Cardiorespiratory responses during functional electrical stimulation cycling and electrical stimulation isometric exercise

Should We Use the Functional Electrical Stimulation-Cycling Exercise in Clinical Practice? Physiological and Clinical Effects Systematic Review With Meta-analysis

OBJECTIVE

To examine the evidence regarding functional electrical stimulation cycling's (FES-cycling's) physiological and clinical effects.

DATA SOURCES

The study was conducted in accordance with the preferred reporting items for systematic reviews and meta-analyses protocol. PubMed, Embase, Cochrane Review, CINAHL, Scopus, Sport Discus, and Web of Science databases were used.

STUDY SELECTION

Randomized controlled trials involving FES-cycling were included. Studies that did not involve FES-cycling in the intervention group or without the control group were excluded. Two reviewers screened titles and abstracts and then conducted a blinded full-text evaluation. A third reviewer resolved the discrepancies.

DATA EXTRACTION

Meta-analysis was performed using inverse variance for continuous data, with effects measured using the mean difference and random effects analysis models. A 95% confidence interval was adopted. The significance level was set at P<.05, and trends were declared at P=.05 to ≤.10. The I2 method was used for heterogeneity analysis. The minimal clinically important difference was calculated. Methodological quality was assessed using the risk of bias tool for randomized trials. The Grading of Recommendations Assessment, Development, and Evaluation method was used for the quality of the evidence analysis.

DATA SYNTHESIS

A total of 52 studies were included. Metabolic, cardiocirculatory, ventilatory, and peripheral muscle oxygen extraction variables presented statistical (P<.05) and clinically important differences favoring FES-cycling, with moderate-to-high certainty of evidence. It also presented statistical (P<.05) and clinically important improvements in cardiorespiratory fitness, leg and total body lean mass, power, physical fitness in intensive care (moderate-to-high certainty of evidence), and torque (low certainty of evidence). It presented a trend (P=.05 to ≤.10) of improvement in muscle volume, spasticity, and mobility (low-to-moderate certainty of evidence). It showed no difference (P>.10) in 6-minute walking distance, muscle cross-sectional area, bone density, and length of intensive care unit stay (low-to-moderate certainty of evidence).

CONCLUSIONS

FES-cycling exercise is a more intense stimulus modality than other comparative therapeutic modalities and presented clinically important improvement in several clinical outcomes.

Electrical Stimulation for Preventing Skin Injuries in Denervated Gluteal Muscles-Promising Perspectives from a Case Series and Narrative Review

Spinal cord injury (SCI) where the lower motor neuron is compromised leads to atrophy and degenerative changes in the respective muscle. This type of lesion becomes especially critical when the gluteal muscles and/or the hamstrings are affected as they usually offer a cushioning effect to protect from skin injuries. Previous research conducted over the past 30 years has made advancements in the development of parameters for the optimal application of long pulse stimulation with the aim to restore muscle structure and trophic aspects in people with chronic SCI (<20 years post-injury). This work provides an overview of previous achievements in the field through a narrative literature review before presenting preliminary results in the form of a case series from an ongoing study investigating the acute effects of six months of long pulse stimulation on the tissue composition of the gluteal muscles in five people with chronic SCI (>20 years post-injury). Participants underwent a 33-min home-based long pulse stimulation program five times a week, and their muscle and adipose tissue thicknesses were assessed at baseline, after three and six months, respectively, using magnetic resonance imaging. The results show that the largest increase in muscle thickness occurred at the level of the height of the acetabulum (+44.37%; χ2(2) = 0.5; p = 0.779), whereas the most important decrease in adipose tissue occurred at the level of the sacroiliac joint (SIJ) reference (−11.43%; χ2(2) = 1.6; p = 0.449) within only six months of regular stimulation despite the preceding long denervation period. The underlying mechanism and physiology of muscular resuscitation from myofibrillar debris as presented in chronic denervation to functional contractile entities remain to be investigated further.

