Elbow Flexion Exercise Research Articles

The impact of blood flow restricted electrical stimulations on recovery from muscle damage.

Both electrical stimulations (E-STIM) and blood flow restriction (BFR) have been shown to treat symptoms of exercise-induced muscle damage, but little is known about their combined effects which was the purpose of this study. Individuals completed one set of eccentric elbow flexion exercises to induce muscle damage. Forty-eight hours later, E-STIM was applied using an interferential current administered to both arms for 20 min; however, only one arm completed the E-STIM protocol while also undergoing repeated bouts of BFR (full occlusion for 2 min separated by a 1-min rest intervals). Discomfort and isometric strength were assessed immediately before the damaging exercise, immediately before the treatments, and 0, 10, and 30 min posttreatment. A total of 22 individuals (11 females) completed the study. There were no interactions with respect to discomfort (BF10 = 0.008) or isometric strength (BF10 = 0.009) indicating that the addition of BFR did not alter the effectiveness of E-STIM. There was a main effect of time indicating that the damaging exercise was successful at depressing torque (pre: 284 N, post: 199 N; BF10 = 2.70e9) and inducing discomfort (pre: 0 au, post: 6.4 au; BF10 = 3.21e17). While isometric strength did not recover with the E-STIM treatments, discomfort was reduced at each the immediate post (5.3 au; BF10 = 56 294) 10-min post (5.0 au; BF10 = 46 163), and 30-min post (4.9 au; BF10 = 707 600) time points. E-STIM may be useful for treating discomfort, but does not appear capable of recovering strength associated with muscle damage. The efficacy of E-STIM would not appear to be enhanced if performed under BFR.

A study on brain neuronal activation based on the load in upper limb exercise (STROBE).

This study aimed to determine the level of brain activation in separate regions, including the lobes, cerebellum, and limbic system, depending on the weight of an object during elbow flexion and extension exercise using functional magnetic resonance imaging (fMRI). The study was conducted on ten male undergraduates (22.4 ± 1.2 years). The functional images of the brain were obtained using the 3T MRI. The participants performed upper limb flexion and extension exercise at a constant speed and as the weight of the object for lifting was varied (0 g and 1000 g). The experiment consisted of four blocks that constituted 8 minutes. Each block was designed to comprise a rest phase (1 minute) and a lifting phase (1 minute). The results showed that, in the parietal lobe, the activation was higher for the 0 g-motion condition than for the 1000 g-motion condition; however, in the occipital lobe, cerebellum, sub-lobar, and limbic system, the activation was higher for the 1000 g-motion condition than for the 0 g-motion condition. The brain region for the perception of object weight was identified as the ventral area (occipital, temporal, and frontal lobe), and the activation of the ventral pathway is suggested to have increased as the object came into vision and as its shape, size, and weight were perceived. For holding an object in hand, compared to not holding it, the exercise load was greater for controlling the motion to maintain the posture (arm angle at 90°), controlling the speed to repeat the motion at a constant speed, and producing an accurate posing. Therefore, to maintain such varied conditions, the activation level increased in the regions associated with control and regulation through the motion coordination from vision to arm movements (control of muscles). A characteristic reduced activation was observed in the regions associated with visuo-vestibular interaction and voluntary movement when the exercise involved lifting a 1000-g object compared to the exercise without object lifting.

Development of an EMG-based Elbow- Exoskeleton with Twisted String Actuation

Abstract This paper presents an exoskeleton for upper extremity rehabilitation of stroke patients. In order to make rehabilitation widely available, the goal is an inexpensive, portable, and easy-to-use therapy for paralysis of the arm. The exoskeleton is actuated by twisted string actuators (TSA). To reduce the length of the TSA a motor with hollow shaft was chosen, as this allows the string to run through the motor. The control of the exoskeleton is designed for predefined elbow flexion exercises. The start of the movement is triggered by a threshold value in the sEMG of the m. biceps brachii. To evaluate the controller, the exoskeleton performed a flexion movement (5° to 115°) in 2 s and then an extension back to 5° in the same time after a 1 s wait. To simulate different force requirements, additional weights up to 1500 g were attached. During both, the flexion and extension movement, that angle tracking error was sufficiently small and the steady state error was zero. The angular velocity of the elbow joint showed pronounced oscillations with increasing weights. The results show that TSAs can be used to actuate elbow exoskeletons. Thus lightweight, ergonomic, simple and small rehabilitation devices can now be built on this basis. The elasticity of the system must be considered in future work. sEMG must be further implemented to control more sophisticated functions of the rehabilitation device.

