Multimodal and conventional resistance training interventions improve muscle function in older adults: Findings from the Training IMCT study.

Age-associated remodeling processes affect the intramuscular connective tissue (IMCT) network, which may significantly impair muscle function. Thus, we aimed to test whether including exercises shown to efficiently target the IMCT to a conventional resistance exercise intervention (CONV) would result in greater functional gains as compared to CONV alone. Fifty-three men and women (66.2 ± 3.3 years) were assigned to either CONV (n = 15), multimodal training (MULTI; n = 17) or a control (CTRL; n = 21) group. All subjects were tested at baseline, and those assigned to CONV or MULTI underwent a 16-week training intervention. The CONV group followed a progressive resistance training program, in which the number of weekly training sessions gradually increased from 1 to 3. In the MULTI group, one of these sessions was replaced with plyometric training, followed by self-myofascial release. Testing included maximal strength and power, imaging-based muscle volume, architecture, and functional performance. The intervention effects were analyzed using two- or three-way repeated measures ANOVA models (α = 0.05). Briefly, the maximal knee extension isometric contraction, one-repetition maximum, and isokinetic peak torque increased in all groups (p < 0.05), albeit to a lesser extent in CTRL. On the other hand, quadriceps femoris muscle volume (p = 0.019) and vastus lateralis pennation angle (p < 0.001) increased only in the MULTI group. Handgrip strength did not change in response to the intervention (p = 0.312), whereas Sit-to-Stand performance improved in all groups after the first 8-wks, but only in MULTI and CONV after 16-wks (all p < 0.001). In conclusion, we found that a resistance training intervention in which one weekly training session is replaced by plyometric training is feasible and as effective as a program consisting solely of conventional strength training sessions for inducing gains in muscle strength and function in older adults. Muscle size and architecture improved only in the MULTI group. German Clinical Trials: DRKS00015750.

Effects of 12 weeks of neuromuscular electrical stimulation of the quadriceps muscles on the function and physio-biochemical traits in functionally fit female nursing-home residents aged 75 + years: a pilot study.

PURPOSE: Muscular changes induced by neuromuscular electrical stimulation (NMES) are well recognized, but knowledge of how NMES influences the physio-biochemical traits of the oldest old is still limited. This study investigated the effect of NMES applied for 12 weeks to the quadriceps muscles of female nursing-home residents aged 75 + on their functional capability and inflammatory, bone metabolism, and cardiovascular traits. METHODS: Nineteen women regularly taking part in two body conditioning sessions per week were randomized into an electrical stimulation group (ES; n = 10; 30 min sessions, 3 times per week) or a control group (CON; n = 9). At baseline and study week 12, all women performed the 30 s chair stand test (30sCST), the 6-minute walk test (6MWT), and the instrumented timed up and go test (iTUG). Resting heart rates, blood pressure, and the blood concentrations of inflammatory and bone metabolism markers were also measured twice. RESULTS: NMES increased the strength of participants' quadriceps muscles and their performance on the 30sCST and 6MWT while lowering resting arterial blood pressure and inflammatory marker levels; osteoclast activity showed a tendency to decrease. Changes in the iTUG results were not observed. A multiple regression analysis found that the results of functional tests in the ES group were best correlated with pulse pressure (the 30sCST and iTUG tests) and diastolic blood pressure (the 6MWT test). CONCLUSION: Twelve weeks of NMES treatment improved participants' functional capacity and inflammatory, bone metabolism, and cardiovascular traits. The ES group participants' performance on functional tests was best predicted by hemodynamic parameters.

The Effects of 2 Different Soft Tissue Mobilization Techniques on Delayed Onset Muscle Soreness in Male Recreational Athletes: A Single-Blinded Randomized Controlled Trial.

