Neuromuscular Electrical Stimulation Sessions Research Articles

Safety and Feasibility of Neuromuscular Electrical Stimulation in Patients with Extracorporeal Membrane Oxygenation.

Background/Objectives: The aim of this study was to investigate the feasibility and safety of neuromuscular electrical stimulation (NMES) in patients on extracorporeal membrane oxygenation (ECMO) and thoroughly assess any potential adverse events. Methods: We conducted a prospective observational study assessing safety and feasibility, including 16 ICU patients on ECMO support who were admitted to the cardiac surgery ICU from January 2022 to December 2023. The majority of patients were females (63%) on veno-arterial (VA)-ECMO (81%), while the main cause was cardiogenic shock (81%) compared to respiratory failure. Patients underwent a 45 min NMES session while on ECMO support that included a warm-up phase of 5 min, a main phase of 35 min, and a recovery phase of 5 min. NMES was implemented on vastus lateralis, vastus medialis, gastrocnemius, and peroneus longus muscles of both lower extremities. Two stimulators delivered biphasic, symmetric impulses of 75 Hz, with a 400 μsec pulse duration, 5 sec on (1.6 sec ramp up and 0.8 sec ramp down) and 21 sec off. The intensity levels aimed to cause visible contractions and be well tolerated. Primary outcomes of this study were feasibility and safety, evaluated by whether NMES sessions were successfully achieved, and by any adverse events and complications. Secondary outcomes included indices of rhabdomyolysis from biochemical blood tests 24 h after the application of NMES. Results: All patients successfully completed their NMES session, with no adverse events or complications. The majority of patients achieved type 4 and 5 qualities of muscle contraction. Conclusions: NMES is a safe and feasible exercise methodology for patients supported with ECMO.

Specific changes in contractive functions and skeletal muscle architecture in humans in response to the use of two protocols of unmodulated neuro-muscular electrostimulation

The purpose of this study was to study the effect of unmodulated low-frequency superficial of neuromuscular electrical stimulation (NMES) of 30 and 60 min/day for 7 weeks on the force, velocity-strength properties of the triceps surae muscle (TS) and architecture (lengths and angles of fascicles) of human the medial gastrocnemius muscle (MG). Many studies have examined the effect of training intensity (percentage of maximal voluntary isometric contraction — MVC) during NMES on muscle force response. However, no study has examined the effect of the number of NMES sessions per day over 7 weeks on changes in the TS strength. Ten healthy volunteers (23.2 ± 3.2 years; age range 18–28 years) volunteered for the study and were randomly assigned to group 1 (30 min NMES) and group 2 (60 min NMES) 5 times a day. NMES for a 7-week period, a total of 35 NMES workouts Isometric triceps calf strength was recorded with a Biodex isokinetic dynamometer. The longitudinal ultrasonic images of the MG was measured in vivo using the B-mode Edge ultrasound system. After a 7-week training period, MVC and voluntary maximal “explosive” strength differed significantly between groups. Based on electrical stimulation parameters and healthy subjects in this study, electrical training caused an increase in foot extensor muscle strength and a gradient in voluntary explosive strength when used for 5 training per week for 30 min for 7 weeks.

The effect of neuromuscular electrical stimulation on the human skeletal muscle transcriptome.

The influence on acute skeletal muscle transcriptomics of neuromuscular electrical stimulation (NMES), as compared to established exercises, is poorly understood. We aimed to investigate the effects on global mRNA-expression in the quadriceps muscle early after a single NMES-session, compared to the effects of voluntary knee extension exercise (EX), and to explore the discomfort level. Global vastus lateralis muscle gene expression was assessed (RNA-sequencing) in 30 healthy participants, before and 3 h after a 30-min session of NMES and/or EX. The NMES-treatment was applied using textile electrodes integrated in pants and set to 20% of each participant's pre-tested MVC mean (±SD) 200 (±80) Nm. Discomfort was assessed using Visual Analogue Scale (VAS, 0-10). The EX-protocol was performed at 80% of 1-repetition-maximum. NMES at 20% of MVC resulted in VAS below 4 and induced 4448 differentially expressed genes (DEGs) with 80%-overlap of the 2571 DEGs of EX. Genes well-known to be up-regulated following exercise, for example, PPARGC1A, ABRA, VEGFA, and GDNF, were also up-regulated by NMES. Gene set enrichment analysis demonstrated many common pathways after EX and NMES. Also, some pathways were exclusive to either EX, for example, muscle tissue proliferation, or to NMES, for example, neurite outgrowth and connective tissue proliferation. A 30-min NMES-session at 20% of MVC with NMES-pants, which can be applied with an acceptable level of discomfort, induces over 4000 DEGs, of which 80%-overlap with DEGs of EX. NMES can induce exercise-like molecular effects, that potentially can lead to health and performance benefits in individuals who are unable to perform resistance exercise.