The Effects Of High Load And Low Load Unilateral Bicep Training On Changes In Post-activation Performance Enhancement

Post-activation performance enhancement (PAPE) represents the short-term improvement in muscle performance following a conditioning stimulus. Previous research has shown that PAPE is enhanced following high-load training. Since PAPE represents a local response, we hypothesize that this effect might provide insight into changes at the muscle level, which might influence strength adaptations. To test this, we compared PAPE following two training protocols known to produce differences in maximal strength. PURPOSE: To determine if PAPE is augmented to a greater extent following high load training compared to low load training. METHODS: 13 participants (3 males) were randomly assigned to a group completing high-load exercise with their dominant arm, and low-load exercise with their non-dominant arm. This is part of a larger ongoing study, which is why conditions were not counter-balanced based on dominancy. The high load training consisted of performing a 1RM test (five attempts maximum), followed by 4 sets of traditional exercise (~8-12 repetitions). The low-load condition completed 4 sets of exercise, aiming for ~30-40 repetitions. 18 sessions of elbow flexion exercise were completed over six weeks. PAPE was measured before and after training using isokinetic dynamometry at 210 deg/sec. PAPE testing began with a warm-up, the pre-conditioning torque attempt, the 6 s isometric conditioning stimulus, followed by the post-conditioning torque attempt 3 minutes later. There were two hypotheses: H0: differences would be equal or H1: greater following training (specifically high load training in comparison across conditions). Hypotheses were tested using Bayes Factors for Informative Hypotheses (BAIN). RESULTS: PAPE was not greater following six weeks of high-load (Pre Δ: 1.6 Nm vs. Post Δ: 0.26 Nm, BF01: 11.2) or low-load (Pre Δ: 0.33 Nm vs. Post Δ: -0.32 Nm, BF01: 5.6) resistance training. The available data suggests that each condition changed similarly across time (difference of -0.7 Nm, BF01: 5.4). CONCLUSIONS: Preliminary data suggests that high load, as well as low load, training for six weeks does not result in an improvement in PAPE, when performing unilateral bicep exercise. As such, high load training does not appear to be superior to low load training for improved PAPE responses.

The impact of postexercise blood flow restriction on local muscle endurance of a remote limb.

Studies have examined the influence of postexercise blood flow restriction as a mechanism to activate muscle afferents and assess nonlocal muscle fatigue. Althoughthese studies have assessed fatigue during maximal contractions, less is known about how these afferents may impact submaximal local muscle endurance, which was the purpose of the present study. Individuals completed two testing visits which involved completing a set of elbow flexion exercises to volitional failure on the nondominant followed by the dominant arm. During both trials, a pneumatic cuff was placed at the top of the nondominant arm before exercise. This cuff was inflated to either 0% (control) or 70% (experimental) of the individual's arterial occlusion pressure immediately after the set was completed. We then evaluated how this impacted local muscle endurance of the dominant arm using a Bayesian paired samples t-test with an uninformed prior width of 0.707 centred on 0. A total of 36 individuals completed the study (18 females). There was a greater discomfort present in the experimental trial when compared to the control trial (control: 4.5 standard deviation [SD]: 2.4); experimental: 5.8 [SD: 1.9]; BF10 = 61.46), but there were no differences in repetitions completed on the dominant arm (control: 43 [SD: 9], experimental: 43 [SD: 10]; BF10 = 0.179). Applying blood flow restriction postexercise induced sensations of discomfort but did not alter the local muscle endurance of the contralateral limb. These results suggest that increasing the activation of muscle afferents does not appear to alter the submaximal muscle endurance of a remote limb.

