Skeletal muscle hypertrophy and decreased intramuscular fat after unilateral resistance training in spinal cord injury: case report

Multiparametric MRI Assessment of Morpho-Functional Muscle Changes Following a 6-Month FES-Cycling Training Program: Pilot Study in People With a Complete Spinal Cord Injury

Background

Spinal cord injuries (SCIs) cause debilitating secondary conditions such as severe muscle deterioration, cardiovascular, and metabolic dysfunctions, significantly impacting patients' quality of life. Functional electrical stimulation (FES) combined with cycling exercise (FES-cycling) has shown promise in improving muscle function and health in individuals with SCI.

Objective

This pilot study aimed to investigate the potential role of multiparametric magnetic resonance imaging (MRI) to assess muscle health during and after an FES-cycling rehabilitation program.

Methods

Four male participants with chronic SCI underwent a 6-month FES-cycling training program, consisting of two 30-minute sessions per week. MRI scans were performed at baseline (T0), after 3 months (T1), at the end of the training (T2), and 1-month posttraining (T3). The MRI protocol included T1-weighted imaging for volume quantification, Dixon imaging for fat fraction, multi-echo spin echo for T2 relaxation times, and diffusion tensor imaging to assess diffusion parameters.

Results

Muscle hypertrophy was observed, with an average increase in muscle volume of 22.3% at T1 and 36.7% at T2 compared with baseline. One month posttraining, muscle volume remained 23.2% higher than baseline. Fat fraction decreased from 11.1% at T0 to 9.1% at T2, with a rebound to 10.9% at T3. T2 relaxation times showed a reduction even though this was not consistent among participants. Diffusion tensor imaging parameters revealed subtle changes in muscle tissue microstructure, with a decrease in fractional anisotropy mainly associated to an increase of radial diffusivity.

Conclusions

Although preliminary, this study provides evidence that 6 months of low-intensity FES-bike training can increase muscle volume and decrease fat infiltration in individuals with SCI. The study demonstrates that the use of a multiparametric MRI provides comprehensive insights into both macroscopic and microscopic changes within muscle tissues, supporting its integration into clinical practice for assessing the efficacy of rehabilitation interventions.

The Effect of Lower Limb Combined Neuromuscular Electrical Stimulation on Skeletal Muscle Cross-Sectional Area and Inflammatory Signaling

In individuals with a spinal cord injury (SCI), rapid skeletal muscle atrophy and metabolic dysfunction pose profound rehabilitation challenges, often resulting in substantial loss of muscle mass and function. This study evaluates the effect of combined neuromuscular electrical stimulation (Comb-NMES) on skeletal muscle cross-sectional area (CSA) and inflammatory signaling within the acute phase of SCI. We applied a novel Comb-NMES regimen, integrating both high-frequency resistance and low-frequency aerobic protocols on the vastus lateralis muscle, to participants early post-SCI. Muscle biopsies were analyzed for CSA and inflammatory markers pre- and post-intervention. The results suggest a potential preservation of muscle CSA in the Comb-NMES group compared to a control group. Inflammatory signaling proteins such as TLR4 and Atrogin-1 were downregulated, whereas markers associated with muscle repair and growth were modulated beneficially in the Comb-NMES group. The study's findings suggest that early application of Comb-NMES post-SCI may attenuate inflammatory pathways linked to muscle atrophy and promote muscle repair. However, the small sample size and variability in injury characteristics emphasize the need for further research to corroborate these results across a more diverse and extensive SCI population.

The effect of home-based neuromuscular electrical stimulation-resistance training and protein supplementation on lean mass in persons with spinal cord injury: A pilot study

In persons with a spinal cord injury (SCI), resistance training using neuromuscular electrical stimulation (NMES-RT) increases lean mass in the lower limbs. However, whether protein supplementation in conjunction with NMES-RT further enhances this training effect is unknown. In this randomized controlled pilot trial, 15 individuals with chronic SCI engaged in 3 times/week NMES-RT, with (NMES+PRO, n = 8) or without protein supplementation (NMES, n = 7), for 12 weeks. Before and after the intervention, whole body and regional body composition (DXA) and fasting glucose and insulin concentrations were assessed in plasma. Adherence to the intervention components was ≥96%. Thigh lean mass was increased to a greater extent after NMES+PRO compared to NMES (0.3 (0.2, 0.4) kg; p < 0.001). Furthermore, fasting insulin concentration and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) were decreased similarly in both groups (fasting insulin: 1 [-9, 11] pmol∙L-1; HOMA-IR: 0.1 [-0.3, 0.5] AU; both p ≥ 0.617). Twelve weeks of home-based NMES-RT increased thigh lean mass, an effect that was potentiated by protein supplementation. In combination with the excellent adherence and apparent improvement in cardiometabolic health outcomes, these findings support further investigation through a full-scale randomized controlled trial.

The Effect of Lower Limb Combined Neuromuscular Electrical Stimulation on Skeletal Muscle Signaling for Glucose Utilization, Myofiber Distribution, and Metabolic Function after Spinal Cord Injury

Maintaining healthy myofiber type and metabolic function early after spinal cord injury (SCI) may prevent chronic metabolic disorders. This study compares the effects of a 2-5 week combined (aerobic + resistance) neuromuscular electrical stimulation (Comb-NMES) regimen versus a sham control treatment on muscle protein signaling for glucose uptake, myofiber type distribution, and metabolic function. Twenty participants (31 ± 9 years of age) with an SCI (C4-L1, AIS level A-C) within 14 days of the SCI were randomly assigned to control (N = 8) or Comb-NMES (N = 12). Sessions were given three times per week. Fasting blood samples and vastus lateralis muscle biopsies were collected 24-48 h before or after the last session. Western blots were performed to quantify proteins, immunohistochemical analyses determined muscle myofiber distribution, and enzymatic assays were performed to measure serum glucose, insulin, and lipids. Our main findings include a decrease in fasting glucose (p < 0.05) and LDL-C (p < 0.05) levels, an upregulation of CamKII and Hexokinase (p < 0.05), and an increase in type I (+9%) and a decrease in type IIx (-36%) myofiber distribution in response to Comb-NMES. Our findings suggest that maintaining healthy myofiber type and metabolic function may be achieved via early utilization of Comb-NMES.