Immediate Effects of Blood Flow Restriction Combined with Neuromuscular Electrical Stimulation in Female Amateur Football Players: A Pilot Trial

We aimed to investigate the acute effects of blood flow restriction (BFR) combined with neuromuscular electrical stimulation (NMES) on muscle strength, thigh circumference, and knee joint reposition sense in female amateur football players, as well as to determine whether this procedure is safe. Methods: This was a pilot trial. Twenty female amateur football players were randomized into two groups: group 1 (n = 10) received a single NMES session; group 2 (n = 10) received NMES + BFR. The measured variables included maximal voluntary eccentric contraction (MVEC) and maximal voluntary concentric contraction (MVCC), thigh circumference, and knee joint reposition sense test. The type of electrical current used was TENS (symmetrical biphasic rectangular pulse, 350 μs, and 50 Hz), combined simultaneously with active knee extension (75 repetitions in 4 sets, 20% MVCC, 30 s rest between sets), for both groups. Group 2 had BFR added (80% of arterial occlusion pressure). Results: Statistically significant differences (p ≤ 0.05) were obtained for thigh circumference in both groups. The comparison between groups did not show statistically significant differences (p ≤ 0.05) in MVEC, MVCC, thigh circumference, or the knee joint reposition sense test. Conclusions: Both the isolated NMES intervention and its combination with BFR induced immediate changes in thigh circumference without impairing the muscle strength or proprioceptive ability of the football players. However, these results should be interpreted with caution, and future studies including a control group and isolated BFR application are needed.

Effect of neuromuscular electrical stimulation and early physical activity on ICU-acquired weakness in mechanically ventilated patients: A randomized controlled trial.

Intensive care unit-acquired weakness (ICU-AW) is common in critically ill patients and increases the duration of mechanical ventilation (MV) and weaning time. Early mobilization, range of motion (ROM) exercises, and neuromuscular electrical stimulation (NMES) can prevent ICU-AW by maintaining muscle mass. However, studies highlighting the effects of combining NMES with early physical activity in ICU patients are limited. To evaluate the effect of NMES and early physical activity on ICU-AW in mechanically ventilated patients. A single-blinded randomized controlled trial was conducted in Alexandria, Egypt. Patients were randomly assigned to one of four groups: NMES, ROM, combined therapy (ROM + NMES), or conventional care (control group). The Medical Research Council (MRC) scale was used to assess the ICU-AW for the study patients over a 7-day period. The duration of the patient's MV and ICU stays were recorded. Of the 180 patients who were assessed for eligibility, 124 were randomly assigned to one of four groups: 32 patients in ROM exercises, 30 in NMES, 31 in combined therapy (ROM + NMES), and 31 in the control group. On day 7, ROM + NMES and NMES groups showed higher MRC scores than ROM and control groups (50.37 ± 2.34, 49.77 ± 2.19, 44.97 ± 3.61, and 41.10 ± 3.84, respectively). ANOVA test results indicated significant differences (p < .001) across the four groups. ICU-AW occurred in 0% of the ROM + NMES group, 60% of the ROM group, 13% of the NMES group, and 100% of the control group (p < .001). The MV duration (in days) in the ROM + NMES group was shorter (12.80 ± 3.800) than in the ROM, NMES, or control groups (21.80 ± 4.460, 18.73 ± 4.748, and 20.70 ± 3.932, respectively). ICU-LOS was shorter in the ROM + NMES group (17.43 ± 3.17 days) compared with the ROM group (22.53 ± 4.51 days), the NMES group (21.10 ± 5.0 days), and the control group (21.50 ± 4.42 days) with significant differences (p < .001) between the four groups. Daily sessions of NMES and early physical activity were well tolerated, preserved muscle strength, prevented ICU-AW, and decreased the duration of the MV and ICU stay. The findings of this study support the use of NMES and early physical exercises by critical care nurses as part of routine care for critically ill patients.