CONTEXT: Soft tissue mobilization is frequently employed for delayed onset muscle soreness (DOMS) management. Foam roller and percussive massage are 2 popular soft tissue mobilization methods preferred by various professionals. However, their effects on DOMS symptoms are controversial and there are no studies comparing these 2 methods. The aim of the present study was to compare the acute effects of soft tissue mobilization with a foam roller or a percussive massage device on DOMS in young male recreational athletes. DESIGN: A parallel, single-blinded, randomized controlled trial. METHODS: Thirty-six participants (median [interquartile range 25/75]; age: 20.0 [19.3/21.0] y) were randomly allocated to percussive massage group (n = 12), foam roller group (n = 12), and control group (n = 12). First, a fatigue protocol targeting quadriceps femoris was performed. Then, participants received soft tissue mobilization with foam roller/percussive massage or rested for 10 minutes according to their groups. Pain and fatigue were evaluated by a visual analog scale, and the skin surface temperature of over the quadriceps femoris was measured with thermal camera imaging. Evaluations were performed at baseline, following fatigue protocol, at 24th hour, and at 48th hour. Changes from the baseline at 24th and 48th hours were compared between groups. RESULTS: No significant between-group differences were observed at the assessments performed at 24th or 48th hour regarding the changes from baseline in pain (P value for 24th hour = .905, P value for 48th hour = .733), fatigue (P value for 24th hour = .895, P value for 48th hour = .606), or skin surface temperature measurements (P values for 24th hour = between .300 and .925, P values for 48th hour = between .311 and .750). CONCLUSIONS: Soft tissue mobilizations applied with foam roller or percussive massage device do not seem to be superior to passive resting in alleviating DOMS symptoms in recreational athletes.

Peripheral fatigue regulation during knee extensor exercise in type 1 diabetes and consequences on the force-duration relationship.

PURPOSE: This study aimed to examine if peripheral fatigue is adjusted during knee extensor (KE) exercise in order not to surpass a critical threshold patient with type 1 diabetes (T1D) and the consequences of this mechanism on the force-duration relationship. METHODS: Eleven T1D individuals randomly performed two different sessions in which they performed 60 maximum voluntary contractions (MVC; 3 s contraction, 2 s relaxation). One trial was performed in the non-fatigued state (CTRL) and another after fatiguing neuromuscular stimulation of the KE (FNMES). Peripheral and central fatigue were quantified by the difference between pre and post exercise in quadriceps voluntary activation (ΔVA) and potentiated twitch (ΔPtw). Critical torque (CT) was determined as the average force of the last 12 contractions, whereas W' was calculated as the area above the CT. RESULTS: Although FNMES led to a significant decrease in potentiated twitch (Ptw) before performing the 60-MVCs protocol (p < 0.05), ΔVA (∼ -7.5%), ΔPtw (∼ -39%), and CT (∼816 N) post-MVCs were similar between the two conditions. The difference in W' between CTRL and FNMES was correlated with the level of pre-fatigue induced in FNMES (r2 = 0.60). In addition, W' was correlated with ΔPtw (r2 = 0.62) in the CTRL session. CONCLUSION: Correlative results in the present study indicate that regulating peripheral fatigue mechanisms at a critical threshold limit W'. Additionally, peripheral fatigue during KE exercise is limited to an individual threshold in T1D patients.

Who's Afraid of Electrical Stimulation? Let's Revisit the Application of NMES at the Knee.

BACKGROUND: Restoring quadriceps strength is essential for successful rehabilitation of knee injuries, but many athletes return to their previous activity with persisting muscle weakness. Strong evidence supports using neuromuscular electrical stimulation (NMES) to improve quadriceps strength; however, there is a lack of widespread clinical implementation. We believe there is a critical need to provide clinical approaches that promote using NMES to improve patients' quadriceps strength and ensuring clinicians provide high-value rehabilitation care. CLINICAL QUESTION: What is best practice when using NMES to facilitate strength after injury, what are barriers to its use, and how can they be addressed? KEY RESULTS: We discuss the low clinical implementation of NMES, perceived barriers to using NMES, and provide recommendations for setup and dosage parameters for effective use of NMES. CLINICAL APPLICATION: We aim for this commentary, with accompanying videos, to serve as a resource for clinicians who are using commercially available NMES units in clinical practice. J Orthop Sports Phys Ther 2024;54(2):1-6. Epub 31 October 2023. doi:10.2519/jospt.2023.12028.

Pulsed Red and Blue Photobiomodulation for the Treatment of Thigh Contusions and Soft Tissue Injury: A Randomized Controlled Trial.