Effect of 8-week frequency-specific electrical muscle stimulation combined with resistance exercise training on muscle mass, strength, and body composition in men and women: a feasibility and safety study

In recent years, electrical muscle stimulation (EMS) devices have been developed as a complementary training technique that is novel, attractive, and time-saving for physical fitness and rehabilitation. While it is known that EMS training can improve muscle mass and strength, most studies have focused on the elderly or specific patient populations. The aim of this study was to investigate the effects of frequency-specific EMS combined with resistance exercise training for 8 weeks on muscle mass, strength, power, body composition, and parameters related to exercise fatigue. Additionally, we aimed to evaluate the feasibility and safety of EMS as an exercise aid to improve body composition. We recruited 14 male and 14 female subjects who were randomly assigned to two groups with gender parity (seven male and seven female/group): (1) no EMS group (age: 21.6 ± 1.7; height: 168.8 ± 11.8 cm; weight: 64.2 ± 14.4 kg) and (2) daily EMS group (age: 21.8 ± 2.0; height: 167.8 ± 9.9 cm; weight: 68.5 ± 15.5 kg). The two groups of subjects were very similar with no significant difference. Blood biochemical routine analysis was performed every 4 weeks from pre-intervention to post-intervention, and body composition, muscle strength, and explosive power were evaluated 8 weeks before and after the intervention. We also performed an exercise challenge analysis of fatigue biochemical indicators after 8 weeks of intervention. Our results showed that resistance exercise training combined with daily EMS significantly improved muscle mass (p = 0.002) and strength (left, p = 0.007; right, p = 0.002) and significantly reduced body fat (p < 0.001) than the no EMS group. However, there was no significant advantage for biochemical parameters of fatigue and lower body power. In summary, our study demonstrates that 8 weeks of continuous resistance training combined with daily upper body, lower body, and abdominal EMS training can significantly improve muscle mass and upper body muscle strength performance, as well as significantly reduce body fat percentage in healthy subjects.

A comprehensive look at the psychoneuroimmunoendocrinology of spinal cord injury and its progression: mechanisms and clinical opportunities

Spinal cord injury (SCI) is a devastating and disabling medical condition generally caused by a traumatic event (primary injury). This initial trauma is accompanied by a set of biological mechanisms directed to ameliorate neural damage but also exacerbate initial damage (secondary injury). The alterations that occur in the spinal cord have not only local but also systemic consequences and virtually all organs and tissues of the body incur important changes after SCI, explaining the progression and detrimental consequences related to this condition. Psychoneuroimmunoendocrinology (PNIE) is a growing area of research aiming to integrate and explore the interactions among the different systems that compose the human organism, considering the mind and the body as a whole. The initial traumatic event and the consequent neurological disruption trigger immune, endocrine, and multisystem dysfunction, which in turn affect the patient's psyche and well-being. In the present review, we will explore the most important local and systemic consequences of SCI from a PNIE perspective, defining the changes occurring in each system and how all these mechanisms are interconnected. Finally, potential clinical approaches derived from this knowledge will also be collectively presented with the aim to develop integrative therapies to maximize the clinical management of these patients.

The Physiology of Neurogenic Obesity: Lessons from Spinal Cord Injury Research

BACKGROUND

A spinal cord injury (SCI) from trauma or disease impairs sensorimotor pathways in somatic and autonomic divisions of the nervous system, affecting multiple body systems. Improved medical practices have increased survivability and life expectancy after SCI, allowing for the development of extensive metabolic comorbidities and profound changes in body composition that culminate in prevalent obesity.

SUMMARY

Obesity is the most common cardiometabolic component risk in people living with SCI, with a diagnostic body mass index cutoff of 22 kg/m2 to account for a phenotype of high adiposity and low lean mass. The metameric organization of specific divisions of the nervous system results in level-dependent pathology, with resulting sympathetic decentralization altering physiological functions such as lipolysis, hepatic lipoprotein metabolism, dietary fat absorption, and neuroendocrine signaling. In this manner, SCI provides a unique opportunity to study in vivo the "neurogenic" components of certain pathologies that otherwise are not readily observable in other populations. We discuss the unique physiology of neurogenic obesity after SCI, including the altered functions mentioned above as well as structural changes such as reduced skeletal muscle and bone mass and increased lipid deposition in the adipose tissue, skeletal muscle, bone marrow, and liver.

KEY MESSAGE

The study of neurogenic obesity after SCI gives us a unique neurological perspective on the physiology of obesity. The lessons learned from this field can guide future research and advancements to inform the study of obesity in persons with and without SCI.

Electrical Stimulation Exercise for People with Spinal Cord Injury: A Healthcare Provider Perspective

Electrical stimulation exercise has become an important modality to help improve the mobility and health of individuals with spinal cord injury (SCI). Electrical stimulation is used to stimulate peripheral nerves in the extremities to assist with muscle strengthening or functional activities such as cycling, rowing, and walking. Electrical stimulation of the peripheral nerves in the upper extremities has become a valuable tool for predicting the risk of hand deformities and rehabilitating functional grasping activities. The purpose of this paper is to provide healthcare providers perspective regarding the many rehabilitation uses of electrical stimulation in diagnosing and treating individuals with SCI. Electrical stimulation has been shown to improve functional mobility and overall health, decrease spasticity, decrease the risk of cardiometabolic conditions associated with inactivity, and assist in the diagnosis/prognosis of hand deformities in those with tetraplegia. Studies involving non-invasive stimulation of the spinal nerves via external electrodes aligned with the spinal cord and more invasive stimulation of electrodes implanted in the epidural lining of the spinal cord have demonstrated improvements in the ability to stand and enhanced the stepping pattern during ambulation. Evidence is also available to educate healthcare professionals in using functional electrical stimulation to reduce muscle spasticity and to recognize limitations and barriers to exercise compliance in those with SCI. Further investigation is required to optimize the dose-response relationship between electrical stimulation activities and the mobility and healthcare goals of those with SCI and their healthcare providers.

