Functional electrical stimulation combined with voluntary cycling accentuates VO2 response in people with severe multiple sclerosis: A pilot study.

BACKGROUND: Lower limb muscle weakness and reduced balance due to disease progression in multiple sclerosis (MS) may make robust aerobic exercise difficult. Functional electrical stimulation (FES) cycling combined with voluntary cycling may allow people with severe MS to enhance the intensity of aerobic exercise. The aim of this study was to investigate the cardiorespiratory, power, and participant-reported perceptions during acute bouts of FES cycling, voluntary cycling, and FES cycling combined with voluntary cycling (FES assist cycling). METHODS: Participants with severe MS (Expanded Disability Status Scale [EDSS] ≥ 6.0) undertook three exercise trials on a leg cycle ergometer. Trial 1 involved 30 min of FES cycling; Trial 2 involved two 10-minute bouts of voluntary cycling separated by 10 min rest; and Trial 3 was a combination of trials 1 and 2 (FES assist cycling). Outcome measures included VO2 (volume of oxygen consumption), cycle power output, heart rate, RPE, and post-exercise perceptions of pain and fatigue. RESULTS: Ten people with severe MS participated (9 female; age 52.4 ± 9.98 y; EDSS 7.1 ± 0.6). The average VO2 during the 30-minute trials was significantly higher for FES assist cycling compared to voluntary cycling (429.7 ± 111.0 vs 388.5 ± 101.0 mL/min, 95% CI 23.4 to 113.0 mL/min, p = 0.01), with a large effect size (Hedges' g = 1.04). Participants reported similar rates of perceived exertion at the end of FES cycling (13 ± 2), voluntary cycling (14 ± 2), and FES assist cycling (15 ± 1); p = 0.14. Self-reported pain was higher during both FES cycling (5.4 vs 0.3; 95% CI 3.4 to 6.7, p = 0.01, Hedges' g = 2.07) and FES assist cycling (4.2 vs. 0.3; 95% CI 2.3 to 5.5, p = 0.01, Hedges' g = 1.71) than voluntary cycling, both with large effect sizes. There was no difference in self-reported fatigue at the end of each trial (p = 0.21). CONCLUSION: This study found FES assist cycling produced significantly higher VO2 values than voluntary cycling, although the clinical significance of these differences is unknown. Participants performed FES assist cycling at a self-reported RPE consistent with moderate to vigorous intensity, however it was considered light-intensity exercise when expressed by METS. FES assist cycling was no more fatiguing post-exercise than the other modes.

The effects of hybrid functional electrical stimulation interval training on aerobic fitness and fatigue in people with advanced multiple sclerosis: An exploratory pilot training study.

BACKGROUND: Improving aerobic fitness in people with advanced multiple sclerosis (MS) may reduce fatigue, and lower the risk of cardiovascular disease, as has been found for people with mild to moderate MS. Training targeting aerobic fitness can be challenging due to paresis, access to suitable equipment and fatigue. The aim of this study was to investigate whether people with advanced multiple sclerosis could perform functional electrical stimulation (FES) cycling combined with arm crank interval exercise (hybrid FES interval training) training, and its effects on aerobic fitness and fatigue. METHODS: Hybrid FES interval training was performed 2 d/wk for 12 weeks. Each session consisted of 40 min of continuous FES cycling with arm crank intervals of 30 s work/30 s rest added concurrently for 20 min. The intensity target was a minimum of 60 % of arm crank power and 'hard' measured by rate of perceived exertion (RPE). Attendance, compliance to intensity and time targets, adverse events, and drop outs were measured. Aerobic fitness was assessed by an arm crank maximal test. Fatigue was measured via the Modified Fatigue Impact Scale (MFIS). RESULTS: Seven participants (6 female; age 57.1 ± 7.8y; Expanded Disability Status Scale 7.1 ± 0.8) with advanced MS attended 80 ± 10.4 % of the scheduled exercise sessions and there were no adverse events or drop outs. Average RPE at the end of each training session was 15.1 ± 2.1, representing vigorous intensity exercise. Aerobic fitness did not change pre- to post-intervention (14.2 ± 5.7 to 14.8 ± 6.0 mL/kg/min [p = 0.43]), and resulted in a small effect size (ES) (0.30). The reduction in fatigue during the intervention (31.0 ± 10.4 to 21.7 ± 11.4 [p = 0.10]), resulted in a moderate to large ES (-0.77). CONCLUSION: Hybrid FES interval training could be performed 2 days per week for 12 weeks and represented vigorous intensity exercise, but there was no change in aerobic fitness. The reduction in participants' perceptions of fatigue represented a moderate to large ES, indicating hybrid FES interval training might be suitable for people with advanced MS who need exercise equipment appropriate for their condition. CLINICAL TRIAL REGISTRATION: This study was registered with Australian and New Zealand Clinical Trials Register (U1111-1194-2040).