Changes in spasticity following functional electrical stimulation cycling in patients with spinal cord injury: A systematic review

CONTEXT

Spasticity is one of the most common secondary impairment after spinal cord injury (SCI). It can lead to an increase in the level of disability. The functional electrical stimulation cycling (FES-cycling) promotes recovery in patients with SCI. No systematic review has been published examining the influence of FES-cycling on the spasticity of lower extremities post-SCI.Objective: This review aimed to investigate the effects of the FES-cycling on the lower extremities spasticity in patients with SCI.Methods: PubMed, Scopus, PEDro, REHABDATA, Web of Science, and MEDLINE were searched until December 2019. The methodological quality was assessed using the Physiotherapy Evidence Database (PEDro) scale.Results: Ten studies were met the inclusion criteria. Two were randomized clinical trials, cohort study (n = 2), and pilot study (n=6). The scores on the PEDro scale ranged from one to nine, with a median score of three. The results showed evidence for the beneficial effects of FES-cycling on the spasticity of lower extremities in individuals with SCI.Conclusion: The FES-cycling intervention may reduce the lower extremities spasticity in patients with various injury levels of SCI. It is not a suitable intervention for medically unstable patients or with contraindication for lower extremities movement. Further randomized controlled trials with a large sample size strongly warranted to confirm our findings.

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 cranking exercise (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 to 8.5. Included were 9 participants (7 female, age 54.7 ± 8.8 years, EDSS 7.0 ± 7.2).

INTERVENTION

Participants were assessed on three 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 (VO₂) and heart rate (HR) were measured at each workload.

RESULTS

Hybrid FES cycling evoked a significantly higher VO_2relative (mL∙kg^-1∙min^-1) and HR (bpm) at most workloads as compared with ACE or FES cycling. At the 100% workload, HR for Hybrid FES cycling was 125 (113-148) bpm and was significantly higher than ACE at 99 (95-119) bpm (p=0.008) and FES cycling at 94 (79-100) bpm (p=0.008). Similarly, at the 100% workload, VO_2relative for Hybrid FES cycling was 11.8 (7.6-17.6) mL∙kg^-1∙min^-1 and was significantly higher than ACE at 8.9 (5.3-12.5) mL∙kg^-1∙min^-1 (p=0.012) and FES cycling at 6.8 (4.1-9.2) mL∙kg^-1∙min^-1 (p=0.012).

CONCLUSIONS

This pilot study showed that Hybrid FES cycling can elicit a greater cardiorespiratory response compared to 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.

Exercise Interventions Targeting Obesity in Persons With Spinal Cord Injury

Spinal cord injury (SCI) results in an array of cardiometabolic complications, with obesity being the most common component risk of cardiometabolic disease (CMD) in this population. Recent Consortium for Spinal Cord Medicine Clinical Practice Guidelines for CMD in SCI recommend physical exercise as a primary treatment strategy for the management of CMD in SCI. However, the high prevalence of obesity in SCI and the pleiotropic nature of this body habitus warrant strategies for tailoring exercise to specifically target obesity. In general, exercise for obesity management should aim primarily to induce a negative energy balance and secondarily to increase the use of fat as a fuel source. In persons with SCI, reductions in the muscle mass that can be recruited during activity limit the capacity for exercise to induce a calorie deficit. Furthermore, the available musculature exhibits a decreased oxidative capacity, limiting the utilization of fat during exercise. These constraints must be considered when designing exercise interventions for obesity management in SCI. Certain forms of exercise have a greater therapeutic potential in this population partly due to impacts on metabolism during recovery from exercise and at rest. In this article, we propose that exercise for obesity in SCI should target large muscle groups and aim to induce hypertrophy to increase total energy expenditure response to training. Furthermore, although carbohydrate reliance will be high during activity, certain forms of exercise might induce meaningful postexercise shifts in the use of fat as a fuel. General activity in this population is important for many components of health, but low energy cost of daily activities and limitations in upper body volitional exercise mean that exercise interventions targeting utilization and hypertrophy of large muscle groups will likely be required for obesity management.

Ergogenic Effect of Neuromuscular Electrical Stimulation During Rest and Submaximal Exercise

The primary aim of this investigation was to determine the ergogenic effect of neuromuscular electrical stimulation (NMES) amongst twenty apparently healthy males during submaximal exercise. In Session 1, 20 participants (Age = 35.0 ± 15.0 yrs; Height = 179.9 ± 8.5 cm; Body Mass = 85.4 ± 12.0 kg) were familiarized with all equipment. Sessions 2-4 included the following randomized 5-min trials a) Rest and Rest+NMES, b) Rest, Arms-Only, Arms+NMES, and c) Rest, Arms+Legs, Arms+Legs+NMES. Physiological variables collected during rest and submaximal exercise were volume of oxygen (VO₂), heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), respiratory exchange ratio (RER), and rate pressure product (RPP). Paired sample t-test was used to determine significant mean differences between the NMES and non-NMES trials. Bonferroni post-hoc analysis established alpha at 0.008. From the 18 paired t-tests, the only observed significant mean difference (t(19) = -6.4, p < 0.001) was RER values between the Arms-Only trial compared to the Arms+NMES trial (0.94 and 1.00, respectively). While RER displayed a significant difference, from a practical perspective, however, these differences were deemed non-physiologically significant. Viewed in concert, findings from this study suggests that NMES utilization does not evoke an acute ergogenic effect amongst an apparently healthy male population.

