Electrical stimulation of human lower extremities enhances energy consumption, carbohydrate oxidation, and whole body glucose uptake

Combined effects of electrical muscle stimulation and cycling exercise on cognitive performance

The purpose of this study was to investigate whether a combination of electrical muscle stimulation (EMS) and cycling exercise is beneficial for improving cognitive performance. Eighteen participants (7 females and 11 males) performed a Go/No-Go task before and 2 min after i) cycling exercise (EX), ii) a combination of EMS and cycling (EMS + EX) and iii) a control (rest) intervention in a randomized controlled crossover design. In the EX intervention, the participants cycled an ergometer for 20 min with their heart rate maintained at ∼120 beats·min-1. In the EMS + EX intervention, the participants cycled an ergometer simultaneously with EMS for 20 min, with heart rate maintained at ∼120 beats·min-1. In the Control intervention, the participants remained at rest while seated on the ergometer. Cognitive performance was assessed by reaction time (RT) and accuracy. There was a significant interaction between intervention and time (p = 0.007). RT was reduced in the EX intervention (p = 0.054, matched rank biserial correlation coefficient = 0.520). In the EMS + EX intervention, RT was not altered (p = 0.243, Cohen's d = 0.285) despite no differences in heart rate between the EX and EMS + EX interventions (p = 0.551). RT was increased in the Control intervention (p = 0.038, Cohen's d = -0.529). These results indicate that combining EMS and cycling does not alter cognitive performance despite elevated heart rate, equivalent to a moderate intensity. The present findings suggest that brain activity during EMS with cycling exercise may be insufficient to improve cognitive performance when compared to exercise alone.

Differential changes in blood flow and oxygen utilization in active muscles between voluntary exercise and electrical muscle stimulation in young adults

The physiological effects on blood flow and oxygen utilization in active muscles during and after involuntary contraction triggered by electrical muscle stimulation (EMS) remain unclear, particularly compared with those elicited by voluntary (VOL) contractions. Therefore, we used diffuse correlation and near-infrared spectroscopy (DCS-NIRS) to compare changes in local muscle blood flow and oxygen consumption during and after these two types of muscle contractions in humans. Overall, 24 healthy young adults participated in the study, and data were successfully obtained from 17 of them. Intermittent (2-s contraction, 2-s relaxation) isometric ankle dorsiflexion with a target tension of 20% of maximal VOL contraction was performed by EMS or VOL for 2 min, followed by a 6-min recovery period. DCS-NIRS probes were placed on the tibialis anterior muscle, and relative changes in local tissue blood flow index (rBFI), oxygen extraction fraction (rOEF), and metabolic rate of oxygen (rMRO2) were continuously derived. EMS induced more significant increases in rOEF and rMRO2 than VOL exercise but a comparable increase in rBFI. After EMS, rBFI and rMRO2 decreased more slowly than after VOL and remained significantly higher until the end of the recovery period. We concluded that EMS augments oxygen consumption in contracting muscles by enhancing oxygen extraction while increasing oxygen delivery at a rate similar to the VOL exercise. Under the conditions examined in this study, EMS demonstrated a more pronounced and/or prolonged enhancement in local muscle perfusion and aerobic metabolism compared with VOL exercise in healthy participants.NEW & NOTEWORTHY This is the first study to visualize continuous changes in blood flow and oxygen utilization within contracted muscles during and after electrical muscle stimulation (EMS) using combined diffuse correlation and near-infrared spectroscopy. We found that initiating EMS increases blood flow at a rate comparable to that during voluntary (VOL) exercise but enhances oxygen extraction, resulting in higher oxygen consumption. Furthermore, EMS increased postexercise muscle perfusion and oxygen consumption compared with that after VOL exercise.

Neuromuscular electrical stimulation changes glucose, but not its variability in type 2 diabetes: a randomized clinical trial

Neuromuscular electrical stimulation (NMES) can be an alternative to conventional exercising. This randomized clinical trial evaluated the effect of NMES in type 2 diabetes patients. Twenty-eight individuals with type 2 diabetes were assigned to NMES (n=14) or NMES-placebo (n=14) applied to knee extensor muscles for 60 minutes. Glucose variability, microvascular function and endothelial function were evaluated through continuous glucose monitoring system, near infrared spectroscopy and flow-mediated dilatation, respectively. Glucose levels (mg/dl) decreased 2h (184 ± 11 vs 223 ±15), 3h (179 ± 12 vs 219 ±14) and 4h (177 ± 12 vs 212 ±12) after NMES, in comparison to NMES-placebo. No differences in glucose variability were found: coefficient of variation (%) at 0-6h (11.4±1.3 vs 11.4±1.2), 6-12h (9.8±1.0 vs 11.6±1.6), 12-18h (15.5±2.0 vs 11.4±2.1), 18-24h (12.8±2.3 vs 10.0±1.6); standard deviation (mg/dl) at 0-6h (21.6±2 vs 24.6±3.5), 6-12h (19.5±1.8 vs 20.3±2.8), 12-18h (29.9±3.5 vs 21.3±2.8),18-24h (22.8±4.1 vs 16.6±2.0) and mean amplitude of glycemic excursions (mg/dl) 54.9±25.0 vs 70.3±35.7. Endothelial and microvascular functions did not change. In conclusion, one acute NMES session was strong enough to trigger glucose reduction in individuals with type 2 DM, but it failed to induce any significant change in glucose variability, endothelial and microvascular functions.

Subtetanic neuromuscular electrical stimulation can maintain Wingate test performance but augment blood lactate accumulation

PURPOSE

Concentration- and time-dependent effect of lactate on physiological adaptation (i.e., glycolytic adaptation and mitochondrial biogenesis) have been reported. Subtetanic neuromuscular electrical stimulation (NMES) with voluntary exercise (VOLES) can increase blood lactate accumulation. However, whether this is also true that VOLES can enhance the blood lactate accumulation during sprint exercise is unknown. Thus, we investigated whether VOLES before the Wingate test can enhance blood lactate accumulation without compromising Wingate exercise performance.

METHODS

Fifteen healthy young males (mean [SD], age: 23 [4] years, body mass index: 22.0 [2.1] kg/m2) volunteered. After resting measurement, participants performed a 3-min intervention: VOLES (NMES with free-weight cycling) or voluntary cycling alone, which matched exercise intensity with VOLES (VOL, 43.6 [8.0] watt). Then, they performed the Wingate test with 30 min free-weight cycling recovery. The blood lactate concentration ([La]b) was assessed at the end of resting and intervention, and recovery at 1, 3, 5, 10, 20, and 30 min.

RESULTS

[La]b during intervention was higher with VOLES than VOL (P = 0.011). The increase in [La]b after the Wingate test was maintained for longer with VOLES than VOL at 10- and 20-min recovery (P = 0.014 and 0.023, respectively). Based on the Wingate test, peak power, mean power, and the rate of decline were not significantly different between VOLES and VOL (P = 0.184, 0.201, and 0.483, respectively).

CONCLUSION

The combination of subtetanic NMES with voluntary exercise before the Wingate test has the potential to enhance blood lactate accumulation. Importantly, this combined approach does not compromise Wingate exercise performance compared to voluntary exercise alone.

The neuromodulatory role of dopamine in improved reaction time by acute cardiovascular exercise

Acute cardiovascular physical exercise improves cognitive performance, as evidenced by a reduction in reaction time (RT). However, the mechanistic understanding of how this occurs is elusive and has not been rigorously investigated in humans. Here, using positron emission tomography (PET) with [11 C]raclopride, in a multi-experiment study we investigated whether acute exercise releases endogenous dopamine (DA) in the brain. We hypothesized that acute exercise augments the brain DA system, and that RT improvement is correlated with this endogenous DA release. The PET study (Experiment 1: n = 16) demonstrated that acute physical exercise released endogenous DA, and that endogenous DA release was correlated with improvements in RT of the Go/No-Go task. Thereafter, using two electrical muscle stimulation (EMS) studies (Experiments 2 and 3: n = 18 and 22 respectively), we investigated what triggers RT improvement. The EMS studies indicated that EMS with moderate arm cranking improved RT, but RT was not improved following EMS alone or EMS combined with no load arm cranking. The novel mechanistic findings from these experiments are: (1) endogenous DA appears to be an important neuromodulator for RT improvement and (2) RT is only altered when exercise is associated with central signals from higher brain centres. Our findings explain how humans rapidly alter their behaviour using neuromodulatory systems and have significant implications for promotion of cognitive health. KEY POINTS: Acute cardiovascular exercise improves cognitive performance, as evidenced by a reduction in reaction time (RT). However, the mechanistic understanding of how this occurs is elusive and has not been rigorously investigated in humans. Using the neurochemical specificity of [11 C]raclopride positron emission tomography, we demonstrated that acute supine cycling released endogenous dopamine (DA), and that this release was correlated with improved RT. Additional electrical muscle stimulation studies demonstrated that peripherally driven muscle contractions (i.e. exercise) were insufficient to improve RT. The current study suggests that endogenous DA is an important neuromodulator for RT improvement, and that RT is only altered when exercise is associated with central signals from higher brain centres.