CONTEXT: Contusion and soft tissue injuries are common in sports. Photobiomodultion, light and laser therapy, is an effective aid to increase healing rates and improve function after various injury mechanisms. However, it is unclear how well photobiomodulation improves function after a contusion soft tissue injury. This study aimed to determine the effects of a pulsed red and blue photobiomodulation light patch on muscle function following a human thigh contusion injury. DESIGN: Single-blinded randomized control trial design. METHODS: We enrolled 46 healthy participants. Participants completed 5 visits on consecutive days. On the first visit, participants completed a baseline isokinetic quadriceps strength testing protocol at 60°/s and 180°/s. On the second visit, participants were struck in the rectus femoris of the anterior thigh with a tennis ball from a serving machine. Immediately following, participants were treated for 30 minutes with an active or placebo photobiomodulation patch (CareWear light patch system, CareWear Corp). Following the treatment, participants completed the same isokinetic quadriceps strength testing protocol. Participants completed the treatment and isokinetic quadriceps strength test during the following daily visits. We normalized the data by calculating the percent change from baseline. We used a mixed model analysis of covariance, with sex as a covariate, to determine the difference between treatment groups throughout the acute recovery process. RESULTS: We found the active photobiomodulation treatment significantly increased over the placebo group, quadriceps peak torque during the 180°/s test (P = .030), and average power during both the 60°/s (P = .041) and 180°/s (P ≤ .001) assessments. The mean peak torque and average power of 180°/s, at day 4, exceeded the baseline levels by 8.9% and 16.8%, respectively. CONCLUSIONS: The red and blue photobiomodulation light patch improved muscle strength and power during the acute healing phase of a human thigh contusion injury model.

Lower limb muscle activation pattern in male soccer players with lumbar hyperlordosis.

OBJECTIVE: the aim of the current study was to compare the lower limb muscle activation pattern in soccer players with and without lumbar hyperlordosis during single-leg squat performance. METHODS: thirty male collegiate soccer players (15 with and 15 without lumbar hyperlordosis) performed the SLS task. Surface EMG was used to record the activation of eleven lower limb muscles. The activation of these muscles reduces to 100 points during the SLS cycle, where 50% demonstrates the maximum knee flexion, and 0% and 99% demonstrate the maximum knee extension. RESULTS: soccer players with lumbar hyperlordosis had higher muscle activation than those with normal lumbar lordosis in gluteus maximus, biceps femoris, and medial gastrocnemius. By contrast, they had lower gluteus medius, vastus medialis oblique, rectus femoris, soleus, and medial gastrocnemius (only in the final ascent phase of the SLS) muscle activity than the normal group during the SLS. CONCLUSION: this alteration may negatively affect targeted muscle performance during the SLS. Subsequent study is required to specify whether such an alteration in the lower limb muscle could be accompanied by injury in soccer players and change in their athletic performance.

Dry Needling for Arthrogenic Muscle Inhibition of Quadriceps Femoris in Patients after Reconstruction of Anterior Cruciate Ligament: a Protocol for a Randomized Controlled Trial.

Background: : Dry needling (DN) is recommended as a therapeutic modality for various neuromusculoskeletal disorders. No study has been performed on the impact of DN on arthrogenic muscle inhibition (AMI) after anterior cruciate ligament reconstruction (ACLR). This study protocol is aimed to investigate the impacts of DN on AMI of quadriceps femoris, corticomotor, and spinal reflex excitability in patients with ACLR. Methods: : A double-blind, between-subject, randomized, controlled trial will be conducted to measure changes in AMI after DN. Twenty-four subjects with ACLR will be recruited to receive a DN or a sham DN, providing that they met the inclusion criteria. Three sessions of DN on the quadriceps femoris will be applied during a one-week period. The primary outcome measures are the active motor threshold, motor evoked potential, and Hmax - Mmax ratio. The secondary outcomes are the International Knee Documentation Committee subjective knee form questionnaire score and maximum quadriceps isometric torque. Data will be collected at baseline, immediately after the first session, after the third session, and at the one-month follow-up visit. Discussion: : The results of this study will provide preliminary evidence regarding the effects of DN on AMI of quadriceps femoris in patients with ACLR.

Wearable Neuromuscular Electrical Stimulation on Quadriceps Muscle Can Increase Venous Flow.

Neuromuscular electrical stimulation (NMES) of the quadriceps (Q) may increase venous blood flow to reduce the risk of venous thromboembolism. This study assessed whether Q-NMES pants could increase peak venous velocity (PVV) in the femoral vein using Doppler ultrasound and minimize discomfort. On 15 healthy subjects, Q-NMES using textile electrodes integrated in pants was applied with increasing intensity (mA) until the first visible muscle contraction [measurement level (ML)-I] and with an additional increase of six NMES levels (ML II). Discomfort using a numeric rating scale (NRS, 0-10) and PVV were used to assess different NMES parameters: frequency (1, 36, 66 Hz), ramp-up/-down time (RUD) (0, 1 s), plateau time (1.5, 4, and 6 s), and on:off duty cycle (1:1, 1:2, 1:3, 1:4). Q-NMES pants significantly increased PVV from baseline with 93% at ML I and 173% at ML II. Frequencies 36 Hz and 66 Hz and no RUD resulted in significantly higher PVV at both MLs compared to 1 Hz and 1 s RUD, respectively. Plateau time, and duty cycle did not significantly change PVV. Discomfort was only significantly higher with increasing intensity and frequency. Q-NMES pants produces intensity-dependent 2-3-fold increases of venous blood flow with minimal discomfort. The superior NMES parameters were a frequency of 36 Hz, 0 s RUD, and intensity at ML II. Textile-based NMES wearables are promising for non-episodic venous thromboembolism prevention.