Research on the Effect of MT+FES Training on Sensorimotor Cortex.

Purpose Aiming at the motor recovery of patients with unilateral upper limb motor dysfunction after stroke, we propose a mirror therapy (MT) training method, which uses surface electromyography (sEMG) to identify movements on one side and control the other side to perform functional electrical stimulation (FES) while mirror therapy is used. And we verify the effect of this training method by analyzing the activity changes of the sensorimotor cortex. Method Ten subjects (6 men and 4 women) were randomly divided into two groups according to 3 men and 2 women in each group: the experimental group (n = 5) received FES+MT training, and the control group (n = 5) received MT training. Both groups were trained at a fixed time at 9 : 00 am every day, each time lasting 20 minutes, once a day, 5 days a week, continuous training for 4 weeks, and the training action was elbow flexion training. During the training of the elbow flexion exercise, the experimental group applied FES with a frequency of 30 Hz, a pulse width of 100 μs, and a current of 10 mA to the muscles corresponding to the elbow flexion exercise, and rested for 10 s after 10-s stimulation. We collect the EEG of the elbow flexion motor imagery of all subjects before and after training, and calculate the eigenvalue E, and analyze the effect of FES+MT training on the activity of the cerebral sensorimotor cortex. Results After repeated measure (RM) two-way ANOVA of the two groups, comparing the subjects' μ rhythm elbow flexion motor imagery eigenvalue E, the experimental group (after training) > the control group (after training) > before training. Conclusion The FES+MT training method has obvious activation effect on the cerebral sensorimotor cortex.

The Effects of Resistance Training on Architecture and Volume of the Upper Extremity Muscles: A Systematic Review of Randomised Controlled Trials and Meta-Analyses

To systematically review the effects of exercise on fascicle geometry and muscle size parameters of the upper extremity muscles, the CENTRAL, CINAHL, PubMed and OpenGrey databases were searched on 31 July 2021. Finally, 17 randomised controlled trials (RCTs) were included in this systematic review. High-intensity bench press training (g = 1.03) and 12 RM bench press exercises (g = 1.21) showed a large effect size on increasing pectoralis major muscle size. In the elbow extensors, large effects were reported for an increase in muscle size with isometric maximal voluntary co-contraction training (g = 1.97), lying triceps extension exercise (g = 1.25), and nonlinear periodised resistance training (g = 2.07). In addition, further large effects were achieved in the elbow flexors via traditional elbow flexion exercises (g = 0.93), concentric low-load forearm flexion-extension training (g = 0.94, g = 1), isometric maximal voluntary co-contraction training (g = 1.01), concentric low-load forearm flexion-extension training with blood flow restriction (g = 1.02, g = 1.07), and nonlinear periodised resistance training (g = 1.13, g = 1.34). Regarding the forearm muscles, isometric ulnar deviation training showed a large effect (g = 2.22) on increasing the flexor carpi ulnaris and radialis muscle size. Results show that these training modalities are suitable for gaining hypertrophy in the relevant muscles with at least four weeks of training duration. Future RCTs should investigate the effects of exercise modalities on the triceps brachii fascicle geometry, the infraspinatus muscle thickness (MT) and the subscapular MT due to their associations with sports performance.

Acute Influence of Leg Press Exercise on Hamstring Muscles Functional Stress

Four different situations of the stress of the previous hamstring muscles were induced by the combination of the LP, Knee Flexor (KF), Stiff (ST) and Elbow Flexion (EF) exercises, to measure the level of reduction of the hamstring muscles functional capacity after each exercise and compares them to the LP. The procedures consisted of performing the KF exercise 10s after the execution of the EF, and KF 10s after the execution of the ST, and KF 10s after the execution of the KF itself, and FJ 10 s after the execution of the LP.

Photobiomodulation Therapy at 808 nm Does Not Improve Biceps Brachii Performance to Exhaustion and Delayed-Onset Muscle Soreness in Young Adult Women: A Randomized, Controlled, Crossover Trial.