Impact of rehabilitation on volumetric muscle loss in subjects with traumatic spinal cord injury: A systematic review

BACKGROUND

Spinal cord injury (SCI) leads to spinal nerve fiber tract damage resulting in functional impairments. Volumetric muscle loss (VML), a skeletal muscle volume abnormal reduction, is represented by atrophy below the injury level. The strategies for VML management included personalized approaches, and no definite indications are available.

OBJECTIVE

To identify the rehabilitation effects of VML in subjects with SCI (humans and animals).

METHODS

PubMed, Scopus, and Web of Science databases were systematically searched to identify longitudinal observational studies with individuals affected by traumatic SCI as participants; rehabilitation treatment as intervention; no control, sham treatment, and electrical stimulation programs as control; total lean body and lower limb lean mass, cross-sectional area, functional gait recovery, muscle thickness, and ultrasound intensity, as outcome.

RESULTS

Twenty-four longitudinal observational studies were included, evaluating different rehabilitation approaches' effects on the VML reduction in subjects affected by SCI. The data showed that electrical stimulation and treadmill training are effective in reducing the VML in this population.

CONCLUSION

This systematic review underlines the need to treat subjects with traumatic SCI (humans and animals) with different rehabilitation approaches to prevent VML in the subacute and chronic phases. Further clinical observations are needed to overcome the bias and to define the intervention's timing and modalities.

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.

Effectiveness of Blood Flow Restriction in Neurological Disorders: A Systematic Review

There is scientific evidence that Blood Flow Restriction (BFR) is beneficial in healthy people, the elderly and patients with musculoskeletal disorders. A systematic review was conducted to evaluate the effectiveness of BFR in patients with neurological disorders. The literature search was conducted up until July 2022 in the following databases: PubMed, Web of Science (WOS), Physiotherapy Evidence Database (PEDro), LILACS, Scopus, Cumulative Index of Nursing and Allied Literature Complete (CINAHL), the Cochrane Library and Scientific Electronic Library Online (SciELO). The PEDro scale was used to analyze the methodological quality of the studies, and the Cochrane Collaboration's tool was employed to evaluate the risk of bias. A total of seven articles were included. BFR seems to be beneficial in neurological disorders. Improvements have been found in sensorimotor function, frequency and step length symmetry, perceived exertion, heart rate and gait speed, walking endurance, fatigue, quality of life, muscles thickness, gluteus density and muscle edema. No improvements were found in lower limb strength or balance. However, results must be taken with caution due to the small number of articles and to the large heterogeneity. More clinical trials are needed. These studies should homogenize the protocols used in larger samples, as well as improve their methodological quality.

Muscle adaptations in acute SCI following overground exoskeleton + FES training: A pilot study

Objective

To evaluate the combined effects of robotic exoskeleton and functional electrical stimulation (FES) training on muscle composition during over-ground gait training in persons with acute spinal cord injury (SCI).

Design

Randomized crossover pilot study.

Setting

Inpatient-rehabilitation Hospital.

Participants

Six individuals with acute SCI.

Intervention

Participants were randomized to either receive training with the Ekso® Bionics exoskeleton combined with FES in addition to standard-of-care or standard-of-care alone.

Outcome measures

The main outcome measures for the study were quantified using magnetic resonance imaging (MRI), specifically, lower extremity muscle volume and intramuscular adipose tissue (IMAT). Static balance and fall risk were assessed using the Berg Balance Scale.

Results

Significant improvements were observed in muscle volume in the exoskeleton intervention group when compared to only standard-of-care (p < 0.001). There was no significant difference between the groups in IMAT even though the intervention group saw a reduction in IMAT that trended towards statistical significance (p = 0.07). Static balance improved in both groups, with greater improvements seen in the intervention group.

Conclusions

Early intervention with robotic exoskeleton may contribute to improved muscle function measured using MRI in individuals with acute SCI.

Effects of Electrical Stimulation Training on Body Composition Parameters After Spinal Cord Injury: A Systematic Review

OBJECTIVE

To determine the effects of neuromuscular electrical stimulation (NMES) or functional electrical stimulation (FES), or both, training on different body composition parameters in individuals with spinal cord injury.

DATA SOURCES

Three independent reviewers searched PubMed, Web of Science, Scopus, Cochrane Central, and Virtual Health Library until March 2020.

STUDY SELECTION

Studies were included if they applied NMES/FES on the lower limb muscles after spinal cord injury, reported stimulation parameters (frequency, pulse duration, and amplitude of current), and body composition parameters, which included muscle cross-sectional area (CSA), fat-free mass, lean mass (LM), fat mass, visceral adipose tissue, and intramuscular fat.

DATA SYNTHESIS

A total of 46 studies were included in the final analysis with a total sample size of 414 subjects. NMES loading exercise and FES cycling exercise were commonly used for training. Increases in muscle CSA ranged from 5.7-75%, with an average of 26% (n=33). Fifteen studies reported changes (both increase and decrease) in LM or fat-free mas ranged from -4% to 35%, with an average of less than 5%. Changes in fat mass (n=10) were modest. The effect on ectopic adipose tissue is inconclusive, with 2 studies showing an average reduction in intramuscular fat by 9.9%. Stimulation parameters ranged from 200-1000 μs for pulse duration, 2-60 Hz for the frequency, and 10-200 mA in amplitude. Finally, increase in weekly training volumes after NMES loading exercise resulted in a remarkable increase in percentage changes in LM or muscle CSA.