Relationship Between Increased Oxygen Uptake and Lactate Production With Progressive Incremental Electrode Skeletal Muscle Stimulation: A Pilot Study

Background Belt electrode skeletal muscle stimulation (B-SES) is an alternative exercise therapy for those with difficulty performing voluntary exercise. However, it is unknown whether oxygen uptake (VO2) in B-SES is comparable to cardiopulmonary exercise test (CPX) as assessed by voluntary exercise. This study aimed to evaluate oxygen uptake (VO2) and lactate (LA) production in incremental B-SES compared to ergometer CPX and to determine the relationship with ergometer CPX. Methods This study included 10 healthy young Japanese participants. Using a crossover design, all participants underwent incremental B-SES CPX and ergometer CPX using a 20 W ramp. Serum lactic acid concentration (LA) was measured serially before, during, and after B-SES. The tolerability of B-SES was adjusted with the change in LA level (⊿LA). Results Peak VO2 during B-SES (14.1±3.3 mL/kg/min) was significantly lower than ergometer peak VO2 (30.2±6.2 mL/kg/min, P<0.001). B-SES peak VO2 was similar to the anaerobic threshold (AT) VO2 on ergometer CPX (15.1±2.6 mL/kg/min). LA (Rest: 1.4±0.3, Peak: 2.8±0.8 mmol) and plasma noradrenalin (Rest: 0.2±0.1, Peak: 0.4±0.1 ng/mL) levels increased after B-SES. No significant correlation was observed between B-SES peak VO2 and ergometer CPX. However, after adjusting for B-SES, tolerability, it (peak VO2 of B-SES /⊿LA) correlated with peak VO2 (r=0.688, p=0.028) on the ergometer. Conclusion Peak VO2 of the passively progressive B-SES almost reached the AT value of the ergometer CPX without adverse events. Peak VO2 of B-SES adjusted with ⊿LA may be used to predict peak VO2 in ergometer CPX.

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.

Cooling of male rat skeletal muscle during endurance-like contraction attenuates contraction-induced PGC-1α mRNA expression

This study aimed to determine effects of cooling on contraction-induced peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and vascular endothelial growth factor (VEGF) gene expression, phosphorylations of its related protein kinases, and metabolic responses. Male rats were separated into two groups; room temperature (RT) or ice-treated (COLD) on the right tibialis anterior (TA). The TA was contracted isometrically using nerve electrical stimulation (1-s stimulation × 30 contractions, with 1-s intervals, for 10 sets with 1-min intervals). The TA was treated before the contraction and during 1-min intervals with an ice pack for the COLD group and a water pack at RT for the RT group. The muscle temperature of the COLD group decreased to 19.42 ± 0.44°C (p < 0.0001, -36.4%) compared with the RT group after the experimental protocol. An increase in mRNA expression level of PGC-1α, not VEGF, after muscle contractions was significantly lower in the COLD group than in the RT group (p < 0.0001, -63.0%). An increase in phosphorylated AMP-activated kinase (AMPK) (p = 0.0037, -28.8%) and a decrease in glycogen concentration (p = 0.0231, +106.3%) after muscle contraction were also significantly inhibited by cooling. Collectively, muscle cooling attenuated the post-contraction increases in PGC-1α mRNA expression coinciding with decreases in AMPK phosphorylation and glycogen degradation.

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.

Electromyostimulation in sport

Electromyostimulation (EMS) is a widely used therapeutic tool of low-frequency electrotherapy in several areas of rehabilitation, with gradual use increasingly in sports as well. The main goal of our article is to approach the use of EMS in sports based on available studies. EMS can be called as a training method used to obtain muscle activation through externally applied electric currents to the muscles to achieve a functional increase in sports performance by training fast motor units. Even if, based on the available study database, there are no clear conclusions regarding the effectiveness and application of EMS in the sense of sports, we can say that EMS represents one of the means by which we can influence muscle functionality, not only in terms of rehabilitation, but also as a possible way of increasing sports performance.

Effects of 8-Week Electromyostimulation Training on Upper-Limb Muscle Activity and Respiratory Gas Analysis in Athletes with Disabilities

This study was aimed at verifying the efficacy of EMS training by investigating the changes in upper-limb muscle functions and energy expenditure in athletes with disabilities after an 8-week intervention of EMS training. We compared variations in muscle activity, respiratory gas, and symmetry index (SI) after an 8-week intervention in eight professional male athletes with disabilities wearing an electromyostimulation (EMS) suit (age: 42.00 ± 8.67 years, height: 1.65 ± 0.16 m, weight: 64.00 ± 8.72 kg, career length: 11.75 ± 3.83 years). For EMS training, each participant wore an EMS suit. EMS was applied to the upper-limb muscles pectoralis major and triceps at 40 °C water temperature, with a 25 Hz frequency (duty cycle 10%) for 15 min, followed by a 5 Hz frequency (duty cycle 5%) for 5 min. The pre- and post-intervention measurements were taken in the same way at a pre-set time (for 1 h, twice a week) for 8 weeks. Training involved a seated chest press, and the muscle activity (pectoralis major, triceps, and antebrachial muscles), upper-limb SI, and respiratory gas variables (maximal oxygen consumption (VO2), carbon dioxide output (VCO2), respiratory quotient (RQ), metabolic equivalents (METs), and energy expenditure per min (Energy expended per minute; EEm)) were analyzed. Variations pre- and post-intervention across the measured variables were analyzed. Regarding the change in muscle activity, significant variations were found in the pectoralis major right (p < 0.004), pectoralis major left (p < 0.001), triceps right (p < 0.002), and antebrachial right (p < 0.001). Regarding left-to-right SI, a positive change was detected in the pectoralis major and triceps muscles. Additionally, respiratory gas analysis indicated significant variations in VO2 (p < 0.001), VCO2 (p < 0.001), METs (p < 0.001), and EEm (p < 0.001). EMS training improved muscle strength and respiratory gas variables and is predicted to contribute to enhanced muscle function and rehabilitation training for athletes with disabilities.

Visceral fat loss by whole-body electromyostimulation is attenuated in male and absent in female older Non-Insulin-Dependent diabetes patients

INTRODUCTION

Type 2 diabetes and its reversal correlate with increases and decreases in visceral fat (VF). Resistance exercise reduces VF in healthy persons, but little is known in type 2 diabetes. Muscle contractions induced by whole-body electromyostimulation (WB-EMS) provide a very effective form of resistance training. We hypothesized that WB-EMS reduces VF and improves plasma glucose measures in older non-insulin dependent diabetes mellitus (NIDDM) males and females.

METHODS

A four-arm age-matched case control study was done on WB-EMS twice a week in older NIDDM patients (27 males, 18 females) compared with controls (15 males, 15 females). VAT area (VAT, cm² ), total fat mass (TFM, kg) and lean body mass (LBM, kg) were assessed by DEXA-scanning. HbA1c, fasting glucose and plasma lipoproteins were measured at baseline and after 4 months.

RESULTS

Baseline control VAT was higher in males than females (140.5 ± 35.6 vs. 96.7 ± 42.3, p < .001). In NIDDM, VAT was higher with no significant sex difference (206.5 ± 65.0 vs. 186.5 ± 60.5). In controls, WBEMS reduced VAT in males and females to similar extent (-16.9% and -16.4%, p < .001 vs. baseline) and in preference to TFM (-9.2% and -3.6%) or body weight loss (-2.8 and -2.1%). In NIDDM, VF loss was attenuated in males (-7.3%, p < .01) but completely absent in females. WBEMS reduced HbA1c and cholesterol and increased HDL levels (all p < .05) only in male NIDDM CONCLUSIONS: WBEMS induced VF loss in healthy older males and females an effect strongly attenuated in male and completely absent in female NIDDM patients. This questions the effectiveness of muscle contraction-induced VF lipolysis in NIDDM. Sex differences may dictate the success of resistance training in NIDDM, a subject that needs to be addressed in future studies.

The effect of neuromuscular electrical stimulation on serum glucose levels in children and adolescents with type-1 diabetes mellitus: a single group clinical trial

BACKGROUND

This study aimed to evaluate the effect of Neuromuscular Electrical Stimulation (NMES) on serum glucose level in children and adolescents with type-1 diabetes.