Effects of Functional Electrical Stimulation Cycling Combined With Arm Cranking Exercise on Cardiorespiratory Fitness in People With Central Nervous System Disorders: A Systematic Review and Meta-analysis.

OBJECTIVE: To examine the evidence regarding the potential of hybrid functional electrical stimulation (FES) cycling for improving cardiorespiratory fitness for people with a mobility disability related to a central nervous system (CNS) disorder. DATA SOURCES: Nine electronic databases: MEDLINE, EMBASE, Web of Science, CINAHL, PsycInfo, SPORTDiscus, Pedro, Cochrane, and Scopus, were searched from inception until October 2022. STUDY SELECTION: Search terms included multiple sclerosis, spinal cord injury (SCI), stroke, Parkinson's disease, cerebral palsy, synonyms of FES cycling, arm crank ergometry (ACE) or hybrid exercise, and V̇o2. All experimental studies, including randomized controlled trials that included an outcome measure related to peak or sub-maximal V̇o2 were eligible. DATA EXTRACTION: From a total of 280 articles, 13 were studies included. The Downs and Black Checklist was used to assess study quality. Random effects (Hedges' g) meta-analyses were undertaken to determine whether there were differences in V̇o2peak during acute bouts of hybrid FES cycling vs other modes of exercise and changes resulting from longitudinal training. DATA SYNTHESIS: During acute bouts of exercise, hybrid FES cycling was moderately more effective than ACE (effect size [ES] of 0.59 (95% CI 0.15-1.02, P=.008) in increasing V̇o2peak from rest. There was a large effect on the increase of V̇o2peak from rest for hybrid FES cycling compared with FES cycling (ES of 2.36 [95% CI 0.83-3.40, P=.003]). Longitudinal training with hybrid FES cycling showed a significant improvement in V̇o2peak from pre to post intervention with a large, pooled ES of 0.83 (95% CI 0.24-1.41, P=.006). CONCLUSIONS: Hybrid FES cycling produced higher V̇o2peak compared with ACE or FES cycling during acute bouts of exercise. Hybrid FES cycling can improve cardiorespiratory fitness in people with SCI. Additionally, there is emerging evidence that hybrid FES cycling might increase aerobic fitness in people with mobility disability related to CNS disorders.

An exploratory study of exercise behaviours and barriers to participation in people with Charcot-Marie-Tooth disease: a focus on resistance training.

The aim of this study was to explore and describe the exercise behaviours and barriers in people with Charcot-Marie-Tooth disease (CMT), with a particular focus on resistance training (RT). Ninety-four Australian adults with a diagnosis of CMT completed an online survey. Fifty-seven percent of respondents reported performing some form of RT each week. Those performing RT engaged in more aerobic activity (P≤0.01) and were involved in longer periods of structured exercise (P<0.01) compared to those not performing RT. The RT group was more likely to perceive their exercise levels as acceptable (P<0.01), that following a program was important (P=0.02), and that exercise is beneficial (P=0.04). The RT group were more likely to have been advised to exercise (P=0.02). Common barriers to exercise were fatigue (64.9%), pain (57.4%), motivation (51.1%), and time (46.8%). RT status did not influence the type of barriers experienced. Weekly RT time was positively associated with exercise satisfaction (r=0.43, P<0.01) and walking distance prior to resting (r=0.29, P=0.04). The findings suggest that positive exercise experiences, advice, assistance from a trainer, and potentially greater resources may influence participation in RT for people with CMT.

Playing Disability Rugby League with Charcot-Marie-Tooth Disease: A Case Study.