Changes in Muscle Mass and Strength During Follow-Up After One-Year Resistance Training Interventions in Older Adults.

ABSTRACT: Mertz, KH, Reitelseder, S, Rasmussen, MA, Bülow, J, Højfeldt, G, Jensen, M, Hjulmand, M, Lindberg, J, Kramer, MU, Bechshøft, R, and Holm, L. Changes in muscle mass and strength during follow-up after one-year resistance training interventions in older adults. J Strength Cond Res 37(10): 2064-2070, 2023-The aim of this study was to investigate if home-based resistance training compared with center-based resistance training was associated with better preservation of muscle mass and strength in older individuals, 6 months after the interventions ended. One hundred four healthy older individuals (>65 years) who had completed 1 year of either home-based light-intensity training with daily whey protein supplementation (LITW), center-based heavy resistance training with whey protein supplementation (HRTW), or daily whey protein supplementation alone (WHEY) returned for follow-up measurement 6 months after the interventions. Measures of muscle mass, strength, and power were assessed at the end of intervention as well as at follow-up. Furthermore, we compared changes in these parameters between subjects who continued resistance training (≥1 weekly training session) during follow-up (CONT) with those who stopped (STOP). Resistance training continuation during follow-up did not differ between HRTW and LITW (41 vs. 41%, P = 1.0) but was higher for both groups compared with WHEY (18%, P = 0.04-0.05). However, no between-group differences were observed between LITW/HRTW/WHEY in changes in muscle mass, strength, or power during follow-up. STOP was associated with a poorer preservation of quadriceps cross-sectional area compared with CONT (-1.7 cm 2 [-0.4 to -3.0], P = 0.01, effect size: 0.79). No effect of training continuation was observed on changes in muscle strength and power. In conclusion, maintenance of muscle mass and strength is not superior after home-based resistance training compared with center-based training. However, training continuation seems crucial for the maintenance of muscle mass, irrespective of the training intervention.

Effects of foam rolling and strength training on post exercise hypotension in normotensive women: A cross-over study.

Foam rolling (FR) has recently become very popular among athletes and recreational exercisers and is often used during warm up prior to strength training (ST) to induce self-myofascial release. The purpose was to examine the acute effects of ST and FR performed in isolation or in combination on blood pressure (BP) responses during recovery in normotensive women. Sixteen normotensive and strength trained women completed four interventions: 1) rest control (CON), 2) ST only, 3) FR only, and 4) ST immediately followed by FR (ST + FR). ST consisted of three sets of bench press, back squat, front pull-down, and leg press exercises at 80% of 10RM. FR was applied unilaterally in two sets of 120 s to each of the quadriceps, hamstring, and calf regions. Systolic (SBP) and diastolic (DBP) BP were measured before (rest) and every 10 min, for 60 min, following (Post 10-60) each intervention. Cohen's d effect sizes were calculated to indicate the magnitude effect by the formula d = Md/Sd, where Md is the mean difference and Sd is the standard deviation of differences. Cohen's d effect-sizes were defined as small (≥0.2), medium (≥0.5), and large (≥0.8). There were significant reductions in SBP for ST at Post-50 (p < 0.001; d = -2.14) and Post-60 (p < 0.001; d = -4.43), for FR at Post-60 (p = 0.020; d = -2.14), and for ST + FR at Post-50 (p = 0.001; d = -2.03) and Post-60 (p < 0.001; d = -2.38). No change in DBP was observed. The current findings suggest that ST and FR performed in isolation can acutely reduce SBP but without an additive effect. Thus, ST and FR can both be used to acutely reduce SBP and, importantly, FR can be added to a ST regimen without furthering the SBP reduction during recovery.

Effects of eccentric-emphasized leg curl intervention on muscle strength imbalance markers in professional soccer players during pre-season.