High-vs medium-frequency neuromuscular electrical stimulation protocols on muscle mass in Intensive Care Unit patients, a pilot study

Aim: The aim of the present study was to investigate whether a high-frequency (HF) neuromuscular electrical stimulation (NMES) protocol could result in a smaller loss of muscle mass than a moderate-frequency (MF) protocol in ICU patients. Methods and materials: In this randomized pilot control trial, patients of the two intervention groups followed daily NMES sessions from the day of ICU admission until the tenth day. All study groups received physiotherapy in terms of usual care. Muscle layer thickness was assessed with ultrasound in the vastusintermedius (VI) and rectus femoris (RF) muscle to evaluate changes in muscle mass. Results: Totally 58 patients were allocated into three groups and 29 were finally analyzed (control: 10, MF: 12, HF: 7). Significant differences (p=0.05) between control and pooled NMES groups were observed for the right RF and VI. Significant differences in favor of HF vs MF group were observed for the left RF (3.6±15.3 vs 7.2±7.9% respectively, p=0.04). No differences were found regarding the number of sessions and presence of oedema (p&gt;0.05), while strength of contraction during sessions tended to be somewhat higher in the HF (p=0.09). Conclusion: HF may be more effective than MF to prevent muscle mass loss in ICU patients. More studies are needed to determine the optimal NMES characteristics.

Early Neuromuscular Electrical Stimulation Preserves Muscle Size and Quality and Maintains Systemic Levels of Signaling Mediators of Muscle Growth and Inflammation in Patients with Traumatic Brain Injury: A Randomized Clinical Trial.

To investigate the effects of an early neuromuscular electrical stimulation (NMES) protocol on muscle quality and size as well as signaling mediators of muscle growth and systemic inflammation in patients with traumatic brain injury (TBI). Two-arm, single-blinded, parallel-group, randomized, controlled trial with a blinded assessment. Setting. Trauma intensive care unit at a university hospital. Participants. Forty consecutive patients on mechanical ventilation (MV) secondary to TBI were prospectively recruited within the first 24 hours following admission. Interventions. The intervention group (NMES; n = 20) received a daily session of NMES on the rectus femoris muscle for five consecutive days (55 min/each session). The control group (n = 20) received usual care. Main Outcome Measures. Muscle echogenicity and thickness were evaluated by ultrasonography. A daily blood sample was collected to assess circulating levels of insulin-like growth factor I (IGF-I), inflammatory cytokines, and matrix metalloproteinases (MMP). Both groups were similar at baseline. A smaller change in muscle echogenicity and thickness (difference between Day 1 and Day 7) was found in the control group compared to the NMES group (29.9 ± 2.1 vs. 3.0 ± 1.2, p < 0.001; -0.79 ± 0.12 vs. -0.01 ± 0.06, p < 0.001, respectively). Circulating levels of IGF-I, pro-inflammatory cytokines (IFN-y), and MMP were similar between groups. An early NMES protocol can preserve muscle size and quality and maintain systemic levels of signaling mediators of muscle growth and inflammation in patients with TBI. This trial is registered with https://www.ensaiosclinicos.gov.br under number RBR-2db.

Acute effects of conventional versus wide-pulse neuromuscular electrical stimulation on quadriceps evoked torque and neuromuscular function.

The effectiveness of a neuromuscular electrical stimulation (NMES) program is proportional to the level of evoked torque, which can be achieved with either conventional or wide-pulse stimulations. The aim of this study was to compare evoked torque, objective fatigability, and related peripheral and central alterations, as well as changes in central nervous system (CNS) excitability induced by an acute session of conventional versus wide-pulse NMES. Seventeen young men underwent three 20-min NMES sessions: conventional (0.2 ms/50 Hz), wide-pulse at 50 Hz (1 ms/50 Hz), and wide-pulse at 100 Hz (1 ms/100 Hz). Neuromuscular measurements (i.e., maximal voluntary contraction, voluntary activation, evoked responses to femoral nerve stimulation, and CNS excitability) were performed on the right quadriceps femoris muscle before and after each NMES session. CNS excitability was measured using transcranial magnetic, thoracic, and transcutaneous spinal cord stimulations. The level of evoked torque was not significantly different between conventional and wide-pulse protocols applied at the maximal tolerable current intensity. All NMES protocols induced objective fatigability (~14% decrease in maximal voluntary contraction torque, p < 0.001) associated with peripheral (decrease in doublet torque and potentiated M-wave amplitude, p = 0.002 and p < 0.001, respectively) but not central (unchanged voluntary activation, p = 0.79) alterations. However, these acute changes did not differ between NMES protocols and none of the NMES protocols modified markers of CNS excitability. These results may allow to conjecture that chronic effects and treatment effectiveness could be comparable between conventional and wide-pulse NMES.