Charcot-Marie-Tooth (CMT) disease is a common inherited neurological disorder that causes damage to peripheral nerves. Reports of CMT patients participating in team-based sports such as disability rugby league are scarce. The objective of this case report was to evaluate the benefits of participation in disability rugby league in a 50-year-old male with CMT. Leg muscle mass and strength was worse for the case subject compared to two age-matched CMT participants with an exercise history; however, evidence of greater function in the case subject was observed through better 6-min walk test performance. Performance in a series of sport specific tests was noticeably worse for the case subject compared to a fellow rugby league player (age matched) with cerebral palsy. Inferior in-game performance was observed for the case subject compared to his fellow rugby league player in terms of distance covered, top running speed, and intensity. However, the case subject may have assumed a different role when playing as evident by the different behaviours he displayed during the games (i.e., less player contacts, tackles, or touches, but more passes of the ball). This case study provides information concerning disability rugby league as an adjunctive mode of treatment for CMT populations.

Impact of maximal strength training on countermovement jump phase characteristics in athletes with cerebral palsy.

Analysis of the countermovement jump (CMJ) force-time curve phases provides insight into athlete neuromuscular function and methods by which jump height improves in response to training. A CMJ phase analysis and the dynamic strength index (DSI) have yet to be explored in athletes with cerebral palsy (CP). This study aimed to address this knowledge gap. Eleven state- to international-level athletes with CP completed a pre-post maximal strength training intervention with waitlist control. CMJ was assessed via force plate pre/post baseline and after the 12-week intervention. Following the intervention, CMJ height, takeoff velocity, and concentric phase peak and mean force, impulse and mean acceleration improved significantly (p = 0.006-0.001). No changes were observed in any eccentric braking phase variable (p = 0.79-0.13), while DSI lowered (p = 0.03). In athletes with CP, strength training increased CMJ concentric phase peak and mean force and impulse, increasing velocity and acceleration and therefore jump height. DSI lowered due to moderate and small increases in isometric mid-thigh pull and CMJ peak force, respectively. Unlike in non-disabled athletes, strength training did not alter any eccentric phase variable; therefore, other modalities may be required to further optimize jumping performance in athletes with CP.

Pilot Study of Enhancing Cardiorespiratory Exercise Response in People With Advanced Multiple Sclerosis With Hybrid Functional Electrical Stimulation.

OBJECTIVE: To investigate through a pilot study the acute cardiorespiratory responses during functional electrical stimulation (FES) cycling, arm crank ergometry (ACE), and a combination of ACE and FES cycling (hybrid FES cycling) in people with advanced multiple sclerosis (MS) to provide preliminary guidance for effective aerobic exercise prescription. DESIGN: Acute repeated measures. SETTING: Laboratory setting. PARTICIPANTS: Inclusion criteria was a diagnosis of MS, with Expanded Disability Status Scale (EDSS) 6.0-8.5. Included were 9 participants (N=9; 7 female, age 54.7±8.8y, EDSS 7.2±0.7). INTERVENTIONS: Participants were assessed on 3 different exercise modalities (FES cycling, ACE, hybrid FES cycling) at 40%, 60%, 80%, and 100% of mode-specific peak workload. MAIN OUTCOME MEASURES: Oxygen consumption and heart rate were measured at each workload. RESULTS: Hybrid FES cycling evoked a significantly higher oxygen consumption relative to body weight (V̇o2relative) (mL/kg/min) and heart rate (beats per minute [BPM]) at most workloads compared with ACE or FES cycling. At the 100% workload, heart rate for hybrid FES cycling was 125 BPM (range, 113-148 BPM) and was significantly higher than ACE at 99 BPM (range, 95-119 BPM) (P=.008) and FES cycling at 94 BPM (range, 79-100 BPM) (P=.008). Similarly, at the 100% workload, V̇o2relative for hybrid FES cycling was 11.8 mL/kg/min (range, 7.6-17.6 mL/kg/min) and was significantly higher than ACE at 8.9 mL/kg/min (range, 5.3-12.5 mL/kg/min) (P=.012) and FES cycling at 6.8 mL/kg/min (range, 4.1-9.2 mL/kg/min) (P=.012). CONCLUSIONS: This pilot study showed that hybrid FES cycling can elicit a greater cardiorespiratory response than ACE or FES cycling in people with advanced MS. Thus, hybrid FES cycling might provide a potent enough stimulus to induce clinically relevant changes in cardiorespiratory fitness. Training studies are warranted to document the magnitude and sustainability of aerobic capacity adaptations to hybrid FES cycling and associated health outcomes in advanced MS.