METHODS

This before-after, single-group, clinical trial was conducted on 29 patients with type-1 diabetes mellitus with the age range of 7-18 years. The patients underwent NMES in two 20-minute phases on the quadriceps and hamstrings muscles, three sessions per week for a period of 8 weeks. Fasting Blood Sugar (FBS), measured in two ways, by glucometer and laboratory testing, was considered as the primary outcome and the glycated hemoglobin (HbA1c) and the total daily dose (TDD) of insulin were measured as the secondary outcomes. The laboratory FBS and HbA1c were measured 1 day before the intervention (as a baseline value) and then 2 and 6 weeks after the last session of intervention. FBS by glucometer and total daily dose of insulin were recorded daily from 2 weeks before the intervention to the last day of the intervention and consequently, the weekly average of these variables was calculated and used for statistical analysis.

RESULTS

The serum level of FBS (measured by glucometer) and the total daily dose of insulin reduced significantly 2 weeks after beginning of intervention. The laboratory serum level of FBS decreased significantly in the second week after the end of intervention compared to the baseline values. Although the HbA1c level decreased at follow-up period (2 and 6 weeks after the intervention), it was not significant.

CONCLUSION

It seems that 8 weeks of NMES has beneficial effects on the reduction of FBS and TDD of insulin therefore, it could be suggested as the contributory treatment in management of children and adolescents with type-1 diabetes.

TRIAL REGISTRATION

The study was registered at https://fa.irct.ir/user/trial/51739/view (IRCT20100523003998N1) in date of 25/10/2020.

Acute Effects of Whole-Body Electromyostimulation on Energy Expenditure at Resting and during Uphill Walking in Healthy Young Men

The effects of the different electrical frequencies of whole-body electrical stimulation (WB-EMS) on energy expenditure (EE) and the respiratory exchange ratio (RER) remain poorly understood. This study aimed to determine the effects of different WB-EMS electrical frequencies on EE and the RER during supine resting and uphill walking. A total of 10 healthy and recreationally active men (21.6 ± 3.3 years old) participated in the present study. Participants completed two testing sessions in a randomized order. In each session, a variety of impulse frequencies (1 hertz (Hz), 2 Hz, 4 Hz, 6 Hz, 8 Hz, and 10 Hz) were applied in a randomized order, allowing a 10 min passive recovery between them. Oxygen consumption and carbon dioxide production were measured to calculate EE and the RER. All frequencies increased EE at rest (all p ≤ 0.001), with 4 Hz being the frequency producing the highest increase (Δ = 8.89 ± 1.49 kcal/min), as did 6 Hz (Δ = 8.05 ± 1.52 kcal/min) and 8 Hz (Δ = 7.04 ± 2.16 kcal/min). An increment in the RER at rest was observed with 4 Hz, 6 Hz, 8 Hz and 10 Hz (all p ≤ 0.016), but not with 1 Hz and 2 Hz (p ≥ 0.923). During uphill walking, the frequency that elicited the highest increase in EE was 6 Hz (Δ = 4.87 ± 0.84 kcal/min) compared to the unstimulated condition. None of the impulse frequencies altered the RER during uphill walking. WB-EMS increases EE in healthy young men both during resting and uphill walking.

Reversal and Remission of T2DM - An Update for Practitioners

Over the past 50 years, many countries around the world have faced an unchecked pandemic of obesity and type 2 diabetes (T2DM). As best practice treatment of T2DM has done very little to check its growth, the pandemic of diabesity now threatens to make health-care systems economically more difficult for governments and individuals to manage within their budgets. The conventional view has been that T2DM is irreversible and progressive. However, in 2016, the World Health Organization (WHO) global report on diabetes added for the first time a section on diabetes reversal and acknowledged that it could be achieved through a number of therapeutic approaches. Many studies indicate that diabetes reversal, and possibly even long-term remission, is achievable, belying the conventional view. However, T2DM reversal is not yet a standardized area of practice and some questions remain about long-term outcomes. Diabetes reversal through diet is not articulated or discussed as a first-line target (or even goal) of treatment by any internationally recognized guidelines, which are mostly silent on the topic beyond encouraging lifestyle interventions in general. This review paper examines all the sustainable, practical, and scalable approaches to T2DM reversal, highlighting the evidence base, and serves as an interim update for practitioners looking to fill the practical knowledge gap on this topic in conventional diabetes guidelines.

Acute Effects of Low-Intensity Electrical Stimulation on Segmental Arterial Stiffness

Electrical muscle stimulation (EMS) has traditionally been employed to improve muscle strength and glucose uptake. EMS may also reduce arterial stiffness, but little is known about whether low-intensity EMS reduces systemic and/or regional arterial stiffness. This study aimed to examine the effects of low-intensity EMS of the lower limbs on segmental arterial stiffness. Fourteen healthy subjects participated in experiments under two different protocols (control resting trial (CT) and electrical stimulation trial (ET)) in random order on separate days. The EMS was applied to the lower limbs at 4 Hz for 20 min at an intensity corresponding to an elevation of approximately 15 beats/min in pulse rate (10.7 ± 4.7% of heart rate reserve). Arterial stiffness was assessed by cardio-ankle vascular index (CAVI), CAVI₀, heart-ankle pulse wave velocity (haPWV), brachial-ankle pulse wave velocity (baPWV), heart-brachial pulse wave velocity (hbPWV), and carotid-femoral pulse wave velocity (cfPWV). In both trials, each parameter was measured at before (Pre) and 5 min (Post 1) and 30 min (Post 2) after trial. After the experiment, CT did not cause significant changes in any arterial stiffness parameters, whereas ET significantly reduced CAVI (from Pre to Post 1: −0.8 ± 0.5 unit p < 0.01), CAVI₀ (from Pre to Post 1: −1.2 ± 0.8 unit p < 0.01), haPWV (from Pre to Post 1: −47 ± 35 cm/s p < 0.01), and baPWV (from Pre to Post 1: −120 ± 63 cm/s p < 0.01), but not hbPWV or cfPWV. Arm diastolic blood pressure (BP) at Post 2 was slightly but significantly increased in the CT compared to Pre or Post 1, but not in the ET. Conversely, ankle diastolic and mean BPs at Post 1 were significantly reduced compared to Pre and Post 2 in the ET (p < 0.01). These findings suggest that low-intensity EMS of the lower limbs reduces arterial stiffness, but only in sites that received EMS.

Unjumbling Procedure in the Algorithmic Analysis of Biomechanical Torques Induced by Electrical Stimulation: Case Study of the Lower Limb

Functional Electrical Stimulation (FES) uses electrical pulses to cause muscles to contract synthetically. When muscles contract due to stimulation, torques are produced around joints attached to the muscle. It is important to understand torques being produced, for reasons such as safety and indirect fatigue measurement. Given the translatability of FES devices into the home for therapy, having ways to non-invasively measure muscle responses to stimulation is essential for understanding and diagnosing the biomechanical response of the human body. Here, we present data from a stimulation experiment examining knee joint torques (KJTs) arising when quadriceps are subjected to electrical stimulation. A novel algorithm for computing and summarizing KJT data into a series of simplified parameters was developed using MATLAB software. From this, we draw some conclusions about the effect of changing the stimulation duty cycle on the resultant KJT. We believe this method will provide researchers with a tool to measure torque in a semi-automated, convenient fashion.

Blood flow restriction and stimulated muscle contractions do not improve metabolic or vascular outcomes following glucose ingestion in young, active individuals

Glucose ingestion and absorption into the blood stream can challenge glycemic regulation and vascular endothelial function. Muscular contractions in exercise promote a return to homeostasis by increasing glucose uptake and blood flow. Similarly, muscle hypoxia supports glycemic regulation by increasing glucose oxidation. Blood flow restriction (BFR) induces muscle hypoxia during occlusion and reactive hyperemia upon release. Thus, in the absence of exercise, electric muscle stimulation (EMS) and BFR may offer circulatory and glucoregulatory improvements. In 13 healthy, active participants (27±3yr, 7 female) we tracked post-glucose (oral 100g) glycemic, cardiometabolic and vascular function measures over 120min following four interventions: 1) BFR, 2) EMS, 3) BFR+EMS or 4) Control. BFR was applied at 2min intervals for 30min (70% occlusion), EMS was continuous for 30min (maximum-tolerable intensity). Glycemic and insulinemic responses did not differ between interventions (partial η2=0.11-0.15, P=0.2); however, only BFR+EMS demonstrated cyclic effects on oxygen consumption, carbohydrate oxidation, muscle oxygenation, heart rate, and blood pressure (all P<0.01). Endothelial function was reduced 60min post-glucose ingestion across interventions and recovered by 120min (5.9±2.6% vs 8.4±2.7%; P<0.001). Estimated microvascular function was not meaningfully different. Leg blood flow increased during EMS and BFR+EMS (+656±519mL•min-1, +433±510mL•min-1; P<0.001); however, only remained elevated following BFR intervention 90min post-glucose (+94±94mL•min-1; P=0.02). Superimposition of EMS onto cyclic BFR did not preferentially improve post-glucose metabolic or vascular function amongst young, active participants. Cyclic BFR increased blood flow delivery 60min beyond intervention, and BFR+EMS selectively increased carbohydrate usage and reduced muscle oxygenation warranting future clinical assessments.