ObjectiveThis study aims to investigate the effects of laser photobiomodulation (PBM) at 808 nm on biceps brachii performance to exhaustion, rating of perceived exertion (RPE), and delayed onset muscle soreness (DOMS) in untrained young women.MethodsThirteen young women (20.1 ± 2.9 years) participated in a crossover study in which they received, in a counterbalanced manner, active and placebo laser PBM on two occasions (T1 and T2), separated by a 7-day washout period. During T1 and T2, participants received active (100 mW output power, irradiance of 35.7 W cm–2, and total energy of 28 J/arm) or placebo laser irradiation on the biceps brachii muscle at 20 min before the repetitions-to-failure test [six sets at 60% of one-repetition maximum (1RM) until failure] for elbow flexion exercise. The number of repetitions performed and RPE over the six sets, as well as DOMS from basal up to 72 h after the repetitions-to-failure test, were recorded.ResultsThere was a significant (time, p < 0.05) reduction in the number of repetitions performed and an increase in RPE over six sets, with no statistical differences between placebo and active laser conditions (treatment × time, p > 0.05). DOMS increased at 24 h postexercise and progressively returned to baseline after 72 h in both conditions (time, p < 0.05; treatment × time, p > 0.05).ConclusionOur results indicate that acute laser PBM at 808 nm does not improve biceps brachii performance to exhaustion, RPE, and DOMS in untrained women.

Ipsilateral Lower-to-Upper Limb Cross-Transfer Effect on Muscle Strength, Mechanical Power, and Lean Tissue Mass after Accentuated Eccentric Loading.

Background and Objectives: To investigate the effects of unilateral accentuated eccentric loading (AEL) on changes in lean mass and function of leg trained (TL) and ipsilateral non-trained arm (NTA) in young men and women. Materials and Methods: In a prospective trial, 69 Physically active university students (20.2 ± 2.2 years) were randomly placed into a training group (n = 46; 27 men, 19 women) or a control group without training (n = 23; 13 men, 10 women). Participants in the training group performed unilateral AEL in the leg press exercise of the dominant leg twice a week for 10 weeks. An electric motor device-generated isotonic resistance at different intensities for both concentric (30% of 1-RM) and eccentric contractions (105% of 1-RM). Changes in thigh and arm lean tissue mass, unilateral leg press and unilateral elbow flexion maximal concentric (1-RM) and isometric strength (MVIC), and unilateral muscle power at 40, 60, and 80% 1-RM for both leg press and elbow flexion exercises before and after intervention were compared between groups, between sexes and between TL and NTA. Results: Both men and women in the training group showed increases (p < 0.05) in lean tissue mass, 1-RM, MVIC, and muscle power for TL. In NTA, 1-RM, MVIC, and muscle power increased without significant differences between sexes, but neither in men nor women changes in lean tissue mass were observed. In addition, men showed greater changes in TL, but changes in NTA were similar between sexes. No gains in any variable were found for the control group. Conclusions: AEL protocol produced similar neuromuscular changes in TL and ipsilateral NTA, which suggests that strong ipsilateral lower-to-upper limb cross-transfer effects were induced by the eccentric-overload training. However, early ipsilateral increases in muscle force and power were not associated with lean mass gains. Both men and women experienced similar changes in NTA; however, men showed greater changes in TL.

A Retrospective Analysis to Determine Whether Training-Induced Changes in Muscle Thickness Mediate Changes in Muscle Strength.