CONCLUSIONS

NMES/FES is an effective rehabilitation strategy for muscle hypertrophy and increasing LM. Weekly training volumes are associated with muscle hypertrophy after NMES loading exercise. Furthermore, positive muscle adaptations occur despite the applied stimulation parameters. Finally, the included studies reported wide range of stimulation parameters without reporting rationale for such selection.

Protocols aiming to increase muscle mass in persons with motor complete spinal cord injury: a systematic review

PURPOSE

The purpose of this review was to compare all intervention modalities aimed at increasing skeletal muscle mass (SMM) in the paralysed limbs of persons with chronic (>1-year post-injury), motor complete spinal cord injury (SCI).

MATERIALS AND METHODS

A systematic review of EMBASE, MEDLINE, Scopus, and SPORTDiscus databases was conducted from inception until December 2021. Published intervention studies aimed to increase SMM (measured by magnetic resonance imaging, computed tomography, ultrasound, muscle biopsy, or lean soft tissue mass by dual X-ray absorptiometry) in the paralysed limbs of adults (>18 years) with SCI were included.

RESULTS

Fifty articles were included that, overall, demonstrated a high risk of bias. Studies were categorised into six groups: neuromuscular electrical stimulation (NMES) with and without external resistance, functional electrical stimulation cycling, walking- and standing-based interventions, pharmacological treatments, and studies that compared or combined intervention modalities. Resistance training (RT) using NMES on the quadriceps produced the largest and most consistent increases in SMM of all intervention modalities.

CONCLUSIONS

Current evidence suggests that clinical practise aiming to increase SMM in the paralysed limbs of persons with motor complete SCI should perform NMES-RT. However, more high-quality randomised control trials are needed to determine how training variables, such as exercise volume and intensity, can be optimised for increasing SMM. Implications for rehabilitationPersons with spinal cord injury (SCI) experience severe reductions in skeletal muscle mass (SMM) post-injury, which may exacerbate their risk of obesity and metabolic disease.Out of all exercise and non-exercise-based interventions, this systematic review shows that neuromuscular electrical stimulation-based resistance training demonstrates the most robust and consistent evidence for increasing skeletal muscle mass in the paralysed limbs of adults with motor complete spinal cord injury.The findings from this review can be used to inform evidence-based practise for exercise practitioners, as well as direct future research focused on increasing muscle mass in this population.

Effects of functional electrical stimulation on muscle health after spinal cord injury

Spinal cord injury is a devastating condition interrupting voluntary movement and motor control. In response to unloading, skeletal muscle undergoes numerous adaptations, including rapid and profound atrophy, intramuscular fat accumulation, impaired muscular glucose metabolism and decreased force generation and muscle performance. Functional electrical stimulation (FES) involves electrically stimulating affected muscles to contract in a coordinated manner to create a functional movement or task. Effects of FES-cycling, rowing and resistance training on muscle health are described here. Briefly, FES-cycling and resistance training may slow muscle atrophy or facilitate muscle hypertrophy, and all modalities benefit muscle composition and performance to some extent. These interventions show promise as future rehabilitative tools after spinal cord injury.

Effects of functional electro-stimulation combined with blood flow restriction in affected muscles by spinal cord injury

Muscle atrophy is a great consequence of spinal cord injuries (SCI) due to immobility. SCI's detrimental effects on large muscle groups may lead to secondary effects such as glucose intolerance, increased risk of metabolic syndrome, and diabetes. Exercising with blood flow restriction (BFR) has been proposed as an effective method to induce hypertrophy using low training loads, with little or no muscle damage. This study investigated acute and chronic effects of low-intensity functional electrical stimulation (FES) combined with BFR on muscles affected by spinal cord injury. The acute effects of one bout of FES with (FES + BFR group) and without BFR (FES group) on muscle thickness (MT) and edema formation were compared. The chronic effects on MT and edema following 8 weeks of twice weekly training with and without BFR were also compared. The FES + BFR group showed MT and edema increases compared to the FES only group (p< 0.05). The FES + BFR showed a chronic MT increase after 4 weeks of training (p <0.05), with no further MT increases from the 4th to the 8th week (p>0.05). Following 3 weeks of detraining, MT decreased to baseline. No MT changes were observed in the FES (p>0.05). The FES + BF stimuli induced MT increases on the paralyzed skeletal muscles of SCI. The acute effects suggest that FES causes a greater metabolite accumulation and edema when combined with BFR. The early increases in MT can be attributed to edema, whereas after the 4th week, it is likely to be related to muscle hypertrophy. Register Clinical Trial Number on ReBeC: RBR-386rm8.

Neurogenic Obesity-Induced Insulin Resistance and Type 2 Diabetes Mellitus in Chronic Spinal Cord Injury

The population with SCI is at a significant risk for both insulin resistance and type 2 diabetes mellitus (T2DM) secondary to neurogenic obesity. The prevalence of insulin resistance and T2DM in persons with SCI suggests that disorders of carbohydrate metabolism are at epidemic proportions within the population. However, the true frequency of such disorders may be underestimated because biomarkers of insulin resistance and T2DM used from the population without SCI remain nonspecific and may in fact fail to identify true cases that would benefit from intervention. Furthermore, diet and exercise have been used to help mitigate neurogenic obesity, but results on disorders of carbohydrate metabolism remain inconsistent, likely because of the various ways carbohydrate metabolism is assessed. The objective of this article is to review current literature on the prevalence and likely mechanisms driving insulin resistance and T2DM in persons with SCI. This article also explores the various assessments and diagnostic criteria used for insulin resistance and T2DM and briefly discusses the effects of exercise and/or diet to mitigate disorders of carbohydrate metabolism brought on by neurogenic obesity.