Four weeks of electrical stimulation improves glucose tolerance in a sedentary overweight or obese Hispanic population

INTRODUCTION/PURPOSE

Most US adults (54%) do not meet the minimum exercise recommendations by the American College of Sports Medicine. Neuromuscular electrical stimulation (NMES) is a novel alternate strategy to induce muscle contraction. However, the effectiveness of NMES to improve insulin sensitivity and energy expenditure is unclear. The purpose of this study was to investigate the effects of 4 weeks of NMES on glucose tolerance in a sedentary overweight or obese population.

METHODS

Participants (n = 10; age: 36.8 ± 3.8 years; BMI = 32 ± 1.3 kg/m2) were randomized into either control or NMES group. All participants received bilateral quadriceps stimulation (12 sessions; 30 min/session; three times/week at 50 Hz and 300 µs pulse width) altering pulse amplitude to either provide low-intensity sensory level (control; tingling sensation) or at high-intensity neuromuscular level (NMES; maximum tolerable levels with visible muscle contraction). Glucose tolerance was assessed by a 3-h oral glucose tolerance test (OGTT), and substrate utilization was measured by indirect calorimetry and body composition via dual X-ray absorptiometry at baseline and after 4 weeks of NMES intervention.

RESULTS

Control and NMES groups had comparable fasting blood glucose, glucose tolerance, substrate utilization, and muscle mass at baseline. Four weeks of NMES resulted in a significant improvement in glucose tolerance measured by OGTT, whereas no change was observed in the control group. There was no change in substrate utilization and muscle mass in both control and NMES groups.

CONCLUSION

NMES is a novel and effective strategy to improve glucose tolerance in an at-risk overweight or obese sedentary population.

Effect of Electrical Muscle Stimulation on Vascular Endothelial Function during Prolonged Sitting

OBJECTIVE

While prolonged sedentary behaviors (SBs) increase cardiovascular disease (CVD) risk, interrupting prolonged sitting (PS) with frequent light exercise reduces arterial functional decline. Skeletal muscle electrical stimulation (EMS) enhances peripheral circulation through passive muscle contraction, suggesting that EMS reduces CVD risk by providing an alternative to active exercise for prolonged SBs. This study aimed to investigate the effects of EMS to skeletal muscles during PS on the endothelial function of the brachial artery (BA).

METHODS

Study participants included 12 healthy adult men who were subjected to 15 min of supine rest, followed by 1 h of PS only (control [CON] trial), or 20 min of EMS to the lower extremities at 50% of the maximum tolerance intensity during PS (EMS trial). Flow-mediated dilation (FMD) of the BA was measured before and 30 min after PS, and normalized FMD (nFMD) was calculated.

RESULTS

The nFMD of the CON trial significantly decreased 30 min after PS completion (6.21% ± 1.13%) compared with that before PS (7.26% ± 0.73%), and there was no significant change in the EMS trial before and after PS. The EMS trial showed a significant increase in the nFMD 30 min after PS completion (1.14 ± 0.77) compared with that before PS (0.84 ± 0.43). However, no significant difference was observed in the CON trials.

CONCLUSION

Passive contraction of the lower extremity muscles by EMS increases BA nFMD, suggesting that prolonged sedentary lower extremity EMS use may reduce the risk of vascular endothelial dysfunction.

Effects of Acute Resistance Exercise with and without Whole-Body Electromyostimulation and Endurance Exercise on the Postprandial Glucose Regulation in Patients with Type 2 Diabetes Mellitus: A Randomized Crossover Study

Background: Long hyperglycemic episodes trigger complications in type 2 diabetes mellitus (T2DM) patients. Postprandial glucose excursions can be reduced by acute physical activity. However, it is not yet clear which type of exercise has the best effect on postprandial glucose levels. Methods: Six T2DM patients participated in three 20-min moderate-intensity exercise sessions after breakfast in a randomized order: resistance exercise with whole-body electromyostimulation (WB-EMS), resistance exercise without electromyostimulation (RES) and cycling endurance exercise (END). A continuous glucose monitoring system recorded glucose dynamics. Results: Postprandially-increased glucose levels decreased in all cases. Time to baseline (initial value prior to meal intake) was quite similar for WB-EMS, RES and END. Neither glucose area under the curve (AUC), nor time in range from the start of the experiment to its end (8 h later) differed significantly. A Friedman analysis of variance, however, revealed an overall significant difference for AUC in the post-exercise recovery phase (END seems to have superior effects, but post-hoc tests failed statistical significance). Conclusions: There are no notable differences between the effects of the different types of exercise on glucose levels, especially when comparing values over a longer period of time.

Electrically stimulated eccentric contraction during non-weight bearing knee bending exercise in the supine position increases oxygen uptake: A randomized, controlled, exploratory crossover trial

It is well known that prolonged bed rest induces muscle weakness, muscle atrophy, cardiovascular deconditioning, bone loss, a loss of functional capacity, and the development of insulin resistance. Neuromuscular electrical stimulation is anticipated to be an interventional strategy for disuse due to bed rest. A hybrid training system (HTS), synchronized neuromuscular electrical stimulation for voluntary exercise using an articular motion sensor, may increase the exercise load though bed rest. We assessed oxygen uptake or heart rate during knee bending exercise in the supine position on a bed both simultaneously combined with HTS and without HTS to evaluate exercise intensity on different days in ten healthy subjects (8 men and 2 women) by a randomized controlled crossover trial. The values of relative oxygen uptake during knee bending exercise with HTS were significantly greater than those during knee bending exercise without HTS (7.29 ± 0.91 ml/kg/min vs. 8.29 ± 1.06 ml/kg/min; p = 0.0115). That increment with HTS was a mean of 14.42 ± 13.99%. Metabolic equivalents during knee bending exercise with HTS and without HTS were 2.08 ± 0.26 and 2.39 ± 0.30, respectively. The values of heart rate during knee bending exercise with HTS were significantly greater than those during knee bending exercise without HTS (80.82 ± 9.19 bpm vs. 86.36 ± 5.50 bpm; p = 0.0153). HTS could increase exercise load during knee bending exercise which is easy to implement on a bed. HTS might be a useful technique as a countermeasure against the disuse due to bed rest, for example during acute care or the quarantine for infection prophylaxis.

Effects of neuromuscular electrical stimulation on energy expenditure and postprandial metabolism in healthy men

It is unclear whether neuromuscular electrical stimulation (NMES) has meaningful metabolic effects when users have the opportunity to self-select the intensity to one that can be comfortably tolerated. Nine healthy men aged 28 ± 9 y (mean ± SD) with a body mass index 22.3 ± 2.3 kg/m2 completed 3 trials involving a 2-h oral glucose tolerance test whilst, in a randomised counterbalanced order, (1) sitting motionless (SIT), (2) standing motionless (STAND); and (3) sitting motionless with NMES of quadriceps and calves at a self-selected tolerable intensity. The mean (95% confidence interval [CI]) total energy expenditure was greater in the NMES trial (221 [180-262] kcal/2 h) and STAND trial (178 [164-191] kcal/2 h) than during SIT (159 [150-167] kcal/2 h) (both, p < 0.05). This was primarily driven by an increase in carbohydrate oxidation in the NMES and STAND trials compared with the SIT trial (p < 0.05). Postprandial insulin iAUC was lower in both NMES and STAND compared with SIT (16.4 [7.7-25.1], 17 [7-27] and 22.6 [10.8-34.4] nmol·120 min/L, respectively; both, p < 0.05). Compared with sitting, both NMES and STAND increased energy expenditure and whole-body carbohydrate oxidation and reduced postprandial insulin concentrations in healthy men, with more pronounced effects seen with NMES. Self-selected NMES is a potential strategy for improving metabolic health. This trial is registered at ClinicalTrials.gov (ID: NCT04389736). Novelty: NMES at a comfortable intensity enhances energy expenditure and carbohydrate oxidation, and reduces postprandial insulinemia. Thus, self-selected NMES represents a potential strategy to improve metabolic health.