Can motor imagery balance the acute fatigue induced by neuromuscular electrical stimulation?

The combination of motor imagery (MI) and neuromuscular electrical stimulation (NMES) can increase the corticospinal excitability suggesting that such association could be efficient in motor performance improvement. However, differential effect has been reported at spinal level after MI and NMES alone. The purpose of this study was to investigate the acute effect on motor performance and spinal excitability following MI, NMES and combining MI and NMES. Ten participants were enrolled in three experimental sessions of MI, NMES and MI + NMES targeting plantar flexor muscles. Each session underwent 60 imagined, evoked (20% MVC) or imagined and evoked contractions simultaneously. Before, immediately after and 10min after each session, maximal M-wave and H-reflex were evoked by electrical nerve stimulation applied at rest and during maximal voluntary contraction (MVC). The MVC decreased significantly between PRE-POST (- 12.14 ± 6.12%) and PRE-POST 10 (- 8.1 ± 6.35%) for NMES session, while this decrease was significant only between PRE-POST 10 (- 7.16 ± 11.25%) for the MI + NMES session. No significant modulation of the MVC was observed after MI session. The ratio Hmax/Mmax was reduced immediately after NMES session only. The combination of MI to NMES seems to delay the onset of neuromuscular fatigue compared to NMES alone. This delay onset of neuromuscular fatigue was associated with specific modulation of the spinal excitability. These results suggested that MI could compensate the neuromuscular fatigue induced acutely by NMES until 10min after the combination of both modalities.

Comparative Study on the Effects of Surface Neuromuscular Electrical Stimulation Between Subjects With Unilateral Vocal Fold Paralysis in the Paramedian and Median Positions

<h2>Summary</h2> <b>Objectives</b>: To describe the impact of neuromuscular electrical stimulation (NMES) on two different types of unilateral vocal fold paralysis (UVFP): in the paramedian and median positions. <b>Methods:</b> Subjects underwent 12-minute-long sessions of NMES for 5 consecutive days (1 hour of intervention in total). A modified electrode placement was used to target the adductor muscles of the larynx. Acoustic, electroglottographic, imaging, auditory-perceptual, and self-perceived data were collected. <b>Results:</b> Apart from SPL, the results showed significant improvement in all vocal parameters for the subject with the paralyzed vocal fold in the paramedian position, but not for the subject with the paralyzed vocal fold in the median position. Both subjects demonstrated the activation of the cricothyroid muscles with the NMES application. They also reported no negative symptoms in the larynx or the presence of delayed onset muscle soreness postintervention. <b>Conclusions:</b> The results of this study support the use of NMES as an effective method for the treatment of UVFP in the paramedian position.

The effect of neuromuscular electrical stimulation on skin temperature in individuals with spinal cord injury: A prospective noncontrolled intervention study

Abstract The research on the effect of neuromuscular electrical stimulation (NMES) protocol on skin temperature (Tsk) in individuals with spinal cord injury (SCI) is a prospective non-controlled intervention study. 47 individuals with SCI were recruited from the outpatient clinic. NMES was applied to the tibial anterior (TA) muscles. Four assessments were performed: baseline, shortly after the end of NMES session (t0), 10 min after the end of NMES (t10) and 20 min after the end of NMES (t20). The intensity used was 1.5 mA RMS (root mean square) depending on the individuals. The variables were Tsk at forehead, dermatome C2 and L5 bilaterally. The dermatome C2 and forehead were measured only at baseline and t20. The measurement device was a noncontact infrared thermometer. Results of this study demonstrated that after NMES the stimulated dermatome (L5), showed an increase in local Tsk. In addition, the t20 showed that the Tsk did not drop to the baseline, being still significant in the analyzed group. The implications for rehabilitation practice and the positive effects of NMES are fundamental to improvement of the blood microcirculation and local metabolism.