Flexibility of equine bioenergetics and muscle plasticity in response to different types of training: An integrative approach, questioning existing paradigms

Equine bioenergetics have predominantly been studied focusing on glycogen and fatty acids. Combining omics with conventional techniques allows for an integrative approach to broadly explore and identify important biomolecules. Friesian horses were aquatrained (n = 5) or dry treadmill trained (n = 7) (8 weeks) and monitored for: evolution of muscle diameter in response to aquatraining and dry treadmill training, fiber type composition and fiber cross-sectional area of the M. pectoralis, M. vastus lateralis and M. semitendinosus and untargeted metabolomics of the M. pectoralis and M. vastus lateralis in response to dry treadmill training. Aquatraining was superior to dry treadmill training to increase muscle diameter in the hindquarters, with maximum effect after 4 weeks. After dry treadmill training, the M. pectoralis showed increased muscle diameter, more type I fibers, decreased fiber mean cross sectional area, and an upregulated oxidative metabolic profile: increased β-oxidation (key metabolites: decreased long chain fatty acids and increased long chain acylcarnitines), TCA activity (intermediates including succinyl-carnitine and 2-methylcitrate), amino acid metabolism (glutamine, aromatic amino acids, serine, urea cycle metabolites such as proline, arginine and ornithine) and xenobiotic metabolism (especially p-cresol glucuronide). The M. vastus lateralis expanded its fast twitch profile, with decreased muscle diameter, type I fibers and an upregulation of glycolytic and pentose phosphate pathway activity, and increased branched-chain and aromatic amino acid metabolism (cis-urocanate, carnosine, homocarnosine, tyrosine, tryptophan, p-cresol-glucuronide, serine, methionine, cysteine, proline and ornithine). Trained Friesians showed increased collagen and elastin turn-over. Results show that branched-chain amino acids, aromatic amino acids and microbiome-derived xenobiotics need further study in horses. They feed the TCA cycle at steps further downstream from acetyl CoA and most likely, they are oxidized in type IIA fibers, the predominant fiber type of the horse. These study results underline the importance of reviewing existing paradigms on equine bioenergetics.

Body composition assessment in athletes with physical impairment who have been practicing a wheelchair sport regularly and for a prolonged period

BACKGROUND

Today several important aspects related to the impact of long-term wheelchair sports on whole-body and regional body composition in athletes with a physical impairment are poorly understood.

OBJECTIVE

This cross-sectional study aimed at investigating the impact of the long-term regular practice of wheelchair sports on body composition in male wheelchair athletes (WA) as compared with both non-athletic participants with a physical impairment and non-athletic able-bodied participants.

METHODS

Nine WA were each matched pairwise by age, duration of injury and body mass index (BMI) with a participant with a physical impairment not engaged in any wheelchair sport (N-WA) and by age and BMI with an able-bodied (AB) participant. Whole-body and regional bone mineral content (BMC), fat-free soft tissue mass (FFSTM), fat mass (FM) and percentage FM (%FM) were assessed by means of Dual-Energy X-ray Absorptiometry.

RESULTS

WA had significantly lower FM and %FM vs. N-WA at the whole-body level (P = 0.01 for both) and in the trunk region (P = 0.001 and P = <0.001, respectively). The only difference in body composition variables between WA and AB was found in the legs where WA had significantly higher FM (P = 0.014) along with lower BMC (P = 0.009) and FFSTM (P = 0.005) vs. AB in the legs.

CONCLUSIONS

The results of the present study showed that the regular, long-term practice of wheelchair sport may be associated with beneficial body composition adaptations in athletes with a physical impairment at the whole-body and trunk level.

Skeletal muscle hypertrophy and attenuation of cardio-metabolic risk factors (SHARC) using functional electrical stimulation-lower extremity cycling in persons with spinal cord injury: study protocol for a randomized clinical trial

Background

Persons with spinal cord injury (SCI) are at heightened risks of developing unfavorable cardiometabolic consequences due to physical inactivity. Functional electrical stimulation (FES) and surface neuromuscular electrical stimulation (NMES)-resistance training (RT) have emerged as effective rehabilitation methods that can exercise muscles below the level of injury and attenuate cardio-metabolic risk factors. Our aims are to determine the impact of 12 weeks of NMES + 12 weeks of FES-lower extremity cycling (LEC) compared to 12 weeks of passive movement + 12 weeks of FES-LEC on: (1) oxygen uptake (VO₂), insulin sensitivity, and glucose disposal in adults with SCI; (2) skeletal muscle size, intramuscular fat (IMF), and visceral adipose tissue (VAT); and (3) protein expression of energy metabolism, protein molecules involved in insulin signaling, muscle hypertrophy, and oxygen uptake and electron transport chain (ETC) activities.

Methods/Design

Forty-eight persons aged 18–65 years with chronic (> 1 year) SCI/D (AIS A-C) at the C5-L2 levels, equally sub-grouped by cervical or sub-cervical injury levels and time since injury, will be randomized into either the NMES + FES group or Passive + FES (control group). The NMES + FES group will undergo 12 weeks of evoked RT using twice-weekly NMES and ankle weights followed by twice-weekly progressive FES-LEC for an additional 12 weeks. The control group will undergo 12 weeks of passive movement followed by 12 weeks of progressive FES-LEC. Measurements will be performed at baseline (B; week 0), post-intervention 1 (P1; week 13), and post-intervention 2 (P2; week 25), and will include: VO₂ measurements, insulin sensitivity, and glucose effectiveness using intravenous glucose tolerance test; magnetic resonance imaging to measure muscle, IMF, and VAT areas; muscle biopsy to measure protein expression and intracellular signaling; and mitochondrial ETC function.