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.

Strategies for Rapid Muscle Fatigue Reduction during FES Exercise in Individuals with Spinal Cord Injury: A Systematic Review

Background

Rapid muscle fatigue during functional electrical stimulation (FES)-evoked muscle contractions in individuals with spinal cord injury (SCI) is a significant limitation to attaining health benefits of FES-exercise. Delaying the onset of muscle fatigue is often cited as an important goal linked to FES clinical efficacy. Although the basic concept of fatigue-resistance has a long history, recent advances in biomedical engineering, physiotherapy and clinical exercise science have achieved improved clinical benefits, especially for reducing muscle fatigue during FES-exercise. This review evaluated the methodological quality of strategies underlying muscle fatigue-resistance that have been used to optimize FES therapeutic approaches. The review also sought to synthesize the effectiveness of these strategies for persons with SCI in order to establish their functional impacts and clinical relevance.

Methods

Published scientific literature pertaining to the reduction of FES-induced muscle fatigue was identified through searches of the following databases: Science Direct, Medline, IEEE Xplore, SpringerLink, PubMed and Nature, from the earliest returned record until June 2015. Titles and abstracts were screened to obtain 35 studies that met the inclusion criteria for this systematic review.

Results

Following the evaluation of methodological quality (mean (SD), 50 (6) %) of the reviewed studies using the Downs and Black scale, the largest treatment effects reported to reduce muscle fatigue mainly investigated isometric contractions of limited functional and clinical relevance (n = 28). Some investigations (n = 13) lacked randomisation, while others were characterised by small sample sizes with low statistical power. Nevertheless, the clinical significance of emerging trends to improve fatigue-resistance during FES included (i) optimizing electrode positioning, (ii) fine-tuning of stimulation patterns and other FES parameters, (iii) adjustments to the mode and frequency of exercise training, and (iv) biofeedback-assisted FES-exercise to promote selective recruitment of fatigue-resistant motor units.

Conclusion

Although the need for further in-depth clinical trials (especially RCTs) was clearly warranted to establish external validity of outcomes, current evidence was sufficient to support the validity of certain techniques for rapid fatigue-reduction in order to promote FES therapy as an integral part of SCI rehabilitation. It is anticipated that this information will be valuable to clinicians and other allied health professionals administering FES as a treatment option in rehabilitation and aid the development of effective rehabilitation interventions.

The effect of functional electrical stimulation cycling on late functional improvement in patients with chronic incomplete spinal cord injury

STUDY DESIGN

Prospective single-arm study.

OBJECTIVES

To investigate the effect of functional electrical stimulation (FES) cycling on late functional recovery, spasticity, gait parameters and oxygen consumption during walking in patients with chronic incomplete spinal cord injury (SCI).

SETTING

Turkish Armed Forces Rehabilitation Center, Ankara, Turkey.

METHODS

Ten patients with chronic (duration of more than 2 years) incomplete SCI who could ambulate at least 10 m independently or with the assistance of a cane or walker, but no hip-knee-ankle-foot orthosis. The subjects underwent 1-h FES cycling sessions three times a week for 16 weeks. Outcome measures including the total motor score, the Functional Independence Measure (FIM) score, the Modified Ashworth Scale for knee spasticity, temporal spatial gait parameters and oxygen consumption rate during walking were assessed at baseline, 3 and 6 months after the baseline.

RESULTS

There were statistically significant improvements in total motor scores, the FIM scores and spasticity level at the 6-month follow-up (P<0.01). The changes in gait parameters reached no significant level (P>0.05). Oxygen consumption rate of the patients showed significant reduction at only 6 months compared with baseline (P<0.01).

CONCLUSION

The results suggest that FES cycling may provide some functional improvements in the late period of SCI.

SPONSORSHIP

The study was supported by The Scientific and Technological Research Council of Turkey (TUBITAK).