Eletroestimulação e treinamento dos músculos do assoalho pélvico: efeito imediato após uma sessão

Abstract Introduction: Pelvic floor muscle training (PFMT) and neuromuscular electrical stimulation (NMES) are physiotherapeutic conservative treatments to prevent and to treat pelvic floor dysfunctions. Objective: To investigate the immediate effect of one session of PFMT versus NMES associated to pelvic floor muscle (PFM) contraction on the PFM function in nulliparous women. Methods: This is a cross-sectional experimental study. Twenty women were randomized into the “PFMT Group” and “NMES Group”. PFM function evaluation was performed by vaginal palpation and manometry before and after a single session. PFMT was composed by one series of eight sustained contractions of 6 seconds and one series of four fast contractions, in four different positions. NMES parameters were: biphasic pulsed current; frequency: 50 Hz; pulse duration: 0.7 ms; cycle on:off 4:8s; rise/decay: 2/2s, time: 20 minutes; and intensity: participant' sensibility. Data was analyzed by the ANOVA two-way for repeated measures to verify the difference between groups, within group and the interactions for PFM function. A 5% probability was considered in all tests. Results: There were no significant differences between groups. At intra-group analysis, there was a significant decrease in the maximal voluntary contraction (p = 0.01), by manometry, between pre- and post-session for both groups. Conclusion: The immediate effects of a single session of PFMT and NMES associated with voluntary PFM contraction are similar on PFM function, that is, no difference was found between groups.

Hemodynamic responses to neuromuscular electrical stimulation and to metaboreflex activation.

Metabolites produced during muscle exercise can sensitize types III and IV fibers, which account for increasing blood pressure (BP) and vascular resistance in non-exercising limbs, as well as for redistributing the blood flow to active muscles; reflex response is called metaboreflex. Neuromuscular electrical stimulation (NMES) induces greater local muscle metabolic demand than voluntary isometric contractions. Metabolic accumulation is essential to activate muscle metaboreflex; thus, the hypothesis of the current study is that one NMES session can induce metaboreflex with different hemodynamic responses in upper and lower limbs. Objective - to investigate whether one acute NMES session could activate metaboreflex by inducing different hemodynamic responses between arms and legs. Twenty (20) healthy subjects (mean age = 47.7±9.4 years, 13 women, mean body mass index = 26 ± 3 kg/m2) participated in this randomized crossover study. All participants were subjected to two NMES interventions, one in the upper limbs (UPL) and the other in the lower limbs (LL). Mean blood pressure (MBP), blood flow (BF) and vascular resistance (VR) were used to selectively evaluate metaboreflex responses at baseline, during NMES interventions, and recovery periods with, and without, postexercise circulatory occlusion (PECO+ and PECO-, respectively) through the area under the curve (AUC) in VR. MBP increased by 13% during UPL interventions and only remained high during PECO+. Changes in MBP were not observed in LL, although BF in the contralateral leg has decreased by 14% during PECO+ protocol. Muscle metaboreflex activation (AUC differences in VR between PECO+ and PECO-) was not different between UPL and LL (P=0.655). Acute NMES session has induced similar metaboreflex activation in both arms and legs, although hemodynamic responses differed between interventions.

Comparison of short-term training effects of two neuromuscular electrical stimulation modalities on muscle functions and mass

Purpose: The present study thus aimed to compare the effects of neuromuscular electrical stimulation (NMES) training, using alternating current (AC) and pulsed current (PC), on muscle function and muscle mass. Methods: Twenty-thee healthy male university students (age: 22.68 ± 3.7) were enrolled in this study and divided into two groups (AC = 12, PC = 11) to receive NMES training in both legs simultaneously. Each group underwent a 20-min NMES session using AC or PC, 2 days a week for 5 weeks. AC was delivered at 2.5 kHz (burst frequency: 75 Hz and pulse duration: 400 μs) for the knee extensors of both legs, and PC was delivered at 75 Hz (pulse duration: 400 μs), inducing 60 isometric contractions (on–off ratio: 5–15 s) at a knee joint angle of 100° (0° = full extension). Muscle strength, power, and mass were assessed 1 week before and 1 and 6 weeks after the training program. Results: Findings show a significant increase in vertical jump height after both NMES training, although no torque gain was detected regardless of the type of modality. A significant increase in the region fat-free mass (trained legs) in both NMES currents without a difference between them was observed in the function of the trained muscles. Conclusion: Short-term training (5 weeks) using AC or PC could be insufficient to detect an improvement in muscle functions such as torque gain. However, the short-term training using AC may improve physical performance and body composition.