Strength Training to Improve Performance in Athletes With Cerebral Palsy: A Systematic Review of Current Evidence.

Fleeton, JRM, Sanders, RH, and Fornusek, C. Strength training to improve performance in athletes with cerebral palsy: A systematic review of current evidence. J Strength Cond Res 34(6): 1774-1789, 2020-Persons with cerebral palsy (CP) can partake in many different forms of organized sport including elite competition at state and international levels. There is limited evidence on how CP athletes should train to enhance performance. The purposes of this article were to conduct a systematic review of the current evidence on ambulatory individuals with CP for (a) strength and functional improvement through strength training; (b) potential sports performance improvement through strength training; (c) the identification of risk and special considerations associated with strength and conditioning for this population, and; (d) the identification of future research foci to educate strength and conditioning coaches on specific program design for elite CP athletes. Seven electronic databases were searched for studies investigating resistance training interventions. The databases were also searched for training interventions or investigations into sports performance in athletes with CP competing at regional level or above. Thirty articles were included in the systematic review of strength training, and 23 articles included in the narrative review of training for sports performance. High-quality evidence indicates that resistance training can improve muscular strength in individuals with CP, with some preliminary evidence of structural and neurological adaptations. However, there is limited evidence for functional improvements. Limited research has examined the performance capacity of athletes with CP, and no training interventions have been conducted. Coaches should employ existing guidelines when designing programs while considering specific athlete limitations. Initially, the focus should be increasing athlete muscular strength before considering specific sport demands.

Lessons from Vienna: stakeholder perceptions of functional electrical stimulation technology and a conceptual model for practice.

Aim: Functional electrical stimulation (FES) is a technology that can be used on paralyzed muscles to allow them to move. It has been used in populations with muscle paralysis or weakness for exercise, such as spinal cord injury (SCI) and multiple sclerosis. In order to improve technology, it is vital to understand from a qualitative perspective, issues surrounding device development and implementation.Materials and Methods: In 2016, a study was conducted at the Medical University of Vienna that sought to unravel perspectives of FES exercise from the perspective of clinicians, engineers and researchers. Semi-structured, qualitative interviews were conducted on a sample of participants from the conference (n = 22). Interviews were transcribed verbatim, and text data were analysed.Results: Following this analysis, a conceptual model of FES application in the home environment was derived. We show that the likelihood of continuing FES over time may be influenced by expectations and initial education, as perceived by stakeholders.Conclusion: This model provides a tool by which researchers or clinicians may implement FES in the home environment and may assist in the increased uptake of FES exercise at home for people who may reap benefits from its use.Implications for RehabilitationFunctional electrical stimulation (FES) is a technology that enables individuals with paralysis, such as Spinal Cord Injury or Multiple Sclerosis, to exercise.Motivation and support networks, along with adequate initial education, are essential should patients be able to successfully use FES for exercise.There are unique issues associated with performing FES in the home, and compliance may be influenced by how patients perceive FES with regard to providing benefits, and what their initial expectations are.Communication and education are essential for all parties involved in the provision of FES treatment, to ensure successful treatment with FES at home.

Acute Effect of Kettlebell Swings on Sprint Performance.

Previous research has shown that kettlebell swings (KBS), utilizing the hip-hinge technique, exhibit similar lower-limb muscle activation patterns to sprint running. This study investigated whether the inclusion of KBS in the warm-up enhances sprint performance. Moderately trained males (n = 12) and females (n = 8) performed KBS and a control (CON) condition (passive rest) in random order before performing three 20-m sprint trials separated by 4 minutes. No condition (KBS versus CON) effects, time effects or condition by time interactions were found for sprint times at 5-m and 10-m. A significant time effect was found for sprint time at 20-m with faster sprint time at 12 minutes compared to 4 minutes (p = 0.022). No condition effect or condition by time interaction was found for sprint time at 20-m. Small to moderate correlations were found for change in sprint time (CON minus KBS) and KBS load at 4, 8, and 12 minutes. It appears the KBS is not effective for potentiating 20-m sprint performance; however, any potential benefit from the inclusion of KBS as a preconditioning exercise for sprinting may be influenced by individual strength capabilities with KBS.