To investigate the role of muscle thickness changes on changes in strength following 6weeks of unaccustomed resistance training, via retrospective analysis. 151 participants completed 6weeks of no intervention (CONTROL), one-repetition maximum training (1RM-TRAIN), or traditional resistance training (TRAD-TRAIN). Groups were assigned by covariate adaptive randomization. 1RM-TRAIN and TRAD-TRAIN performed elbow flexion exercise on the dominant arm 3 times/week. One-repetition maximum strength and muscle thickness (B-mode ultrasound at 50, 60, and 70% of the anterior upper arm) were assessed pre- and post-training. Direct and indirect effects on strength via each training modality were quantified relative to CONTROL using indicator-coded, change-score mediation analyses for each muscle thickness site. Values are presented as regression coefficients (95% CI). The effect of 1RM-TRAIN on muscle thickness was greater than CONTROL for 60% [0.09 (0.01, 0.17) cm] and 70% [0.09 (0.01,0.18) cm] models. All muscle thickness changes for TRAD-TRAIN were greater than CONTROL: 50% [0.24 (0.16, 0.33) cm], 60% [0.25 (0.17, 0.33) cm], 70% [0.23 (0.14, 0.32) cm]. All direct effects on strength were greater for 1RM-TRAIN versus CONTROL: 50% [1.90 (1.21, 2.58) kg], 60% [1.89 (1.19, 2.58) kg], 70% [1.81 (1.12, 2.51) kg]; and TRAD-TRAIN versus CONTROL: 50% [2.04 (1.29, 2.80) kg], 60% [1.98 (1.22, 2.75) kg], 70% [1.79 (1.05, 2.53) kg]. Compared to CONTROL, there was no indication of an effect of 1RM-TRAIN on strength through muscle thickness (i.e., indirect effect) for 50% [- 0.03 (- 0.17, 0.10)], 60% [- 0.01 (- 0.17, 0.17)], or 70% [0.07 (- 0.09, 0.28)] sites, nor of TRAD-TRAIN for 50% [- 0.11 (- 0.48,0.29)], 60% [- 0.04 (- 0.42, 0.40)], and 70% sites [0.17 (-0.23,0.58)]. Training-induced changes in muscle thickness do not appear to appreciably mediate training-induced changes in the strength of untrained individuals during the first 6weeks of training.

Research on the mechanism of elbow flexion based on AnyBody

In order to analyze the dynamic characteristics of the upper limbs including the musculoskeletal system in elbow flexion, a human upper limb movement model including the musculoskeletal system was established based on the biomechanical analysis software AnyBody, and the overall model was subjected to inverse dynamics simulation and muscle force analysis to obtain the human body Muscle strength and muscle activity of upper limb muscle groups during elbow flexion exercise. Taking the human biceps as an example for analysis, the muscle strength of the biceps during elbow flexion exercise was obtained. When the loaded load is within a reasonable range, the muscle force will change regularly with the increase and decrease of the load, indicating that the training effect of flexion exercise needs to control the loading load within a certain range, which provides scientific theoretical support for upper limb muscle rehabilitation training.

Distinction of Students and Expert Therapists Based on Therapeutic Motions on a Robotic Device Using Support Vector Machine

PurposeTo clarify the feature values of exercise therapy that can differentiate students and expert therapists and use this information as a reference for exercise therapy education.MethodsThe participants were therapists with 5 or more years of clinical experience and 4th year students at occupational therapist training schools who had completed their clinical practices. The exercise therapy task included Samothrace (code name, SAMO) exercises implemented on the elbow joint based on the elbow flexion angle, angular velocity, and exercise interval recordings. For analyses and student/therapist comparisons, the peak flexion angle, peak velocity, and movement time were calculated using data on elbow angle changes acquired via SAMO. Subsequently, bootstrap data were generated to differentiate between the exercise therapy techniques adopted by therapists and students, and a support vector machine was used to generate four types of data combinations with the peak flexion angle, peak velocity, and movement time values. These data were used to estimate and compare the respective accuracies with the Friedman test.ResultsThe peak flexion angles were significantly smaller in the case of students. Furthermore, the peak velocities were larger, the peak flexion angles were smaller, and the movement times were shorter compared with those of therapists. The combination of peak velocity and peak flexion angle yielded the highest diagnostic accuracies.ConclusionWhen students and therapists performed upper limb exercise therapy techniques based on the kinematics movement of a robot arm, the movement speeds and joint angles differed. The combination of peak velocity and peak flexion angle was the most effective classifier used for the differentiation of the abilities of students and therapists. The peak velocity and peak flexion angle of the therapist group can be used as a reference for students when they learn upper limb therapeutic exercise techniques.

Reproducibility and reliability of performance indicators to evaluate the therapeutic effectiveness of biofeedback therapy after elbow surgery: An observational case series.