BACKGROUND: The effects of strength training on muscle strength imbalance are unclear in professional soccer players. As a result, this study examined the effects of an 8-week strength training program comprising eccentric-emphasized prone leg curl adjusted according to the individual strength imbalance status. METHODS: Ten professional soccer players (26.0 ± 3.6 yrs) participated in the study. Players who had a ≥ 10% contralateral imbalance in knee flexors eccentric peak torque (n = 6) performed two additional repetitions per set in the low-strength limb (high-volume, HV) compared to the high-strength limb (low-volume, LV). Isokinetic concentric knee extension and concentric and eccentric knee flexion peak torque (PT) and derived contralateral imbalances and conventional and functional hamstring-to-quadriceps ratios (H:Q) were assessed at baseline and after 8 weeks. Differences at baseline were assessed using paired-sample T-tests, and a two-way (limb x time) repeated measures analysis of covariance (ANCOVA) for changes over time. RESULTS: A significant improvement in the eccentric knee flexion PT was observed in both limbs after 8 weeks (P < 0.05), with greater effects observed in the HV limb (25.0 N m, 95% CI: 15.1-34.9 N m). Significant decreases were also observed in the contralateral imbalances from concentric knee extension and flexion and eccentric knee flexion PT (P < 0.05). Differences were not observed in concentric knee extension and flexion PT (P > 0.05). CONCLUSIONS: A short-term eccentric-emphasized leg curl intervention adjusted by the initial knee flexors eccentric strength was an efficient method to improve knee flexors strength imbalance in professional soccer players.

[Effect of dietary supplements and whey protein on muscle mass and strength of the operated limb after anterior cruciate ligament reconstruction: a systematic review].

Muscle weakness and atrophy of the quadriceps muscle after anterior cruciate ligament reconstruction may persist for up to 6 months after surgery and cause re-injury to the ipsilateral or contralateral limbs. Many authors state that adequate nutritional status during the rehabilitation period can contribute to faster postoperative recovery of muscle mass and strength of the lower limb, be an adjunct to exercise, or serve an alternative treatment strategy. The purpose of the research was to conduct a systematic review of the literature and evaluate the degree of influence of dietary supplements on muscle mass and strength of the operated limb after reconstruction of the anterior cruciate ligament (ACL). Material and methods. The search for articles was carried out in international databases PubMed, Google Scholar, Cochrane Library. The time frame of the search was 22 years. To be included in the review, studies had to meet the PICOS criteria: participants were men and women over 18 years of age after ACL reconstruction; intervention - supplementation after and/or before and after ACL reconstruction; comparison - placebo group or no supplementary interventions; results - assessment of the dynamics of changes in muscle mass (cross-sectional area, muscle thickness or size of skeletal muscle fibers) and / or maximum strength (dynamic or isometric) of the operated limb; research design - randomized controlled trials (RCT). The quality of selected RCTs was assessed using the Cochrane Collaboration Risk of Bias (RoB 2) tool. Results. A total of 1397 articles were found after searching in the databases. This systematic review included 6 RCTs with a total number of patients 186. The following dietary supplements were used: leucine - 1 article, glucosam ine - 1 article, creatine - 1 article, vitamins E and C - 2 articles. One study evaluated the effect of whey protein supplementation in combination with neuromuscular electrical stimulation on isometric strength of the operated limb. When comparing the data of 3 groups in the pre- and postoperative periods, there were no statistically significant differences between the groups. When considering the protocols for taking dietary supplements based on creatine, glucosamine, vitamins E and C, none of the studies demonstrated statistically significant improvements in the parameters of maximum strength or muscle hypertrophy of the operated limb in the main groups compared with the control groups. Also, no results have been obtained indicating that these dietary supplements can slow down muscl e atrophy after surgery. In another study that evaluated the effect of leucine supplementation, by the end of the rehabilitation program, the muscle strength of the operated limb tended to increase more in the leucine group than in the placebo group, but without a statistically significant difference. At 10 cm from the patella, the femoral circumference of the operated limb in the leucine group increased more than in the placebo group, and the differences were statistically significant (р=0.009). Two studies were rated as high risk of bias, three as moderate risk, and one as low risk. Conclusion. None of the supplements used had a statistically significant effect on the muscle strength of the operated limb after ACL reconstru ction. In terms of thigh muscle hypertrophy, the only significant improvement was associated with leucine supplementation and an increase in thigh circumference at a distance of 10 cm from the patella.