The effect of auditory stimulus training on swimming start reaction time.

Task-specific auditory training can improve sensorimotor processing times of the auditory reaction time (RT). The majority of competitive swimmers do not conduct habitual start training with the electronic horn used to commence a race. We examined the effect of four week dive training interventions on RT and block time (BT) of 10 male adolescent swimmers (age 14.0 ± 1.4 years): dive training with auditory components (speaker and electronic horn) (n = 5) and dive training without auditory components (n = 5). Auditory stimulus dive training significantly reduced swimming start RT, compared with dive training without auditory components (p < 0.01), with a group mean RT reduction of 13 ± 9 ms. Four of the five swimmers that received auditory stimulus training showed medium to large effect size reductions in RT (d = 0.74; 1.32; 1.40; 1.81). No significant changes to swimmers' BTs were evident in either dive training intervention. The adolescent swimmers' results were compared against six male elite swimmers (age 19.8 ± 1.0 years). The elite swimmers had significantly shorter BTs (p < 0.05) but no significant difference in RTs. Auditory stimulus dive training should be explored further as a mechanism for improving swimming start performance in elite swimmers who have pre-established optimal BTs.

Body composition and its association with physical performance, quality of life, and clinical indictors in Charcot-Marie-Tooth disease: a pilot study.

AIM: To investigate whether the amount and distribution of lean body mass and fat mass is associated with disease severity in adults with Charcot-Marie Tooth. METHODS: Ten participants (age 46 ± 13 y, height 1.7 ± 0.1 m, and body mass 77 ± 17 kg) with Charcot-Marie Tooth disease were involved in this study. Participants were evaluated for quality of life, falls efficacy, balance, mobility, muscle strength, and power. Body composition was measured using dual energy x-ray absorptiometry. Statistical analyses were conducted on subsets of all participants. RESULTS: Better static balance was associated with higher lean body mass of the lower leg (r = 0.73, p = 0.03), while superior leg press strength and power was associated with greater lean body mass of the leg and lower leg (r ≥ 0.80, p ≤ 0.01). Faster habitual walking speed and enhanced quality of life was associated with lower fat mass of several regions. CONCLUSION: Our study seems to suggest that assessing of body composition could assist with monitoring of disease progression in people with Charcot-Marie Tooth; however these findings need to be substantiated in a larger cohort. Implications for Rehabilitation Higher lean body mass and lower fat mass of the legs is associated with better physical performances in people with Charcot-Marie-Tooth disease. Lower fat mass is related to greater quality of life and reduced clinical symptoms in people with Charcot-Marie-Tooth disease. Optimising favorable body composition profiles (higher lean body mass and lower fat mass) in people with Charcot-Marie-Tooth disease may be highly clinically relevant.

Reporting for Duty: The duty cycle in Functional Electrical Stimulation research. Part I: Critical commentaries of the literature.

There are several parameters that can be modulated during electrical stimulation-induced muscle contraction to obtain external work, i.e., Functional Electrical Stimulation (FES). The literature has several reports of the relationships of parameters such as frequency, pulse width, amplitude and physiological or biomechanical outcomes (i.e., torque) when these parameters are changed. While these relationships are well-described, lesser known across the literature is how changing the duty cycle (time ON and time OFF) of stimulation affects the outcomes. This review provides an analysis of the literature pertaining to the duty cycle in electrical stimulation experiments. There are two distinct sections of this review - an introduction to the duty cycle and definitions from literature (part I); and contentions from the literature and proposed frameworks upon which duty cycle can be interpreted (part II). It is envisaged that the two reviews will highlight the importance of modulating the duty cycle in terms of muscle fatigue in mimicking physiological activities. The frameworks provided will ideally assist in unifying how researchers consider the duty cycle in electrical stimulation (ES) of muscles.