Electromyographic biofeedback (EMG-BF) therapy provides information on the state of contraction of the targeted muscles and relaxation of their antagonists, which can facilitate early active range of motion (RoM) after elbow surgery. Our aim in this study was to calculate the minimum detectable change (MDC) during EMG-BF therapy, initiated in the early postoperative period after elbow surgery.This study is an observational case series. EMG-BF of muscle contraction and relaxation was provided during active elbow flexion and extension exercises. Patients completed 3 sets of 10 trials each of flexion and extension over 4 weeks. The total range of flexion-extension motion and scores on the Japanese Society for Surgery of the Hand version of the disability of the arm, shoulder, and hand questionnaire and the Japanese version of the Patient-Rated Elbow Evaluation were obtained at baseline and weekly during the 4-week intervention period. A prediction formula was developed from the time-series data obtained during the intervention period, using the least-squares method. The estimated value was calculated by removing the slope from the prediction formula and adding the initial scores to residuals between the measured scores and predicted scores individually. Systematic error, MDC at the 95th percentile cutoff (MDC95), repeatability of the measures, and the change from the baseline to each time-point of intervention were assessed.The MDC95 was obtained for all 3 outcome measures and the range of values was as follows: RoM, 8.3° to 22.5°; Japanese version of the Patient-Rated Elbow Evaluation score, 17.6 to 30.6 points; and disability of the arm, shoulder, and hand questionnaire subscale: disability and symptoms score, 14.2 to 22.9 points.The efficacy of EMG-BF after elbow surgery was reflected in earlier initiation of elbow RoM after surgery and improvement in patient-reported upper limb function scores. The calculated MDC95 cut-offs could be used as reference values to assess the therapeutic effects of EMG-BF in individuals.

Blood Flow Restriction Exercise: Effects of Sex, Cuff Width, and Cuff Pressure on Perceived Lower Body Discomfort.

Narrow cuffs cause less discomfort than wide cuffs immediately following elbow flexion exercise in combination with blood flow restriction, possibly due to a balling up effect of the bicep underneath the cuff. In this study, we sought to examine the impact of cuff width, sex, and pressure on perceived discomfort in the quadriceps, following knee extensions. One hundred participants completed three separate experiments. In Experiment 1, we compared participants' discomfort at rest after using a 5 and a 12 cm cuff. In Experiment 2, we compared the discomfort from these two cuffs after four sets of exercise. In Experiment 3, we used the same exercise protocol as in Experiment 2, but we compared the discomfort between a 12 cm cuff inflated to an inappropriate pressure and a 12 cm cuff inflated to the recommended pressure. We found no sex differences in Experiments 1 and 3. In Experiment 1, the narrow cuff had higher discomfort (16 vs 12 AU). In Experiment 2, men reported higher discomfort than women, with no discomfort differences related to cuff width, though narrow cuffs were most preferred. In Experiment 3, cuffs inflated to a pressure intended for narrow cuffs were associated with higher discomfort, and participants preferred to use it less. In summary, we found no strong evidence for discomfort differences due to cuff width. There was some indication that participants preferred narrow cuffs with pressures inflated to the recommended relative pressure. Muscle shape may influence how cuff width affects discomfort.

Assessing True Variability And Mean Changes To Two Distinct Resistance Training Protocols