Effects of Sprint Interval and Endurance Respiratory Muscle Training on Postcycling Inspiratory and Quadriceps Fatigue.

PURPOSE: We investigated whether a 4-wk period of respiratory muscle endurance training (RMET) or respiratory muscle sprint interval training (RMSIT) would lead to an attenuation of inspiratory muscle and quadriceps fatigue after a bout of high-intensity cycling compared with a placebo intervention (PLAT), as predicted by the respiratory metaboreflex model. METHODS: Thirty-three active, young healthy adults performed RMET, RMSIT, or PLAT. Changes in inspiratory muscle and quadriceps twitches in response to a cycling test at 90% of peak work capacity were assessed before and after training. EMG activity and deoxyhemoglobin (HHb, via near-infrared spectroscopy) of the quadriceps and inspiratory muscles were also monitored during the cycling test, along with cardiorespiratory and perceptual variables. RESULTS: At pretraining, cycling reduced the twitch force of the inspiratory muscles (86% ± 11% baseline) and quadriceps (66% ± 16% baseline). Training did not attenuate the drop in twitch force of the inspiratory muscles (PLAT, -3.5 ± 4.9 percent-points [p.p.]; RMET, 2.7 ± 11.3 p.p.; RMSIT, 4.1 ± 8.5 p.p.; group-training interaction, P = 0.394) or quadriceps (PLAT, 3.8 ± 18.6 p.p.; RMET, -2.6 ± 14.0 p.p.; RMSIT, 5.2 ± 9.8 p.p.; group-training interaction P = 0.432). EMG activity and HHb levels during cycling did not change after training for either group. Only RMSIT showed a within-group decrease in the perception of respiratory exertion with training. CONCLUSIONS: Four weeks of RMET or RMSIT did not attenuate the development of exercise-induced inspiratory or quadriceps fatigue. The ergogenic effects of respiratory muscle training during whole-body exercise might be related to an attenuation of perceptual responses.

Wide-pulse electrical stimulation of the quadriceps allows greater maximal evocable torque than conventional stimulation.

PURPOSE: The effectiveness of a neuromuscular electrical stimulation (NMES) program has been shown to be proportional to the maximal evocable torque (MET), which is potentially influenced by pulse characteristics such as duration and frequency. The aim of this study was to compare MET between conventional and wide-pulse NMES at two different frequencies. METHODS: MET-expressed as a percentage of maximal voluntary contraction (MVC) torque-and maximal tolerable current intensity were quantified on 71 healthy subjects. The right quadriceps was stimulated with three NMES protocols using different pulse duration/frequency combinations: conventional NMES (0.2 ms/50 Hz; CONV), wide-pulse NMES at 50 Hz (1 ms/50 Hz; WP50) and wide-pulse NMES at 100 Hz (1 ms/100 Hz; WP100). The proportion of subjects reaching the maximal stimulator output (100 mA) before attaining maximal tolerable current intensity was also quantified. RESULTS: The proportion of subjects attaining maximal stimulator output was higher for CONV than WP50 and WP100 (p < 0.001). In subjects who did not attain maximal stimulator output in any protocol, MET was higher for both WP50 and WP100 than for CONV (p < 0.001). Maximal tolerable current intensity was lower for both WP50 and WP100 than for CONV and was also lower for WP100 than for WP50 (p < 0.001). CONCLUSION: When compared to conventional NMES, wide-pulse protocols resulted in greater MET and lower maximal tolerable current intensity. Overall, this may lead to better NMES training/rehabilitation effectiveness and less practical issues associated with maximal stimulator output limitations.

Effect of electromyostimulation training on intramuscular fat accumulation determined by ultrasonography in older adults.

PURPOSE: Electromyostimulation (EMS) induces a short-term change in muscle metabolism, and EMS training induces long-term improvements of muscle atrophy and function. However, the effects of EMS training on intramuscular fat in older adults are still poorly known. The purpose of this study was to examine whether the intramuscular fat index and biochemical parameters change with EMS training of the quadriceps femoris muscles in older adults. METHODS: Nineteen non-obese older men and women performed EMS training of the quadriceps femoris for 12 weeks (3 times/week; single session for 30 min). The intramuscular fat content index was estimated by echo intensity of the vastus lateralis and rectus femoris muscles on ultrasonography, and muscle thickness was also measured. Muscle strength was assessed as the maximal voluntary contraction during isometric knee extension. Echo intensity, muscle thickness, and muscle strength were measured before and after EMS training. A rested/fasting blood samples were collected before and after EMS training for measuring plasma glucose, insulin, free fatty acid, triglyceride, and interleukin-6 concentrations. To examine the acute effect of a single-EMS session on biochemical parameters, blood samples were taken before and after the EMS session. RESULTS: EMS training did not significantly change echo intensity in muscles, muscle thickness, muscle strength, or biochemical parameters. Regarding the acute effect on blood lipid concentrations, a single-EMS session increased free fatty acid and glucose concentrations. CONCLUSION: EMS sessions had an acute effect of increasing free fatty acid and glucose concentrations, but EMS training intervention did not improve intramuscular fat content.