Effects of Arm-cranking Training with Electrical Muscle Stimulation on Vessel Function

This study aimed to determine whether arm-cranking training with electrical muscle stimulation (EMS) results in a greater improvement in vessel function than performing the same exercise without EMS. First, nine healthy young men performed two 20-min arm-cranking trials at 50% V˙O_2max with and without EMS applied to the lower limbs. The flow-mediated vasodilation (FMD) of the right brachial artery was measured using a high-resolution ultrasound device. Both FMD and normalized FMD were increased significantly after the arm-cranking with EMS trial, and significant differences were observed between the two trials. Second, 16 healthy adult men were randomly assigned to either the arm-cranking exercise training (A) group or arm-cranking training with EMS (A+EMS) group. The subjects were engaged in 20 min of arm-cranking at 50% V˙O_2max twice a week for 8 weeks with/without EMS applied to the lower limbs. The FMD increased significantly after A+EMS training session and the FMD in A+EMS group was significantly higher than that in the A group. These results indicate that acute/chronic endurance arm-cranking with EMS applied to the lower limbs improves the brachial artery endothelial function more markedly than the same exercise without EMS.

Development of the Protocol to Deliver Graded Stimulation Intensity on Lower Limbs Using Belt-shaped Electrode Skeletal Muscle Stimulation

Objectives:

Current advancements in neuromuscular electrical stimulation (NMES) include belt-shaped electrode skeletal muscle electrical stimulation (B-SES), which was developed to induce whole leg muscle contraction in a single session. Delivering the optimal amount of stimulation is critical in NMES; therefore, we set out to establish a method to determine the B-SES stimulation intensity needed to induce muscle contraction sufficient for clinical purposes.

Methods:

We used the Auto Tens Pro system (Homer Ion Laboratory), which is a B-SES device. Stimulation at 20 Hz was delivered for 5 s, followed by 2 s rest. Twenty-four patients who were hospitalized for musculoskeletal diseases were enrolled at two hospitals. Patients were randomly assigned to one of three groups of subjectively graded stimulation intensities: moderate, strong, or very strong. To achieve each target intensity, we developed a structured verbal instruction protocol that aimed to help therapists deliver the target level of stimulation. As a physiological assessment of muscle contraction, serum lactate levels were measured before and after a single 20-min B-SES session.

Results:

The electric current intensity required to achieve a target subjective muscle contraction gradually increase according to the subjective contraction level. The increase in serum lactate level was significantly larger in the very strong group than in the moderate group.

Conclusions:

B-SES stimulators have the potential to induce efficient muscle strengthening in patients with musculoskeletal diseases. The structured verbal protocol developed here could help therapists achieve the appropriate stimulation intensity for each patient.

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.

An integrated systematic approach for investigating microcurrent electrical nerve stimulation (MENS) efficacy in STZ-induced diabetes mellitus

Diabetes mellitus (DM) is a major metabolic disorder and an increasing health problem worldwide. Effective non-invasive therapies for DM are still lacking. Here, we have developed Microcurrent electrical nerve stimulation (MENS), a non-invasive therapy, and tested on 46 mice clustered into five groups, such as control, STZ-induced DM, and MENS treatment groups. Experimental results show that MENS treatment is able to improve seven biochemical indexes (e.g., hemoglobin A1c and glucose level). To investigate the mechanisms of MENS treatment on STZ-induced DM, we selected six representative samples to perform microarray experiments for several groups and developed an integrated Hierarchical System Biology Model (HiSBiM) to analyze these omics data. The results indicate that MENS can affect fatty acid metabolism pathways, peroxisome proliferator-activated receptor (PPAR) signaling pathway and cell cycle. Additionally, the DM biochemical indexes and omics data profiles of MENS treatment were found to be consistent. We then compared the therapeutic effects of MENS with anti-diabetic compounds (e.g., quercetin, metformin, and rosiglitazone), using the HiSBiM four-level biological functions and processes of multiple omics data. The results show MENS and these anti-diabetic compounds have similar effect pathways highly correlated to the diabetes processes, such as the PPAR signaling pathway, bile secretion, and insulin signaling pathways. We believe that MENS is an effective and non-invasive therapy for DM and our HiSBiM is an useful method for investigating multiple omics data.

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.

The effect of Ketogenic diet on vitamin D3 and testosterone hormone in patients with diabetes mellitus type 2

A keto diet is well-known for being a low carb diet in which the body produces ketones in the liver to be used as energy. When something high in carbs is eaten, the body will produce glucose and insulin. Glucose is the easiest molecule for the body to convert and use as energy, so it will be chosen over any other energy source. The aim of this study is to examine the effect of a ketogenic diet on type 2 diabetic patients and the effect it has on testosterone, vitamin D3, HDL, LDL levels, in comparison to non-ketogenic diet subjects. In the study, Type 2 diabetic patients undergoing a keto diet were selected and serum D3 levels and testosterone levels were examined and compared with control subjects. The result show a significant increase in testosterone hormone in patients with diabetes mellitus type 2 following a Ketogenic diet (mean± Std. Error 427.4±2.52) as compared with the control group (mean ± Std. Error 422.2±0.24) and as compared with patients with diabetes mellitus type 2 who are not following a Ketogenic diet (mean± Std. Error 151.4±1.41). The results show no significant level in LDL level in patients with diabetes mellitus type 2 following a Ketogenic diet (mean ± Std. Error 78.53±0.17), as compared to a control group (mean ± Std. Error 75.0.3±0.14) and no significant level in HDL level in patients with diabetes mellitus type 2 following a Ketogenic diet (mean± Std. Error 46.3±1.55), as compared with a control group (mean ± Std. Error 46.2±2.43), and with patients with diabetes mellitus type 2 who are not following a Ketogenic diet (mean ± Std. Error 45.1±1.55). The results show a significant increase in vitamin D3 level in patient with diabetes mellitus type 2 who are following a Ketogenic diet (mean ± Std. Error 53.5±0.32), as compared with a control group (mean± Std. Error 57±0.24), and with patients with diabetes mellitus type 2 who are not following a Ketogenic diet (mean ± Std. Error 25.1±1.55). Herein, normal vitamin D3 levels in patients corresponds to normal testosterone hormone levels. In conclusion, this study shows that in patients with diabetes mellitus type 2, following a ketogenic diet has a positive effect on the patients’ health.

Respiratory, cardiac and metabolic responses during electrical muscle stimulation in quadriceps muscle versus comparable voluntary muscle contractions

Electrical Muscle Stimulation (EMS) and voluntary muscle contraction (VMC) are both acceptable rehabilitative modalities to preserve muscle strength loss. The study aimed to compare respiratory, metabolic, and cardiac parameters during quadriceps muscle contraction (QMC) using either EMS or VMC with comparable generated low intensity muscle force. Thirty healthy non-smoker males, age 20-58 years with normal BMI and low to moderate physical activity, underwent two 20-min sessions of comparable QMC using EMS vs VMC at the same day. The BIODEX III isokinetic dynamometer was used to assess maximum isometric force and the comparable force generated during each condition (EMS vs VMC), while the METAMAX 3B portable metabolic system was used to measure continuously the physiological parameters. Tolerable EMS was used (mean: 33 ± 1.5 mA, at 75 Hz). Each contraction lasted 10 sec followed by 20 sec rest. Paired t-tests were used for comparisons between sessions. A relatively low proportion of maximum isometric force (EMS: 8.5% vs VMC: 8.6%) and torque (EMS: 16 ± 1.3 vs VMC: 16 ± 1.1 Nm) were generated during each session. Mean minute ventilation (EMS: 10.8 L vs VMC: 9.8 L), tidal volume (EMS: 0.6 L vs VMC: 0.5 L), O₂ uptake (EMS: 0.31 L/min vs VMC: 0.26 L/min) and O₂ pulse (EMS: 3.9 ml/beat vs VMC: 3.6 ml/beat) were different between sessions (p ≤ .05); while heart rate (EMS: 72 beats/min vs VMC: 71 beats/min) was equal. Quadriceps muscle EMS induces higher respiratory and metabolic responses compared to equal magnitude VMC in healthy males.

Molecular and neural adaptations to neuromuscular electrical stimulation; Implications for ageing muscle

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Muscle atrophy and functional declines observed with advancing age can be minimized via various NMES protocols.

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Animal models have shown that NMES induces motor axon regeneration and promotes axonal outgrowth and fibre reinnervation.