Early neuromuscular electrical stimulation reduces the loss of muscle mass in critically ill patients - A within subject randomized controlled trial.

To investigate the effect of Neuromuscular Electrical Stimulation (NMES) on muscle thickness, strength and morphological and molecular markers of the quadriceps. Adult critically ill patients with an expected prolonged stay received unilateral quadriceps NMES sessions for 7 consecutive days. Before and after the intervention period, quadriceps thickness was measured with ultrasound. After the intervention period, strength was assessed in cooperative patients and muscle biopsies were taken. Multivariable regression was performed to identify factors affecting muscle thickness loss. Muscle thickness decreased less in the stimulated leg (-6±16% versus -12±15%, p=0.014, n=47). Strength was comparable. Opioid administration, minimal muscle contraction and more muscle thickness loss in the non-stimulated muscle were independently associated with better muscle thickness preservation. Stimulated muscles showed a shift towards larger myofibers and higher MyHC-I gene expression. NMES did not affect gene expression of other myofibrillary proteins, MuRF-1 or atrogin-1. Signs of myofiber necrosis and inflammation were comparable for both muscles. NMES attenuated the loss of muscle mass, but not of strength, in critically ill patients. Preservation of muscle mass was more likely in patients receiving opioids, patients with a minimal muscle contraction during NMES and patients more prone to lose muscle mass. clinicaltrials.govNCT02133300.

Assessing Discomfort Levels During Facial Neuromuscular Electrical Stimulation Using Discomfort Level Scale: A Preliminary Study.

The primary aim of the current study was to evaluate discomfort levels of facial NMES in healthy volunteers. Eight participants completed the Discomfort Level Scale (DLS) following each motor level facial neuromuscular electrical stimulation (NMES) session. Each participant completed 12 sessions of facial NMES for a total of 96 NMES treatments. Pearson product-moment correlation coefficient demonstrated a significant correlation between the facial NMES intensity level and DLS (p < 0.001). This study demonstrated that the DLS is a useful tool to check for discomfort levels in patients who receive facial NMES. Further, this study provides strong support for the tolerability of facial NMES.

Effects of concomitant neuromuscular electrical stimulation during repetitive transcranial magnetic stimulation before repetitive facilitation exercise on the hemiparetic hand.

Repetitive transcranial magnetic stimulation (rTMS) and Repetitive facilitative exercise (RFE) improves motor impairment after stroke. To investigate whether neuromuscular electrical stimulation (NMES) can facilitate the effects of rTMS and RFE on the function of the hemiparetic hand in stroke patients. This randomized double-blinded crossover study divided 20 patients with hemiparesis into two groups and provided treatment for 4 weeks at 5 days/week. NMES-before-sham group and NMES-following-sham group performed NMES sessions and sham NMES sessions for each 2 weeks. Patients received NMES or sham NMES for the affected extensor muscle concurrently with 1 Hz rTMS for the unaffected motor cortex for 10 min and performed RFE for 60 min. The Fugl-Meyer Assessment (FMA), Action Research Arm Test (ARAT), Box and Block Test (BBT) and Modified Ashworth Scale (MAS) were used for evaluation. FMA and ARAT improved significantly during both sessions. The gains in the BBT during an NMES session were significantly greater than those during a sham NMES session. MAS for the wrist and finger significantly decreased only during an NMES session. NMES combined with rTMS might facilitate, at least in part, the beneficial effects of RFE on motor function and spasticity of the affected upper limb.