Acute effects of electrostimulation and blood flow restriction on muscle thickness and fatigue in the lower body.

Neuromuscular electrical stimulation (NMES) in combination with blood flow restriction (BFR) enhances muscle hypertrophy and force-generating capacity. The present study aimed to investigate the acute effects of BFR and NMES, both in isolation and in combination, on muscle thickness (MT) and fatigue in the lower body of 20 young healthy subjects. Different stimuli were applied for 25 min, defined by the combination of BFR with high- and low-frequency NMES, and also isolated BFR or NMES. Changes in MT were then evaluated by ultrasound of the rectus femoris (RF) and vastus lateralis (VL) muscles at the end of the session (POST) and 15 min later (POST 15'). Lower limb fatigue was evaluated indirectly by strength performance. Results showed that RF MT was higher under the combined protocol (BFR + NMES) or isolated BFR than under NMES - regardless of the frequency - both at POST (p ≤ 0.018) and POST 15' (p ≤ 0.016). No significant changes in MT were observed under isolated NMES or BFR at POST 15' when compared with basal values (p ≥ 0.067). No significant differences were observed for VL MT between conditions (p = 0.322) or for fatigue between conditions (p ≥ 0.258). Our results indicate that a combination of BFR and NMES acutely increases MT in sedentary subjects. Also, although not significantly, BFR conditions had a greater tendency to induce fatigue than isolated NMES.HighlightsThe combination of blood flow restriction (BFR) and neuromuscular electrical stimulation (NMES) produces higher acute cell swelling than the isolated application of either NMES or BFR.BFR in isolation appears to produce greater cell swelling than NMES, regardless of the frequency used.BFR conditions had a greater tendency to induce fatigue than isolated NMES.

Post-operative electrical muscle stimulation attenuates loss of muscle mass and function following major abdominal surgery in older adults: a split body randomised control trial.

INTRODUCTION: Significant losses of muscle mass and function occur after major abdominal surgery. Neuromuscular electrical stimulation (NMES) has been shown to reduce muscle atrophy in some patient groups, but evidence in post-operative patients is limited. This study assesses the efficacy of NMES for attenuating muscle atrophy and functional declines following major abdominal surgery in older adults. METHODS: Fifteen patients undergoing open colorectal resection completed a split body randomised control trial. Patients' lower limbs were randomised to control (CON) or NMES (STIM). The STIM limb underwent 15 minutes of quadriceps NMES twice daily on post-operative days (PODs) 1-4. Ultrasound measurements of Vastus Lateralis cross-sectional area (CSA) and muscle thickness (MT) were made preoperatively and on POD 5, as was dynamometry to determine knee extensor strength (KES). Change in CSA was the primary outcome. All outcomes were statistically analysed using linear mixed models. RESULTS: NMES significantly reduced the loss of CSA (-2.52 versus -9.16%, P < 0.001), MT (-2.76 versus -8.145, P = 0.001) and KES (-10.35 versus -19.69%, P = 0.03) compared to CON. No adverse events occurred, and patients reported that NMES caused minimal or no discomfort and felt that ~90-minutes of NMES daily would be tolerable. DISCUSSION: NMES reduces losses of muscle mass and function following major abdominal surgery, and as such, may be the promising tool for post-operative recovery. This is important in preventing long-term post-operative dependency, especially in the increasingly frail older patients undergoing major abdominal surgery. Further studies should establish the efficacy of bilateral NMES for improving patient-centred outcomes.

Oral ketone monoester supplementation does not accelerate recovery of muscle force or modulate circulating cytokine concentrations after muscle-damaging eccentric exercise in healthy males and females.