Millions of dollars are spent analyzing inter-individual differences in response to resistance exercise, but the lack of a non-exercise control group makes it possible that these studies may simply be examining random error. Furthermore, it has been hypothesized that the magnitude of variability may differ depending upon the exercise protocol employed, but this yet to be appropriately tested. PURPOSE: To determine differences in two distinct resistance training protocols and whether true variability could be detected after accounting for random error. METHODS: Individuals (n=151) were randomly assigned to one of three groups: (1) a traditional exercise group performing four sets of elbow flexion exercise to failure; (2) a one-repetition maximum (1RM) performing a 1RM elbow flexion test; and (3) a time-matched non-exercise control group. Both exercise groups performed 18 sessions over six weeks. A Bayesian ANCOVA was used to test for mean changes across groups while adjusting for pre-values. To assess whether the variability in response to each exercise intervention differed from that of the control group, Bayesian Levene’s tests were computed. Bayes Factors (BF10) were used to quantify evidence for or against the null hypothesis. RESULTS: Both 1RM (2.3kg; BF10 = 4.791e+6) and traditional training groups (2.4kg; BF10 = 11,915) increased 1RM strength similarly (BF10 = 0.21), but only the 1RM group increased untrained arm 1RM strength (1.5kg; BF10 = 271). Only the traditional exercise group increased ultrasound measured muscle thickness (~0.23 cm across all sites; all BF10 ≥ 224). Across both training groups, the only differential responses were found in the change in 1RM strength of the trained arm in the traditional training group (BF10 = 5.381). This resulted in a true variability of 1.8 kg after the removal of random error. CONCLUSION: These findings demonstrate the importance of taking into consideration the magnitude of random error when determining response heterogeneity, as many studies may be classifying individuals based on random error. Additionally, our mean results demonstrate that strength is largely driven by task specificity, and the cross-over effect of strength may be load dependent.

Acute Cardiovascular And Muscular Response To No-load Exercise With And Without Blood Flow Restriction

PURPOSE: To examine acute changes in muscle thickness, isometric strength, and arterial occlusion pressure (AOP) following NO LOAD exercise with and without the application of blood flow restriction (BFR) in the upper body. METHODS: Changes in muscle thickness, isometric strength and AOP were examined following four sets of twenty repetitions of unilateral elbow flexion exercise. Participants performed maximal muscle contractions with no external load throughout a full range of motion with and without the application of a moderate BFR (40% of AOP). Results are displayed as mean (SD). RESULTS: 39 resistance-trained males and females completed the study. For isometric torque there was a condition x time interaction (p = 0.012). The BFR condition had lower isometric torque immediately following exercise [56.07 (17.78) Nm] compared to the control group [58.67 (19.06) Nm]. In addition, both the BFR and control conditions demonstrated a decrease in torque immediately following exercise [mean change = 4.5 (4.5) and 1.82 (4.5) Nm for BFR and control conditions respectively], which remained decreased below baseline 15 minutes post exercise [mean change 2.39 (5.5) and 2.28 (3.19) Nm for BFR and control conditions respectively]. For muscle thickness, there was a main effect for time (p < 0.001). Muscle thickness increased from pre [3.52 (.78) cm] to post [3.68 (.81) cm] exercise and remained increased above baseline 15 min post exercise [3.6 (.80) cm]. For AOP, there was a group x time interaction (p = 0.027). The change in AOP was greater in the BFR group [16.6 (13.42) mmHg] compared to the control group [11.1 (11.84) mmHg]. CONCLUSIONS: NO LOAD exercise with the application of BFR led to greater reductions in isometric torque compared to NO LOAD exercise without the application of BFR. In addition, the application of BFR led to an exaggerated cardiovascular response compared to NO LOAD exercise alone. There were no differences in acute muscle swelling between NO LOAD exercise with and without BFR. These results suggest that the application of BFR to NO LOAD exercise may lead to a greater level of muscle fatigue when performing four sets of twenty maximal repetitions. This is accompanied with an exaggerated cardiovascular response.

Blood Pressure Increase in Hypertensive Individuals During Resistance Training Protocols With Equated Work to Rest Ratio.