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The activation of BDNF-trkB contributes to promotion of nerve growth and survival and mediates neuroplasticity.

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NMES is able to regulate muscle protein homeostasis and elevate oxidative enzyme activity.

One of the most notable effects of ageing is an accelerated decline of skeletal muscle mass and function, resulting in various undesirable outcomes such as falls, frailty, and all-cause mortality. The loss of muscle mass directly leads to functional deficits and can be explained by the combined effects of individual fibre atrophy and fibre loss. The gradual degradation of fibre atrophy is attributed to impaired muscle protein homeostasis, while muscle fibre loss is a result of denervation and motor unit (MU) remodelling. Neuromuscular electrical stimulation (NMES), a substitute for voluntary contractions, has been applied to reduce muscle mass and functional declines. However, the measurement of the effectiveness of NMES in terms of its mechanism of action on the peripheral motor nervous system and neuromuscular junction, and multiple molecular adaptations at the single fibre level is not well described. NMES mediates neuroplasticity and upregulates a number of neurotropic factors, manifested by increased axonal sprouting and newly formed neuromuscular junctions. Repeated involuntary contractions increase the activity levels of oxidative enzymes, increase fibre capillarisation and can influence fibre type conversion. Additionally, following NMES muscle protein synthesis is increased as well as functional capacity. This review will detail the neural, molecular, metabolic and functional adaptations to NMES in human and animal studies.

Immediate effect of neuromuscular electrical stimulation on the abductor hallucis muscle: A randomized controlled trial

Hallux valgus (HV) is a foot deformity with deviation of the greater toe and the first metatarsal. There is little evidence on training the abductor hallucis muscle (AbdH) to treat HV because of the difficulty in implementing the necessary interventions. Although neuromuscular electrical stimulation (NMES) has been used to induce voluntary exercise, there is currently no study on NMES for AbdH. We aimed to verify the immediate effect of NMES on the AbdH muscle function. For the NMES group (n = 15), electrical stimulation was applied for 20 min. In the sham group (n = 15), the stimulating device was set but not turned on. Electromyogram, HV angle (HVA) at rest and during abduction of the big toe, and strength of the AbdH were evaluated. Analysis of covariance was used to investigate differences within groups using the baseline as the covariate. NMES significantly improved the maximal voluntary isometric contractions (%MVIC), HVA at exercise, and muscle strength (%MVIC: p = .00, HVA exercise: p = .00, AbdH strength: p = .00). HVA at rest showed no change (p = .12). Application of NMES on the AbdH muscle immediately improved its activity output, muscle strength, and HVA during exercise.

High-Intensity Focused Ultrasound Ablation Combined with Electrical Passive Exercise for Fast Removal of Body Fat

BACKGROUND

High-intensity focused ultrasound (HIFU) lipolysis still lacks treatment efficacy. The authors hypothesized that electrical stimulation of muscular groups can enhance the metabolism of free lipids released from HIFU-ablated adipocytes.

METHODS

Five-month-old, male Landrace swine, with an average initial weight of 95 kg, were divided randomly into sham, HIFU only, HIFU plus electrical stimulation I, and HIFU plus electrical stimulation II groups. Subcutaneous adipose tissue of the porcine abdomen was treated once by HIFU on days 1 of weeks 1, 3, and 5, and electrical stimulation of the quadriceps was performed once on the day 1 of weeks 1 through 6. The numbers of ultrasonic sonications were 70 per treatment for the HIFU-only and HIFU plus electrical stimulation I groups and 400 for the HIFU plus electrical stimulation II group. The measured data are expressed as medians (ranges).

RESULTS

The body weights of all pigs increased gradually with time. The waist circumferences below the sheath decreased from 97.7 ± 6.0 cm in week 1 and 97.9 ± 5.3 cm in week 3 to 96.4 ± 10.0 cm in week 6, and from 105.3 ± 5.1 cm and 101.2 ± 7.4 cm to 100.5 ± 6.1 cm for the HIFU plus electrical stimulation I and II groups, respectively, whereas they increased for the sham and HIFU-only groups. The reductions in the adipose tissue thickness were 0.59, 1.46, and 2.18 mm for the HIFU-only, HIFU plus electrical stimulation I, and HIFU plus electrical stimulation II groups, respectively, when the sham group increased by 1.42 mm. Follow-up blood analyses demonstrated no significant changes in lipid panel parameters from baseline values.

CONCLUSION

HIFU plus electrical stimulation can induce a substantial reduction in the waist circumference of pigs.

Design considerations for the development of neuromuscular electrical stimulation (NMES) exercise in cancer rehabilitation

Aim: The aim of this narrative review is to explore design considerations for effective neuromuscular electrical stimulation exercise prescription in cancer rehabilitation, with simultaneous consideration for fundamental principles of exercise training and the current state of the art in neuromuscular electrical stimulation technologies and application methodologies.Method: Narrative review.Results: First, we consider the key neuromuscular electrical stimulation exercise design considerations, with a focus on training objectives and individual training requirements and constraints for individuals with cancer. Here, we contend that concurrent, low and high frequency neuromuscular electrical stimulation exercise, individually prescribed and progressed may be optimal for enhancing physical function. Second, we review the appropriate literature to identify the most appropriate stimulation parameters (pulse frequency, intensity, duration and duty cycle) to deliver effective neuromuscular electrical stimulation in cancer rehabilitation.Conclusions: We propose an informed and innovative neuromuscular electrical stimulation exercise intervention design and provide practical information for clinicians and practitioners who may work with and implement neuromuscular electrical stimulation exercise in cancer.Implications for rehabilitationNeuromuscular electrical stimulation is an emerging technology in cancer rehabilitation to help provide an aerobic and muscle strengthening exercise stimulus.Neuromuscular electrical stimulation may help improve aerobic exercise capacity, muscle strength and augment quality of life.Current prescription in cancer lacks adherence to the fundamental principles of exercise training, which may negatively affect adherence.

Neuromuscular, hormonal and cardiovascular adaptations to eight-week HIIT and continuous aerobic training combined with neuromuscular electrical stimulation

BACKGROUND

Whether high-or-low intensity exercise coupled with neuromuscular electrostimulation (NMES) affect IGF-1 and IGFBP-1 is unknown. The scope of this study was to test whether 8-week high-intensity interval training (HIIT) and continuous aerobic training (CA) combined with/without NMES performed at 65% and 120% of VO2max on a cycle ergometer induce different metabolic adaptations.

METHODS

A randomized controlled trial with a parallel groups study design was used. Thirty healthy untrained male participants (age: 21.33±1.24 years, height: 177.80±5.97 cm, weight: 73.74±7.90 kg, lean body mass: 64.29±5.11 kg, percent body fat: 12.43±5.34%) voluntarily participated in this study. Six participants were allocated to Control, six to HIIT, six to HIIT+NMES, six to CA, and six to CA+NMES.

RESULTS

Pre- to post-test IVO2max, blood lactate concentrations, O2 kinetics, peak torques at 60o/s and 180o/s were found statistically significant (P<0.05, P<0.001). IGF-1 pre 15 min in CA and IGF-1 post 30 min in HIIT group was found significantly higher compared to control group (16.93±8.40 vs. 6.05±4.25, P=0.024; 10.80±3.94 vs. 6.15±2.56, P=0.037), respectively. Additionally, IGFBP-1 were found significantly higher in CA+NMES group than HIIT group (0.95±0.67 vs. 1.23±0.56). Eight week post IGF-1/IGFBP-1 ratios were found higher in pre 15 min, post 30 min and post 24 h compared to baseline pre 15 min, post 30 min and post 24 h measurements in all groups (8.92±4.72 vs. 3.93±3.14; 9.41±3.72 vs. 3.99±1.76; 8.63±3.01 vs. 5.89±3.01, respectively). Also, IGFBP-1 post 30 min was significantly lower in HIIT+NMES while CA group showed significantly lower baseline and 24 h post IGFBP-1 compared to pre-test measurements (Z=-3.20, P=0.001; Z=-3.72, P=0.000; Z=-2.93, P=0.000).

CONCLUSIONS

HIIT and CA training induce different stimuli on IGF-1 and IGFBP-1 and NMES application combined with high-and-low intensity exercise is highly effective in improving athletic performance.