NEW FINDINGS: What is the central question of this study? Does acute ketone monoester supplementation enhance the recovery of muscle force and modulate circulating cytokine concentrations after muscle-damaging eccentric exercise? What is the main finding and its importance? Ketone monoester supplementation increased plasma ß-hydroxybutyrate concentrations but did not attenuate the reduction in muscle force or the increase in plasma inflammatory cytokine concentrations that occurred after eccentric exercise. Notably we report novel data demonstrating a reduction in plasma TRAIL concentrations after eccentric exercise, highlighting TRAIL signalling as a possibly novel regulator of muscle recovery. ABSTRACT: Muscle-damaging eccentric exercise is associated with inflammation and impaired muscle force. ß-Hydroxybutyrate (ß-OHB) reduces muscle protein breakdown during inflammation but whether oral ketone monoester supplementation accelerates recovery of muscle force after eccentric exercise is unknown. Sixteen healthy males and females consumed thrice daily ketone monoester (27 g per dose; n = 8; six females; KES) or isocaloric maltodextrin placebo (n = 8; four females; PLA) drinks (randomized, double-blind, parallel group design) for 3 days beginning immediately after 300 unilateral eccentric quadriceps contractions during complete eucaloric dietary control (1.2 ± 0.1 g/kg BM/day standardized protein). Bilateral muscle force measurements and venous blood sampling were performed before and 3, 6, 24, 48 and 72 h after eccentric exercise. Plasma ß-OHB concentrations were greater in KES compared with PLA at 3 h (0.56 ± 0.13 vs. 0.22 ± 0.04 mM, respectively; P = 0.080) and 6 h (0.65 ± 0.41 vs. 0.23 ± 0.02 mM, respectively; P = 0.031) post-eccentric exercise. Relative to the control leg, isokinetic work (by 20 ± 21% in PLA and 21 ± 19% in KES; P = 0.008) and isometric torque (by 23 ± 13% in PLA and 20 ± 18% in KES; P < 0.001) decreased from baseline at 3 h in the eccentrically exercised leg, and remained below baseline at 48 and 72 h, with no significant group differences. Of eight measured plasma cytokines, interleukin-6 (P = 0.008) and monocyte chemoattractant protein-1 (P = 0.024) concentrations increased after 6 h, whereas tumour necrosis factor-related apoptosis-inducing ligand concentrations decreased after 3 h (P = 0.022) and 6 h (P = 0.011) post-exercise with no significant group differences. Oral ketone monoester supplementation elevates plasma ß-OHB concentrations but does not prevent the decline in muscle force or alter plasma inflammatory cytokine profiles induced by eccentric exercise.

Efficacy of Patellar Taping and Electromyographic Biofeedback Training at Various Knee Angles on Quadriceps Strength and Functional Performance in Young Adult Male Athletes with Patellofemoral Pain Syndrome: A Randomized Controlled Trial.

Background: The severity of the articular lesion is the single most essential element in investigating the extent of flexion that is required for activities. However, a prior study found no differences in muscle strength gains of quadriceps muscles at different knee angles in people with patellofemoral pain syndrome (PFPS). Objective: The effects of patellar taping and electromyographic biofeedback (EMG-BF)-guided isometric quadriceps strengthening at different knee angles (e.g., 30°, 60°, and 90° of knee flexion) on quadriceps strength and functional performance in people with PFPS were compared in this single-blind randomized controlled parallel trial. Methods: Sixty adult male athletes with PFPS (age: 26.9 ± 1.4 years) were randomly divided into two groups. The experimental group (n = 30) received patellar taping and EMG-BF-guided isometric contraction exercise at 30°, 60°, and 90° angles, and the control group (n = 30) received sham patellar taping without EMG-BF-guided exercises for six weeks. Pain intensity, knee function, muscle strength, and the single-leg triple hop (SLTH) test were assessed. Results: The pain intensity and SLTH scores between the groups were significantly different at the end of the trial (p ≤ 0.001). The EMG-BF and control groups had mean pain scores of 1.3 (0.8) and 4.5 (0.8), respectively. The EMG-BF and control groups had mean functional scores of 80.4 (5.1) and 69.1 (6.1), respectively. The mean SLTH score for the EMG-BF group was 540.7 (51.2) and for the control group it was 509.4 (49.8) after the trial. Quadriceps muscle strength was significantly higher in those who performed quadriceps strength training at 60° of knee flexion after six weeks than in those who performed strength training at 30° or 90° of knee flexion. Conclusion: The findings indicated that individuals who trained their quadriceps at a 60° knee angle had significantly stronger quadriceps muscles than individuals who trained at 30° or 90° of knee flexion. Trial Registration. This trial is registered at Clinical Trials.gov under the identifier NCT05055284.