The duty cycle in Functional Electrical Stimulation research. Part II: Duty cycle multiplicity and domain reporting.

In part I of this review, we introduced the duty cycle as a fundamental parameter in controlling the effect of electrical stimulation pulse trains on muscle structural and functional properties with special emphasis on fatigue. Following on from a survey of the literature, we discuss here the relative ability of intermittent and continuous stimulation to fatigue muscle. In addition, pertinent literature is explored on a more deeper level, highlighting contentions regarding the duty cycle across studies. In response to literature inconsistencies, we propose frameworks upon which the duty cycle parameter may be specified. We present the idea of domain reporting for the duty cycle, and illustrate with practical examples. In addition we dig further into the literature and present a set of notations that have been used by different researchers to report the duty cycle. We also propose the idea of the duty cycle multiple, which together with domain reporting, will help researchers understand more precisely duty cycles of electrical stimulation. As a case study, we also show how the duty cycle has been looked at by researchers in the context of pressure sore attenuation in patients. Together with part I, it is hoped that the frameworks suggested provide a complete picture of how duty cycle has been discussed across the literature, and gives researchers a more trans-theoretical basis upon which they may report the duty cycle in their studies. This may also lead to a more precise specification of electrical stimulation protocols used in patients.

The Vienna FES Interview Protocol - A mixed-methods protocol to elucidate the opinions of various individuals responsible for the provision of FES exercise.

Functional Electrical Stimulation (FES) is the production of electrically elicited muscle contractions to perform a function or task. It has been used as a method to regain lost body functions or support weak body functions, and as such, has been clinically available since the early seventies. Some methods are applied routinely while others have not been translated to the bedside, or are still largely restricted to laboratory use. Progress in this field might be achieved by a strong cooperation of patients, clinicians, therapists and engineers. A better insight into multiple perspectives may help in understanding the shortcomings of current FES technology. This will help direct future research efforts into design of systems and potential application in relevant populations. In addition, these findings can assist with the translation of FES technology into a community context. We outline an interview protocol designed for use at the 12th Vienna International Workshop on Functional Electrical Stimulation where the mentioned experts from the field of FES met.

Comparison of strategies and performance of functional electrical stimulation cycling in spinal cord injury pilots for competition in the first ever CYBATHLON.

Functional Electrical Stimulation (FES) can elicit muscular contraction and restore motor function in paralyzed limbs. FES is a rehabilitation technique applied to various sensorimotor deficiencies and in different functional situations, e.g. grasping, walking, standing, transfer, cycling and rowing. FES can be combined with mechanical devices. FES-assisted cycling is mainly used in clinical environments for training sessions on cycle ergometers, but it has also been adapted for mobile devices, usually tricycles. In October 2016, twelve teams participated in the CYBATHLON competition in the FES-cycling discipline for persons with motor-complete spinal cord injury. It was the first event of this kind and a wide variety of strategies, techniques and designs were employed by the different teams in the competition. The approaches of the teams are detailed in this special issue. We hope that the knowledge contained herein, together with recent positive results of FES for denervated degenerating muscles, will provide a solid basis to encourage improvements in FES equipment and open new opportunities for many patients in need of safe and effective FES management. We hope to see further developments and/or the benefit of new training strategies at future FES competitions, e.g. at the Cybathlon 2020 (www.cybathlon.ethz.ch).

Relationship between physical performance and quality of life in Charcot-Marie-Tooth disease: a pilot study.

Charcot-Marie-Tooth (CMT) is a rare inherited peripheral neuropathy in which quality of life (QoL) is reduced compared with the general population. This paper investigates the relationship between QoL and physical performance in people with CMT with the aim of identifying avenues for future research into rehabilitation strategies. Cross-sectional data was obtained from 10 participants (5 men, 5 women, age 46 ± 13 years, height 1.7 ± 0.1 m, body mass 77 ± 17 kg) with CMT (CMT1A n = 5; CMT-X n = 3; unknown genetic origin n = 2). Participants were evaluated for QoL, falls efficacy (FES), balance, mobility, muscle strength, and power. Physical component score (PCS) of the Short Form-36 (SF-36) was significantly and directly related to higher leg press power (r = 0.75, p = 0.02). Better FES scores were significantly related to faster habitual gait speed (r = -0.70, p = 0.02), left hip abduction, and seated row strength (r = -0.68, p = 0.03; r = -0.73, p = 0.03, respectively). Future research should aim to substantiate these preliminary findings in a larger cohort and investigate whether interventions targeting muscle strength and power can improve QoL and mobility outcomes in people with CMT.