Discussion

Training through NMES + RT may evoke muscle hypertrophy and positively impact oxygen uptake, insulin sensitivity, and glucose effectiveness. This may result in beneficial outcomes on metabolic activity, body composition profile, mitochondrial ETC, and intracellular signaling related to insulin action and muscle hypertrophy. In the future, NMES-RT may be added to FES-LEC to improve the workloads achieved in the rehabilitation of persons with SCI and further decrease muscle wasting and cardio-metabolic risks.

Trial registration

ClinicalTrials.gov, NCT02660073. Registered on 21 Jan 2016.

Combination of treadmill exercise with bone marrow stromal cells transplantation activates protein synthesis-related molecules in soleus muscle of the spinal cord injured rats

The present study investigated whether treadmill exercise with bone marrow stromal cells (BMSCs) transplantation increase expression level of protein synthesis-related molecules in the soleus muscle after spinal cord injury (SCI). The spinal cord contusion injury was performed at the T9-10 level using the impactor (10 g×25 mm). BMSCs were cultured from femur and tibia of 4-week-old rats and then transplanted directly into the lesion 1-week post injury. The rats in exercise group were walking on treadmill device for 6 days per a week during 6 weeks. Prepared soleus muscles were used for examining mechanisms of protein synthesis after SCI. Myostatin induction level was increased by SCI, but BMSCs engrafting after SCI decreased compared to SCI group. Combination of treadmill exercise with BMSCs showed more potent decrement on myostatin expression. Protein kinase B (Akt) and mammalian target of rapamycin (mTOR) levels were significantly increased in SCI and BMSCs transplantation group compared to SCI group. Combination of treadmill exercise with BMSCs further facilitated expression levels of Akt and mTOR. Insulin-like growth factor-I (IGF-I) and phosphorylated cyclic adenosine monophosphate response element-binding protein (p-CREB) induction levels were more increased in SCI and BMSC transplantation group compared to SCI group. Combination of treadmill exercise with BMSCs further increased expression levels of IGF-I and p-CREB, although statistical significance was not appeared. Combining treadmill exercise with BMSCs transplantation might accelerate protein synthesis and hypertrophy in the soleus muscle after SCI through activation of IGF-I/mTOR signaling pathway.

Ambulation and physical function after eccentric resistance training in adults with incomplete spinal cord injury: A feasibility study

Background: Strengthening the lower extremities has shown to positively influence walking mechanics in those with neurological deficiencies. Eccentric resistance training (ERT) is a potent stimulus for the development of muscular strength with low metabolic demand. Thereby, ERT may benefit those with incomplete spinal cord injuries (iSCI) seeking to improve ambulatory capacity. Design: This study was aimed to determine the effect of ERT on walking speed, mobility, independence, and at home function following iSCI. Methods: Individuals with longstanding iSCI trained twice a week for 12 weeks on an eccentrically biased recumbent stepper. Outcome measures: Walking speed (10 meter walk test; 10MWT), mobility (timed up and go), independence (Walking Index for Spinal Cord Injury; WISCI), and at home function (Spinal Cord Independence Measure; SCIM) were assessed at baseline, after 6 weeks, and after 12 weeks of ERT. Results: There were improvements in walking mobility (158.36 + 165.84 seconds to 56.31 + 42.42 seconds, P = .034, d = 0.62), speed (0.34 + 0.42  m/s to 0.43 + 0.50  m/s, P = .005, d = .23), and independence (8 + 7 to 13 + 7, P = .004, d = .73) after 12 weeks of ERT. At home function remained unchanged (22 + 10 to 24 + 10, P = .10, d = .12). Conclusions: Improving lower extremity strength translated to walking performance and independence in those with iSCI. Additionally, ERT may diminish therapist burden in programs designed to improve ambulatory capacity or strength in those with iSCI.

Effects of 10-week walking and walking with home-based resistance training on muscle quality, muscle size, and physical functional tests in healthy older individuals

Background

Older individuals have been shown to present muscle atrophy in conjunction with increased fat fraction in some muscles. The proportion of fat and connective tissue within the skeletal muscle can be estimated from axial B-mode ultrasound images using echo intensity (EI). EI was used to calculate the index of muscle quality. Walking, home-based weight-bearing resistance training, and its combinations are considered simple, easy, and practical exercise interventions for older adults. The purpose of this study was to quantify the effects of walking and walking with home-based resistance training on muscle quality of older individuals.

Methods

Thirty-one participants performed walking training only (W-group; 72 ± 5 years) and 33 participants performed walking and home-based resistance training (WR-group; 73 ± 6 years). This study was a non-randomized controlled trial with no control group. All participants were instructed to walk 2 or 3 sets per week for 10 weeks (one set: 30-min continuous walking). In addition, the WR-group performed home-based weight-bearing resistance training. EI was measured as a muscle quality index using axial B-mode ultrasound images of the rectus femoris and vastus lateralis of the mid-thigh. We further averaged these parameters to obtain the EI of the quadriceps femoris (QF). Participants further performed five functional tests: sit-ups, supine up, sit-to-stand, 5-m maximal walk, and 6-min walk.

Results

QF EI was significantly decreased in both groups after training (W-group 69.9 ± 7.4 a.u. to 61.7 ± 7.0 a.u., WR-group 64.0 ± 9.5 a.u. to 51.1 ± 10.0 a.u.; P < 0.05), suggesting improved muscle quality. QF EI was further decreased in the WR-group compared with the W-group. The sit-up test in both groups and the sit-to-stand and 5-m maximal walk tests in the W-group were significantly improved after training.

Conclusion

These results suggest that training-induced stimulation is associated with a decrease in EI in some thigh regions. Furthermore, the addition of home-based resistance training to walking would be effective for a greater reduction of EI.

Nutritional status in chronic spinal cord injury: a systematic review and meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVES

The objective was to investigate nutritional status in chronic spinal cord injury (SCI), and compare macronutrient and micronutrient intake to the recommended values by the United States Department of Agriculture (USDA) 2015-2020 Dietary Guidelines for Americans.

SETTING

United States of America.