Seven Weeks of Jump Training with Superimposed Whole-Body Electromyostimulation Does Not Affect the Physiological and Cellular Parameters of Endurance Performance in Amateur Soccer Players

Intramuscular density of monocarboxylate-transporter (MCT) could affect the ability to perform high amounts of fast and explosive actions during a soccer game. MCTs have been proven to be essential for lactate shuttling and pH regulation during exercise and can undergo notable adaptational changes depending on training. The aim of this study was to evaluate the occurrence and direction of potential effects of a 7-weeks training period of jumps with superimposed whole-body electromyostimulation on soccer relevant performance surrogates and MCT density in soccer players. For this purpose, 30 amateur soccer players were randomly assigned to three groups. One group performed dynamic whole-body strength training including 3 x 10 squat jumps with WB-EMS (EG, n = 10) twice a week in addition to their daily soccer training routine. A jump training group (TG, n = 10) performed the same training routine without EMS, whereas a control group (CG, n = 8) merely performed their daily soccer routine. 2 (Time: pre vs. post) x 3 (group: EG, TG, CG) repeated measures analyses of variance (rANOVA) revealed neither a significant time, group nor interaction effect for VO₂peak, Total Time to Exhaustion and La_max as well as MCT-1 density. Due to a lack of task-specificity of the underlying training stimuli, we conclude that seven weeks of WB-EMS superimposed to jump exercise twice a week does not relevantly influence aerobic performance or MCT density.

Effects of whole-body ELECTROMYOSTIMULATION on health and performance: a systematic review

BACKGROUND

Whole-body electrical myostimulation (WB-EMS) is a relatively recent training methodology that has been extraordinarily used in recent years. However, there is a lack of consensus on the effectiveness of WB-EMS in the situations in which its use has been largely popularized. The objective of this systematic review was to determine the effects produced by WB-EMS.

METHODS

A search of PubMed, Web of Science, Scopus and Cochrane was performed to identify all the studies that have applied electrical stimulation in lower and upper limbs simultaneously and that have clearly presented their protocols for the training and application of the stimulation. The last search was performed on September 9, 2018. Studies written in English or German were included.

RESULTS

A total of 21 articles met the inclusion criteria and were analyzed following the guidelines of the Cochrane Guide for Systematic Reviews. Nineteen studies analyzed the chronic effects of WB-EMS, and 2 analyzed acute effects with a total of 505 subjects (310 men and 195 women). In total, 35% were moderately trained, and 65% were sedentary subjects. Different dependent variables were studied, such as anthropometric parameters, strength parameters, energy expenditure, psychophysiological parameters and blood parameters. There is a lack of randomized controlled studies, and the studies included exhibit a moderate to high level of risk of bias.

CONCLUSIONS

Given the limited number of available studies on WB-EMS, the scarce amount of scientific evidence found does not allow definitive conclusions about its effects; therefore, future studies about WB-EMS are necessary.

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

Purpose

Since neuromuscular electrical stimulation (NMES) can recruit high-threshold motor units and enhance glucose metabolism, the combination of NMES and voluntary low-intensity exercise would induce both anerobic and aerobic energy consumptions and this type of exercise could be more efficient and effective than conventional exercise regimens. We aimed to investigate metabolic responses and muscle fatigue during whole body NMES (WB-NMES), voluntary exercise, and their combination.

Methods

The blood lactate concentration and maximal voluntary contraction were measured before and after specified exercises: WB-NMES (E), voluntary exercise (V), and their combination (VE), and expired gas was sampled during the exercises in thirteen healthy young men. Each exercise was conducted for 15 min and interval between exercise was > 48h.

Results

Energy expenditure and V˙O2 relative to the body mass during VE were significantly higher than during V and E (p < 0.05). The Respiratory gas exchange ratio (RER) during both E and VE was higher than during V (p < 0.05), and the blood lactate concentration after VE was significantly higher than after V and E (p < 0.05). Although V˙O2 relative to the body mass was 18.6 ± 3.1 ml/min/kg and the metabolic equivalent was 5.31 ± 0.89 Mets, the blood lactate concentration reached 7.5 ± 2.7 mmol/L after VE.

Conclusion

These results suggest that the combination of WB-NMES and voluntary exercise can enhance the metabolic response to a level equivalent to high intensity exercise under the net physiological burden of low-middle intensity exercises.

Hypoglossal-facial 'side'-to-side Neurorrhaphy Combined with Electrical Myostimulation for Facial Palsy in Rats

Introduction This study investigated the effect of combining hypoglossal-facial nerve “side”-to-side neurorrhaphy and electrical myostimulation in a rat model of facial palsy.

Methods Rats with facial nerve crush injury were subjected to control condition, monotherapy of either neurorrhaphy or electrical myostimulation, or bitherapy of the two treatments. After 1, 3, and 6 months, rats were performed the facial symmetry evaluation, electrophysiological examination and the retrograde labeling of motor neurons.

Results As early as 3 months after injury, face symmetry significantly improved in rats of the bitherapy group. At 3 or 6 months after injury, either the parameters of electrophysiological examination or the number of labeled motor neurons were significantly increased in the bitherapy group than in any other group.

Discussion The combination of neurorrhaphy and electrical myostimulation effectively promoted the functional recovery after facial nerve crush injury.

Impact of prolonged neuromuscular electrical stimulation on metabolic profile and cognition-related blood parameters in type 2 diabetes: A randomized controlled cross-over trial

AIMS

This study aimed to examine the effect of prolonged neuromuscular electrical stimulation (NMES) on the metabolic profile and cognition-related blood parameters in patients with type 2 diabetes mellitus (T2DM).

METHODS

Fourteen patients with T2DM (63.2 ± 3.0 years, 76.1 ± 3.5 kg) participated in a randomized controlled cross-over study, in which 8-week-long NMES interventions were performed on both legs. The NMES training protocol consisted of 40-min sessions, 5 days per week, for 8 weeks. The relative changes in glucose and lipid profiles, and cognition-related blood parameters were evaluated.

RESULTS

NMES training induced significant changes in the fasting glucose concentration (p < 0.05) and percent body fat (p < 0.05), although there were no significant changes in HbA1c and blood lipid levels (p ≥ 0.05). The change in plasma brain-derived neurotrophic factor (BDNF) levels was significantly higher in the NMES period than in the control period (p < 0.05).

CONCLUSIONS

This study showed that an 8-week NMES training program could induce greater changes in the blood glucose concentration, percent body fat, and plasma BDNF levels than the control intervention in patients with T2DM. NMES training might prove to be an alternative exercise method for patients who might have difficulties in performing adequate voluntary exercise.

Effectiveness evaluation of whole-body electromyostimulation as a postexercise recovery method

BACKGROUND

Whole-body electromyostimulation (WB-EMS) devices are now being used in health and sports training, although there are few studies investigating their benefits. The objective of this research was to evaluate the effectiveness of WB-EMS as a postexercise recovery method and compare it with other methods like active and passive recovery.

METHODS

The study included nine trained men (age =21±1 years, height =1.77±0.4 m, mass =62±7 kg). Three trials were performed in three different sessions, 1 week apart. Each trial, the participants completed the same exercise protocol and a different recovery method each time. A repeated measures design was used to check the basal reestablishing on several physiological variables (lactate, heart rate, percentage of tissue hemoglobin saturation, temperature, and neuromuscular fatigue) and to evaluate the quality of recovery. The non-parametric Wilcoxon and Friedman ANOVA tests were used to examine the differences between recovery methods.

RESULTS

The results showed no differences between methods in the physiological and psychological variables analyzed. Although, the blood lactate concentration showed borderline statistical significance between methods (P=0.050). Likewise, WB-EMS failed to recover baseline blood lactate concentration (P=0.021) and percentage of tissue hemoglobin saturation (P=0.023), in contrast to the other two methods.

CONCLUSIONS

These findings suggest that WB-EMS is not a good recovery method because the power of reestablishing of several physiological and psychological parameters is not superior to other recovery methods like active and passive recovery.

Neuromuscular electrical stimulation improves skeletal muscle regeneration through satellite cell fusion with myofibers in healthy elderly subjects

The aim of this study was to determine whether neuromuscular electrical stimulation (NMES) affects skeletal muscle regeneration through a reduction of oxidative status in satellite cells of healthy elderly subjects. Satellite cells from the vastus lateralis skeletal muscle of 12 healthy elderly subjects before and after 8 wk of NMES were allowed to proliferate to provide myogenic populations of adult stem cells [myogenic precursor cells (MPCs)]. These MPCs were then investigated in terms of their proliferation, their basal cytoplasmic free Ca2+concentrations, and their expression of myogenic regulatory factors ( PAX3, PAX7, MYF5, MYOD, and MYOG) and micro-RNAs (miR-1, miR-133a/b, and miR-206). The oxidative status of these MPCs was evaluated through superoxide anion production and superoxide dismutase and glutathione peroxidase activities. On dissected single skeletal myofibers, the nuclei were counted to determine the myonuclear density, the fiber phenotype, cross-sectional area, and tension developed. The MPCs obtained after NMES showed increased proliferation rates along with increased cytoplasmic free Ca2+concentrations and gene expression of MYOD and MYOG on MPCs. Muscle-specific miR-1, miR-133a/b, and miR-206 were upregulated. This NMES significantly reduced superoxide anion production, along with a trend to reduction of superoxide dismutase activity. The NMES-dependent stimulation of muscle regeneration enhanced satellite cell fusion with mature skeletal fibers. NMES improved the regenerative capacity of skeletal muscle in elderly subjects. Accordingly, the skeletal muscle strength and mobility of NMES-stimulated elderly subjects significantly improved. NMES may thus be further considered for clinical or ageing populations.