A novel motion sensor-driven control system for FES-assisted walking after spinal cord injury: A pilot study.

This pilot study reports the development of a novel closed-loop (CL) FES-gait control system, which employed a finite-state controller that processed kinematic feedback from four miniaturized motion sensors. This strategy automated the control of knee extension via quadriceps and gluteus stimulation during the stance phase of gait on the supporting leg, and managed the stimulation delivered to the common peroneal nerve (CPN) during swing-phase on the contra-lateral limb. The control system was assessed against a traditional open-loop (OL) system on two sensorimotor 'complete' paraplegic subjects. A biomechanical analysis revealed that the closed-loop control of leg swing was efficient, but without major advantages compared to OL. CL automated the control of knee extension during the stance phase of gait and for this reason was the method of preference by the subjects. For the first time, a feedback control system with a simplified configuration of four miniaturized sensors allowed the addition of instruments to collect the data of multiple physiological and biomechanical variables during FES-evoked gait. In this pilot study of two sensorimotor complete paraplegic individuals, CL ameliorated certain drawbacks of current OL systems - it required less user intervention and accounted for the inter-subject differences in their stimulation requirements.

Examining hand dominance using dynamometric grip strength testing as evidence for overwork weakness in Charcot-Marie-Tooth disease: a systematic review and meta-analysis.

This systematic review with a meta-analysis of studies was carried out to evaluate the potential of overwork weakness on the basis of grip strength of dominant and nondominant hands in individuals with Charcot-Marie-Tooth disease (CMT). Numerous electronic databases were searched from the earliest records to February 2016. Studies of any design including participants older than 18 years of age with a confirmed diagnosis of CMT that measured grip strength of both hands using dynamometric testing were eligible for inclusion. Of 12 593 articles identified following removal of duplicates, five articles fulfilled the criteria. A total of 166 participants, mostly with CMT1 or CMT2, were described from the studies included. Hand and finger pinch grip strength for the dominant compared with the nondominant hand was not statistically different. There is no definitive evidence that preferential use of the dominant hand in CMT impairs function relative to the nondominant hand. Thus, robust exercise trials of progressive resistance training are needed to understand the extent of adaptations possible and provide evidence of the safety of such regimens.

The effect of nitrate supplementation on muscle contraction in healthy adults.

This study examined the effect of dietary supplementation with inorganic nitrate ([Formula: see text] ) on markers of contractile function in human knee extensors. In a double-blinded, randomized cross-over design, 18 (12 M) healthy participants undertook four days of supplementation with either nitrate-rich beetroot juice (NITRATE; days 1-3: 525 mg [Formula: see text], day 4: 1050 mg [Formula: see text]) or nitrate-depleted beetroot juice (PLACEBO). On the fourth day, isometric knee extension force was assessed during a series of voluntary and electrically evoked (stimulation) tests. In addition, muscular fatigue was examined in two separate continuous-stimulation (0.8 s tetanus with a 1:1 work:rest ratio for 102.4 s) fatigue tests, one with and one without blood flow restriction. There were no differences for maximum voluntary contraction, peak twitch force, half-relaxation time and the force-frequency relationship for stimulations up to 100 Hz between the NITRATE and PLACEBO trials. No differences between trials were observed in the non-restricted fatigue test, however NITRATE was found to attenuate the decline in force during the restricted test, such that the force at the 80 s mark (PLACEBO: 66 ± 11 vs. NITRATE 74 ± 9% of initial force; P = .01) and 102 s mark (PLACEBO: 47 ± 8% vs. NITRATE 55 ± 8%; P < .01) were significantly higher. These results suggest that four days of [Formula: see text] supplementation elicits peripheral responses in muscle that attenuate muscular fatigue during exhaustive exercise under hypovolemic conditions. This ergogenic action is likely attributable to improved Ca(2+) handling in the muscle, or enhanced perfusion during ischemia.