyle, being unable or unwilling to exercise conventionally, due to physical and mental limitations. The aim of this study was to assess the acute effects of a single session of whole-body electromyostimulation (WB-EMS) on the physical performances and serum levels of the neurotrophic factors in PD patients. Ten subjects (aged 72.60 ± 6.82) underwent 20 min of physical activity with superimposed WB-EMS and, after four weeks, the same protocol with no WB-EMS. WB-EMS was conducted with intermittent stimulation, with 4 s WB-EMS/4 s rest, at 85 Hz, 350 μs. A physical fitness assessment and blood samples collection, to evaluate neurotrophic factors' levels (BDNF, FGF21, proNGF, mNGF), were collected before and after the intervention. The RM-ANOVA showed significant improvements in sit-to-stand (p < 0.01), arm curl (p < 0.01), handgrip (p < 0.01) and soda pop test (p < 0.01) after the WB-EMS intervention. Higher proNFG serum levels were observed in the WB-EMS condition compared to the no WB-EMS after 60 min post-intervention (p = 0.0163). The effect of WB-EMS confirmed the electrostimulation ability to modulate the proNGF quantity. The positive impact of the WB-EMS protocol on physical functioning, and eye-hand coordination, makes this intervention a promising strategy to improve motor and non-motor symptoms in PD patients.

The effects of whole-body muscle stimulation on body composition and strength parameters: A protocol for systematic review and meta-analysis

BACKGROUND

This study will analyze the effect of Whole Body Electromyostimulation (WB-EMS) in strength and body composition outcomes in adult population.

METHODS

This study will search the following electronic databases up to July 21, 2020: PubMed, WOS, Scopus, SPORTDiscus y EMBASE. There will be no language limitation. Two authors will independently identify titles/abstracts and full text all potential studies, and will collect data from eligible studies. Additionally, study quality will be assessed by PEDro Scale risk of bias. We will conduct meta-analysis if enough trials are included.

RESULTS

This study will explore the effects of WB-EMS in strength and body composition outcomes.

CONCLUSION

The findings of this study may summarize the effectiveness of WB-EMS in increasing strength and improving body composition in adult population.

INPLASY REGISTRATION NUMBER

INPLASY202120050.

Acute effects of repetitive peripheral magnetic stimulation following low-intensity isometric exercise on muscle swelling for selective muscle in healthy young men

Repetitive peripheral magnetic stimulation (rPMS) is a non-invasive stimulator that can induce strong muscle contraction in selective regions. This study aimed to measure acute changes in skeletal muscle thickness induced by rPMS following a low-intensity exercise. Fifteen healthy young men performed an isometric knee extensor exercise at 30% of maximum strength consisting of three sets of 10 contractions on their dominant leg. rPMS was then applied on the vastus lateralis (VL) at the maximum intensity of the rPMS device. Muscle thicknesses of the rectus femoris (RF) and VL were measured using an ultrasound device and were compared among baseline, post-exercise, and post-rPMS. There were significant increases in muscle thickness of both the RF and VL post-exercise compared with baseline values (RF: baseline; 24.7 ± 2.4, post-exercise; 25.3 ± 2.4 mm, p = .034, VL: baseline; 27.0 ± 2.8, post-exercise; 27.4 ± 2.8 mm, p = .006). Compared with post-exercise, there was a significant increase post-rPMS in only the VL (VL: post-rPMS; 28.3 ± 2.9 mm, p = .002). These findings suggest that low-intensity isometric exercise can induce acute increases in muscle thickness (muscle swelling) in synergist muscles, and rPMS following exercise can induce further acute muscle swelling via repetitive muscle contraction.

Higher Impulse Electromyostimulation Contributes to Psychological Satisfaction and Physical Development in Healthy Men

Background and Objectives: This study investigated the various impulse effects of whole-body electromyostimulation (WB-EMS) on psychophysiological responses and adaptations. Materials and Methods: The participants included fifty-four men between 20 and 27 years of age who practiced isometric exercises for 20 min, three days a week, for 12 weeks while wearing WB-EMS suits, which enabled the simultaneous activation of eight muscle groups with three types of impulse intensities. Participants were allocated to one of four groups: control group (CON), low-impulse-intensity group (LIG), mid-impulse-intensity group (MIG), and high-impulse-intensity group (HIG). Psychophysiological conditions were measured at week 0, week 4, week 8, and week 12. Results: Compared with the CON, (1) three psychological conditions in LIG, MIG, and HIG showed positive tendencies every four weeks, and the analysis of covariance (ANCOVA) test revealed that body image (p = 0.004), body shape (p = 0.007), and self-esteem (p = 0.001) were significantly different among the groups. (2) Body weight, fat mass, body mass index, and percent fat in the CON showed decreasing tendencies, whereas those in LIG, MIG, and HIG showed a noticeable decrease, which revealed that there were significant differences among the groups. Specifically, a higher impulse intensity resulted in a greater increase in muscle mass. (3) Although there was no interaction effect in the abdominal visceral fat area, there were significant interactions in the abdominal subcutaneous fat (ASF) and total fat (ATF) areas. Both the ASF and ATF in the CON showed decreasing tendencies, whereas those in other groups showed a noticeable decrease. The ANCOVA revealed that the ASF (p = 0.002) and ATF (p = 0.001) were significantly different among the groups. In particular, the higher the impulse intensity, the greater the decrease in abdominal fat. Conclusions: This study confirmed that high-impulse-intensity EMS can improve psychophysiological conditions. In other words, healthy young adults felt that the extent to which their body image, body shape, and self-esteem improved depended on how intense their EMS impulse intensities were. The results also showed that higher levels of impulse intensity led to improved physical conditions.

Effect of exercise intensity on metabolic responses on combined application of electrical stimulation and voluntary exercise

The combined application of voluntary exercises and neuromuscular electrical stimulation (NMES) has been developed as a new type of exercise that can recruit motor units contributing to both aerobic and anaerobic energy metabolisms. We aimed to investigate the effect of voluntary exercise intensity on metabolic responses on the combination of voluntary exercise and NMES. In 13 volunteers, oxygen consumption and the blood lactate concentration were measured during (1) voluntary pedaling exercise at four different intensities: 50%, 75%, 100%, and 125% of the ventilatory threshold (VT) (VOL), (2) these voluntary exercises with superimposed NMES applied to the gluteus and thigh muscles (VOL+NMES), and (3) NMES only (NMES). Oxygen consumption and the blood lactate concentration in VOL+NMES were significantly greater than VOL at each exercise intensity (p < 0.05). Differences in oxygen consumption between VOL+NMES and VOL decreased with exercise intensity, and that at 125% VT was significantly lower than the net gain in oxygen consumption following NMES (p < 0.05). Differences in the blood lactate concentration between VOL+NMES and VOL increased with exercise intensity, and that at 50% VT was significantly lower than the net gain in the blood lactate concentration following NMES (p < 0.05). Our results suggest that voluntary exercise intensity has a critical impact on metabolic responses during the combined application of voluntary exercises and NMES. Superimposing NMES onto voluntary exercises at high exercise intensities may induce overlapping recruitment of motor units, leading to a markedly reduced benefit of additional metabolic responses on its superimposition.