METHODS

A MEDLINE/PubMed, Google Scholar, Scopus, and Web of Science search was performed, identifying 268 papers. All papers included were English-language papers examining adults with chronic SCI. A meta-analysis was performed to produce weighted averages and 95% confidence intervals (CI) when summary statistics were provided.

RESULTS

The systematic review included 15 articles, while the meta-analysis included 12. Resting metabolic rate (1492 kcal/day; CI: 1414-1569) fell below the able-bodied average, and total energy (1876 kcal/day; CI: 1694-2059) and fiber (17 g/day; CI: 14-20) intake were below USDA guidelines. Protein (319 kcal/day; CI: 294-345) and carbohydrate (969 kcal/day; CI: 851-1087) intake were above guidelines. Fat intake (663 kcal/day; CI: 590-736) was within USDA guidelines. Vitamins A, B5, B7, B9, D, E, potassium, and calcium were deficient, while vitamins B1, B2, B3, B12, C, K, sodium, phosphorus, copper, and zinc were in excess according to USDA guidelines. Vitamin B6, iron, and magnesium were within USDA guidelines.

CONCLUSION

Findings indicate greater energy intake relative to energy needs in those with chronic SCI, and an imbalance in fiber intake and micronutrients compared to the USDA guidelines. Future research examining nutritional health status is needed in order to establish evidence-based, SCI-specific dietary guidelines.

Paralytic and nonparalytic muscle adaptations to exercise training versus high-protein diet in individuals with long-standing spinal cord injury

This study compares the effects of an 8-wk isocaloric high-protein (HP) diet versus a combination exercise (Comb-Ex) regimen on paralytic vastus lateralis (VL) and nonparalytic deltoid muscle in individuals with long-standing spinal cord injury (SCI). Fiber-type distribution, cross-sectional area (CSA), levels of translation initiation signaling proteins (Erk-1/2, Akt, p70S6K1, 4EBP1, RPS6, and FAK), and lean thigh mass were analyzed at baseline and after the 8-wk interventions. A total of 11 participants (C5-T12 levels, 21.8 ± 6.3 yr postinjury; 6 Comb-Ex and 5 HP diet) completed the study. Comb-Ex training occurred 3 days/wk and consisted of upper body resistance training (RT) in addition to neuromuscular electrical stimulation (NMES)-induced-RT for paralytic VL muscle. Strength training was combined with high-intensity arm-cranking exercises (1-min intervals at 85-90%, V̇o2peak) for improving cardiovascular endurance. For the HP diet intervention, protein and fat each comprised 30%, and carbohydrate comprised 40% of total energy. Clinical tests and muscle biopsies were performed 24 h before and after the last exercise or diet session. The Comb-Ex intervention increased Type IIa myofiber distribution and CSA in VL muscle and Type I and IIa myofiber CSA in deltoid muscle. In addition, Comb-Ex increased lean thigh mass, V̇o2peak, and upper body strength ( P < 0.05). These results suggest that exercise training is required to promote favorable changes in paralytic and nonparalytic muscles in individuals with long-standing SCI, and adequate dietary protein consumption alone may not be sufficient to ameliorate debilitating effects of paralysis. NEW & NOTEWORTHY This study is the first to directly compare the effects of an isocaloric high-protein diet and combination exercise training on clinical and molecular changes in paralytic and nonparalytic muscles of individuals with long-standing spinal cord injury. Our results demonstrated that muscle growth and fiber-type alterations can best be achieved when the paralyzed muscle is sufficiently loaded via neuromuscular electrical stimulation-induced resistance training.

Anthropometry, Body Composition, and Performance in Sport-Specific Field Test in Female Wheelchair Basketball Players

Data on the physical and performance characteristics of female wheelchair basketball (WB) players are scarce. In several countries female WB players train and compete with male players on mixed teams due to the limited total population of players, which would otherwise lead to large territorial spread for each team. Any differences in terms of physical characteristics and/or WB skill proficiency between male and female WB players would be relevant to team performance in mixed teams. This work examined anthropometry, body composition, and performance in a set of sport-specific field tests in a sample of 13 female WB players representing about 40% of the eligible population in Italy across a range of functional point scores (Point). Point is assigned on an ordinal scale from 1.0 (i.e., players with minimal functional potential) through to 4.5 (players with maximum functional potential). Our female sample was then compared against twice as many (n = 26) Point-matched (±0.5 points) male players. The two groups were similar for age (P = 0.191; effect size [d] = 0.2), self-reported duration of injury (P = 0.144, d = 0.6), WB experience (P = 0.178, d = 0.5), and volume of training (P = 0.293, d = 0.4). The large majority of measured linear anthropometric variables (10/13) were lower in female players than males (0.001 < P ≤ 0.041). Skinfold-estimated percent body fat was higher (+7.6%) in females (30.7 ± 6.0%; P < 0.001, d = 1.3). Mean performance was worse in female than in males in six out of seven sport-specific field tests, scores being significantly lower in females for the maximal pass (7.5 ± 2.0 m for females vs. 10.4 ± 2.8 m for males; P = 0.002, d = 1.2) and suicide tests (55.8 ± 6.4 s for females vs. 45.4 ± 6.7 s for males; P < 0.001, d = 1.6). When performance in subgroups of females (n = 9) chosen across a range of Point was compared with that of males assigned 1.0 or 1.5 Point less (each n = 9), performance differences between male and female WB players were partially and completely eliminated, respectively. This work contributed new data for characterizing the physique and performance of female WB players. Further, the results suggested that when male and female athletes compete together in mixed teams, a 1.5 points subtraction from female players is needed to match the real gender difference in performance.