NEW & NOTEWORTHY The neuromuscular electrical stimulation (NMES) effect on skeletal muscle regeneration was assessed in healthy elderly subjects for the first time. NMES improved the regenerative capacity of skeletal muscle through increased myogenic precursor cell proliferation and fusion with mature myofibers. The increased cytoplasmic free Ca2+concentration along with MYOD, MYOG, and micro-RNA upregulation could be related to reduced O2·−production, which, in turn, favors myogenic regeneration. Accordingly, the skeletal muscle strength of NMES-stimulated lower limbs of healthy elderly subjects improved along with their mobility.

Rehabilitation Treatment and Progress of Traumatic Brain Injury Dysfunction

Traumatic brain injury (TBI) is a major cause of chronic disability. Worldwide, it is the leading cause of disability in the under 40s. Behavioral problems, mood, cognition, particularly memory, attention, and executive function are commonly impaired by TBI. Spending to assist, TBI survivors with disabilities are estimated to be costly per year. Such impaired functional outcomes following TBI can be improved via various rehabilitative approaches. The objective of the present paper is to review the current rehabilitation treatment of traumatic brain injury in adults.

Using the Hephaistos orthotic device to study countermeasure effectiveness of neuromuscular electrical stimulation and dietary lupin protein supplementation, a randomised controlled trial

Purpose

The present study investigated whether neuromuscular electrical stimulation for 20 min twice a day with an electrode placed over the soleus muscle and nutritional supplementation with 19 g of protein rich lupin seeds can reduce the loss in volume and strength of the human calf musculature during long term unloading by wearing an orthotic unloading device.

Methods

Thirteen healthy male subjects (age of 26.4 ± 3.7 years) wore a Hephaistos orthosis one leg for 60 days during all habitual activities. The leg side was randomly chosen for every subject. Six subjects only wore the orthosis as control group, and 7 subjects additionally received the countermeasure consisting of neuromuscular electrical stimulation of the soleus and lateral gastrocnemius muscles and lupin protein supplementation. Twenty-eight days before and on the penultimate day of the intervention cross-sectional images of the calf muscles were taken by magnetic resonance imaging (controls n = 5), and maximum voluntary torque (controls n = 6) of foot plantar flexion was estimated under isometric (extended knee, 90° knee flexion) and isokinetic conditions (extended knee), respectively.

Results

After 58 days of wearing the orthosis the percentage loss of volume in the entire triceps surae muscle of the control subjects (-11.9 ± 4.4%, mean ± standard deviation) was reduced by the countermeasure (-3.5 ± 7.2%, p = 0.032). Wearing the orthosis generally reduced plantar flexion torques values, however, only when testing isometric contraction at 90° knee ankle the countermeasure effected a significantly lower percentage decrease of torque (-9.7 ± 7.2%, mean ± SD) in comparison with controls (-22.3 ± 11.2%, p = 0.032).

Conclusion

Unloading of calf musculature by an orthotic device resulted in the expected loss of muscle volume and maximum of plantar flexion torque. Neuromuscular electrical muscle stimulation and lupin protein supplementation could significantly reduce the process of atrophy.

Trial registration

ClinicalTrials.gov, identifier NCT02698878

Respiratory flow and vital signs associated with the intensity of functional electrical stimulation delivered to human abdominal muscles during quiet breathing

[Purpose] The purpose of this study was to examine the effects of increasing the intensity of functional electrical stimulation delivered to abdominal muscles during quiet breathing on respiratory flow, vital signs and pain in healthy subjects. [Subjects and Methods] Electrical stimulation was delivered bilaterally using one pair of high-conductivity gel-skin plate electrodes, placed on both sides of the abdomen, to nine healthy males. Subjects were required to breathe normally through a face mask for 2 minutes while in a supine position. The stimulation intensity was incrementally increased by 10 mA until reaching 100 mA. Respiratory parameters, vital signs and pain based on the visual analog scale were measured for each intensity of electrical stimulation. [Results] Transcutaneous oxygen saturation showed a slight upward trend in association with increasing stimulation intensity, but there were no significant changes in pulse or blood pressure. Respiratory flow, tidal volume, and minute ventilation increased significantly as the stimulation intensity rose. [Conclusion] This study revealed that functional electrical stimulation can be safely delivered to human abdominal muscles without causing vital sign abnormalities. It was also found that the appropriate intensity level of electrical stimulation for achieving effects on respiratory flow while also minimizing pain is 60–80 mA.

Stair ascending-descending exercise accelerates the decrease in postprandial hyperglycemia more efficiently than bicycle exercise

OBJECTIVE

Stair climbing-descending exercise (ST-EX) is a convenient method to increase exercise intensity. We compared the acute effect of ST-EX on lowering postprandial hyperglycemia with that of constant bicycle exercise (BI-EX) performed at the same heart rate (HR).

RESEARCH DESIGN AND METHODS

Seven people with type 2 diabetes and seven with impaired glucose tolerance volunteered for this study. The step rate for ST-EX and work rate for BI-EX were individually determined to correspond to high-moderate to low-vigorous intensity (HR ~130 beats per minute). For the ST-EX trial, the subjects performed 16 repetitions of walking down one flight of stairs followed by climbing up to the starting point (~8 min in duration) 90 min after consuming a test meal. For the BI-EX trial, the subjects performed a constant pedaling exercise for the same duration at the same time after the meal.

RESULTS

The reduction in blood glucose (BG) level between 90 and 105 min after a meal was significantly greater for ST-EX (-4.0±0.7mmol/L) than for BI-EX (-2.7±0.9mmol/L). The net reduction in BG between 90 and 105 min was also significantly greater for ST-EX (-3.2±0.7mmol/L) than for BI-EX (-2.0±0.6mmol/L). Serum insulin levels did not differ between the groups. Oxygen consumption for ST-EX was higher than that for BI-EX, but the blood lactate level and respiratory exchange ratio (RER) for ST-EX were lower than those for BI-EX.

CONCLUSIONS

Compared with BI-EX performed at the same HR, ST-EX more rapidly decreased postprandial BG level with lower blood lactate and RER responses. A short bout of ST-EX may be clinically useful to acutely ameliorate BG levels after meals.

Effect of Peripheral Electrical Stimulation (PES) on Nocturnal Blood Glucose in Type 2 Diabetes: A Randomized Crossover Pilot Study

Background

Regulation of hepatic glucose production has been a target for antidiabetic drug development, due to its major contribution to glucose homeostasis. Previous pre-clinical study demonstrated that peripheral electrical stimulation (PES) may stimulate glucose utilization and improve hepatic insulin sensitivity. The aim of the present study was to evaluate safety, tolerability, and the glucose-lowering effect of this approach in patients with type 2 diabetes (T2DM).

Methods

Twelve patients with T2DM were recruited for an open label, interventional, randomized trial. Eleven patients underwent, in a crossover design, an active, and a no-intervention control periods, separated with a two-week washout phase. During the active period, the patients received a daily lower extremity PES treatment (1.33Hz/16Hz burst mode), for 14 days. Study endpoints included changes in glucose levels, number of hypoglycemic episodes, and other potential side effects. Endpoints were analyzed based on continuous glucose meter readings, and laboratory evaluation.

Results

We found that during the active period, the most significant effect was on nocturnal glucose control (P < 0.0004), as well as on pre-meal mean glucose levels (P < 0.02). The mean daily glucose levels were also decreased although it did not reach clinical significance (P = 0.07). A reduction in serum cortisol (P < 0.01) but not in insulin was also detected after 2 weeks of treatment. No adverse events were recorded.

Conclusions

These results indicate that repeated PES treatment, even for a very short duration, can improve blood glucose control, possibly by suppressing hepatic glucose production. This effect may be mediated via hypothalamic-pituitary-adrenal axis modulation.

Trial registration

ClinicalTrials.gov NCT02727790