Introduction: Despite growing evidence regarding the benefits of resistance training in hypertension, the large and abrupt rise of systolic blood pressure (SBP) observed during resistance exercise execution has resulted in concern about its safety. However, the manipulation of the resistance training protocol (RTP) organization, maintaining the work to rest ratio equated between protocols (W:R-equated), may reduce the SBP increase.Purpose: To compare cardiovascular responses during two W:R-equated RTPs (3 × 15:88 s vs. 9 × 5:22 s – sets × reps: rest between sets) performed in exercises for the lower and upper limbs.Methods: Twelve medicated hypertensives (48 ± 8 years) randomly performed two RTPs in the bilateral leg extension (BLE) and unilateral elbow flexion (UEF) exercises at 50% 1RM. Increases (Δ) of SBP, heart rate (HR) and rate pressure product (RPP) during the exercises were measured by photoplethysmography.Results: In both BLE and UEF exercises, Δ SBP was significantly greater during 3 × 15:88 s than 9 × 5:22 s (peak values: BLE = + 84 ± 39 vs. + 67 ± 20 mm Hg, and UEF = + 46 ± 25 vs. + 37 ± 18 mm Hg, respectively, both p < 0.05). ΔHR and ΔRPP were significantly higher in the 3 × 15:88 s than 9 × 5:22 s in BLE (peak values + 45 ± 17 vs. + 30 ± 8 bpm, and + 15,559 ± 5570 vs. + 10,483 ± 2614 mm Hg. bpm).Conclusion: In medicated hypertensives, a RTP combining more sets with less repetitions per set and shorter rest intervals between sets (i.e., 9 × 5:22 s) produced a smaller increase in cardiovascular load (ΔSBP, ΔHR and ΔRPP) during its execution than a protocol with fewer longer sets (i.e., 3 × 15:88 s).

Resistance training with blood flow restriction: Impact on the muscle strength and body composition in people living with HIV/AIDS

The aim of the study was to compare the impact of 12-week resistance training with blood flow restriction (GRTBFR) versus, traditional resistance training (GTRT) and non-training on the muscle strength and body composition HIV/AIDS participants. Muscle strength was tested at baseline, and on the 6th, 21st and 36th training sessions, using maximal repetition test. Pre- and post-intervention body composition changes were measured by dual-energy X-ray absorptiometry. Resistance training was undertaken three times a week comprising bilateral elbow extension and flexion exercises, unilateral flexion and bilateral knee extension. Changes in strength and body composition (pre- and post-intervention) between groups were evaluated by mixed models of repeated measures, and by paired and unpaired comparisons, considering the Effect Size. All groups were similar at baseline for muscle strength and body composition. Post-intervention, the training groups showed similar, statistically significant increases in muscle strength (GRTBFR=25.7–57.4%; GTRT=24.5–52.3%) and skeletal muscle tissue (GRTBFR=8.4%; GTRT=8.3%). There was also a significant change in body fat (p=0.023–0.043), with significant effect sizes for strength and skeletal muscle tissue (0.41–2.27), respectively. These results suggest that both resistance training interventions promoted muscle hypertrophy, body fat reduction and positive impact on muscle strength in people living with HIV/AIDS. Resistance training with blood flow restriction proved to be an effective alternative to include patients with marked physical weakness, unable to engage in regular strength training programme. ClinicalTrials.gov identifier: NCT02783417.

Embedded Bio-Mimetic System for Functional Electrical Stimulation Controlled by Event-Driven sEMG.

The analysis of the surface ElectroMyoGraphic (sEMG) signal for controlling the Functional Electrical Stimulation (FES) therapy is being widely accepted as an active rehabilitation technique for the restoration of neuro-muscular disorders. Portability and real-time functionalities are major concerns, and, among others, two correlated challenges are the development of an embedded system and the implementation of lightweight signal processing approaches. In this respect, the event-driven nature of the Average Threshold Crossing (ATC) technique, considering its high correlation with the muscle force and the sparsity of its representation, could be an optimal solution. In this paper we present an embedded ATC-FES control system equipped with a multi-platform software featuring an easy-to-use Graphical User Interface (GUI). The system has been first characterized and validated by analyzing CPU and memory usage in different operating conditions, as well as measuring the system latency (fulfilling the real-time requirements with a 140 ms FES definition process). We also confirmed system effectiveness, testing it on 11 healthy subjects: The similarity between the voluntary movement and the stimulate one has been evaluated, computing the cross-correlation coefficient between the angular signals acquired during the limbs motion. We obtained high correlation values of 0.87 ± 0.07 and 0.93 ± 0.02 for the elbow flexion and knee extension exercises, respectively, proving good stimulation application in real therapy-scenarios.