Muscle alterations induced by electrostimulation are lower at short quadriceps femoris length

This study aimed at determining through MRI investigations, force and soreness assessments whether the modulation of muscle length is a relevant strategy for minimising neuromuscular electrical stimulation (NMES)-induced muscle damage in young healthy participants. Comparison of 2 NMES sessions (40 isometric electrically-evoked contractions of the knee extensors) was randomly performed on 1 knee flexed at 50° (short muscle length) and the contralateral at 100° (long muscle length) in a single group of healthy participants. Indirect markers of muscle damage including changes in maximal voluntary isometriccontraction (MVC) force, muscle volume and transverse relaxation time (T2) were measured before, 2days (D2), 4days (D4) and 7days (D7) after the NMES sessions in each limb of the ten participants. Although stimulation intensity was similar during the NMES session on both limbs, significantly lower force production was recorded at long muscle length (peak at 30 ± 5% MVC force) as compared to short muscle length (peak at 61 ± 12% MVC force). In the following days, MVC force at long muscle length was decreased from D2 to D7, whereas no significant changeoccurred at short muscle length. Increases in muscle volume and T2 were found at each time point in stimulated muscles at long muscle length, whereas no change was found at short muscle length. For the same stimulation intensity, NMES-induced isometric contractions generate higher knee extension force output and result in lower muscle tissues alterations that could be related to a lower intramuscular shear strain when exercise is performed at short muscle length.

The effect of low level laser irradiation on oxidative stress, muscle damage and function following neuromuscular electrical stimulation. A double blind, randomised, crossover trial

BackgroundLow level laser therapy (LLLT) is among novel methods for preventing and treating muscle damage and soreness induced by volitional exercise, but little is known about using LLLT before neuromuscular electrical stimulation. The aim of this first randomised, double blind, crossover trial addressing this issue was to evaluate effects of LLLT on muscle damage and oxidative stress, as well as recovery of muscle function after a single session of isometric neuromuscular electrical stimulation(NMES).MethodsTwenty four moderately active, healthy men aged 21–22 years received 45 electrically evoked tetanic, isometric contractions of the quadriceps femoris, preceded by LLLT or sham-LLLT. Maximal isometric voluntary muscle torques, perceived soreness, and blood samples were analysed from baseline to 96 h post intervention. We measured plasma markers of muscle damage (the activity of creatine kinase), and inflammation (C-reactive protein), and evaluated redox state parameters.ResultsNMES-evoked contractions induced oxidative stress, demonstrated by an increase in lipid peroxidation and impairments in enzymatic antioxidant system. LLLT irradiations had a protective effect on NMES-induced decrease in enzymatic antioxidant defence and shortened the duration of inflammation. This effect of irradiations on redox state and inflammation did not affect lipid peroxidation, muscle damage, and muscle torque.ConclusionsLLLT may protect from impairments in enzymatic antioxidant system and may shorten inflammation induced by a single NMES session in moderately active, healthy men. However, the effects of LLLT on redox state and inflammatory processes do not seem to affect muscle damage and recovery of muscle function after NMES.Trial registrationThe study was retrospectively registered in the Australian New Zealand Clinical Trials Registry (ANZCTR); The trial registration number: ACTRN12619000678190; date of registration: 6 May 2019.

Impact of mild-to-moderate exacerbations on outcomes of neuromuscular electrical stimulation (NMES) in patients with COPD.

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are common among patients attending pulmonary rehabilitation (PR) and may compromise its outcomes. Neuromuscular electrical stimulation (NMES) seems one of the few exercise modalities that can actually be continued during AECOPD, due to its low burden on the impaired respiratory and cardiovascular system. However, the quality of evidence is low. The purpose of this study was to assess the impact of mild-to-moderate AECOPD on adherence/outcomes of a high-frequency (HF) or low-frequency (LF) NMES training program, as part of inpatient PR, in severely dyspneic, weakened individuals with COPD. 62 patients who received NMES as the sole supervised muscle training modality during an 8-week PR program (HF-NMES: n=33; LF-NMES: n=29) were analyzed retrospectively. 48.4% experienced ≥1 AECOPD during PR and were classified as exacerbators. Exacerbators completed 75 NMES sessions (interquartile range: 73-78) and were able to increase training intensity with 24mA (15-39), while non-exacerbators completed 76 sessions (73-79) and increased training intensity with 35mA (22-50), with no between-group differences (p=0.474 and p=0.065, respectively). The median change in 6-min walking distance, cycle endurance time, and isokinetic quadriceps strength and endurance did not differ between the exacerbation and non-exacerbation group. To conclude, the occurrence of mild-to-moderate AECOPD during a PR program primarily focused on NMES, does not affect adherence, intensity, and clinical outcomes in patients with severe COPD. Continuing NMES seems a feasible way to potentially counteract exacerbation-related lower-limb muscle dysfunction and improve outcomes of PR, with HF-NMES being the preferential muscle training modality.