Cross-cultural validation of a Brazilian version of the adapted manual wheelchair circuit (AMWC-Brazil)

Purpose: To translate, culturally adapt and validate the Adapted Manual Wheelchair Circuit (AMWC) into Brazilian-Portuguese. Design: Cross-sectional study. Methods: Sixty-six men (median age of 30.5 years [percentiles 25 and 75: 24.0; 38.3 years]) with traumatic spinal cord injury were consecutively enrolled and divided into two groups: tetraplegia (TP) and paraplegia (PP). The participants performed the AMWC-Brazil and were evaluated by the Spinal Cord Injury Measure version III (SCIM-III). Translation, translation synthesis, back-translation, committee review and construct validity were adopted for the cross-cultural adaptation. Construct validity was performed by testing whether the test scores were significantly correlated (Spearman's correlation coefficient) to the subjects' injury level, age, time since injury, body mass index (BMI) and SCIM-III scale. Results: All the AMWC-Brazil's outcomes were significantly correlated with SCIM-III total score and subscales (P ≤ 0.01). However, when the analyses were stratified over injury level, only the TP showed a high correlation between the AMWC-Brazil's outcomes and the SCIM-III. For construct validity, 4 of 5 hypotheses were confirmed. Only BMI was not a significant predictor of the AMWC-Brazil outcomes. Conclusion: The AMWC was successfully translated to the Brazilian-Portuguese (AMWC-Brazil) and presented high and satisfactory construct validity.

Paradigms of Lower Extremity Electrical Stimulation Training After Spinal Cord Injury

Skeletal muscle atrophy, increased adiposity and reduced physical activity are key changes observed after spinal cord injury (SCI) and are associated with numerous cardiometabolic health consequences. These changes are likely to increase the risk of developing chronic secondary conditions and impact the quality of life in persons with SCI. Surface neuromuscular electrical stimulation evoked resistance training (NMES-RT) was developed as a strategy to attenuate the process of skeletal muscle atrophy, decrease ectopic adiposity, improve insulin sensitivity and enhance mitochondrial capacity. However, NMES-RT is limited to only a single muscle group. Involving multiple muscle groups of the lower extremities may maximize the health benefits of training. Functional electrical stimulation-lower extremity cycling (FES-LEC) allows for the activation of 6 muscle groups, which is likely to evoke greater metabolic and cardiovascular adaptation. Appropriate knowledge of the stimulation parameters is key to maximizing the outcomes of electrical stimulation training in persons with SCI. Adopting strategies for long-term use of NMES-RT and FES-LEC during rehabilitation may maintain the integrity of the musculoskeletal system, a pre-requisite for clinical trials aiming to restore walking after injury. The current manuscript presents a combined protocol using NMES-RT prior to FES-LEC. We hypothesize that muscles conditioned for 12 weeks prior to cycling will be capable of generating greater power, cycle against higher resistance and result in greater adaptation in persons with SCI.

A feasibility pilot using telehealth videoconference monitoring of home-based NMES resistance training in persons with spinal cord injury

INTRODUCTION

The objective of the study was to investigate the feasibility and initial efficacy of telehealth communication in conjunction with surface neuromuscular electrical stimulation (NMES) resistance training (RT) to induce muscle hypertrophy.

MATERIALS AND METHODS

This was a home-based setting of within-subject control design of trained vs controlled limbs. Five men with chronic (>1 year postinjury) motor-complete spinal cord injury (SCI) participated in a twice-weekly telehealth videoconference program using home-based NMES-RT for 8 weeks. Stimulation was applied to the knee extensor muscle group of the trained leg, while the untrained leg served as a control. Participants received real-time feedback to ensure a proper setup of electrodes and stimulator to monitor subject safety throughout the entire training session. Magnetic resonance imaging was used to measure cross-sectional areas (CSAs) and intramuscular fat (IMF) of the whole thigh and individual muscle groups. Average two-way travel time, distance traveled in miles and total cost of gas per mile were calculated.

RESULTS

Participants had 100% compliance. Trained whole and absolute knee extensor muscle CSA increased by 13% (P=0.002) and 18% (P=0.0002), with no changes in the controlled limb. Absolute knee flexor and adductor CSAs increased by 3% (P=0.02) and 13% (P=0.0001), respectively. Absolute whole thigh and knee extensor IMF CSAs decreased significantly in the trained limb by 14% (P=0.01) and 36% (P=0.0005), respectively, with no changes in controlled limb.

DISCUSSION

The pilot work documented that using telehealth communication is a safe, feasible and potentially cost-reducing approach for monitoring home-based NMES-RT in persons with chronic SCI. All trained muscles showed detectable muscle hypertrophy with concomitant decrease in ectopic adipose tissue.

Effects of Testosterone and Evoked Resistance Exercise after Spinal Cord Injury (TEREX-SCI): study protocol for a randomised controlled trial

INTRODUCTION

Individuals with spinal cord injury (SCI) are at a lifelong risk of obesity and chronic metabolic disorders including insulin resistance and dyslipidemia. Within a few weeks of injury, there is a significant decline in whole body fat-free mass, particularly lower extremity skeletal muscle mass, and subsequent increase in fat mass (FM). This is accompanied by a decrease in anabolic hormones including testosterone. Testosterone replacement therapy (TRT) has been shown to increase skeletal muscle mass and improve metabolic profile. Additionally, resistance training (RT) has been shown to increase lean mass and reduce metabolic disturbances in SCI and other clinical populations.

METHODS AND ANALYSIS

26 individuals with chronic, motor complete SCI between 18 and 50 years old were randomly assigned to a RT+TRT group (n=13) or a TRT group (n=13). 22 participants completed the initial 16-week training phase of the study and 4 participants withdrew. 12 participants of the 22 completed 16 weeks of detraining. The TRT was provided via transdermal testosterone patches (4-6 mg/day). The RT+TRT group had 16 weeks of supervised unilateral progressive RT using surface neuromuscular electrical stimulation with ankle weights. This study will investigate the effects of evoked RT+TRT or TRT alone on body composition (muscle cross-sectional area, visceral adipose tissue, %FM) and metabolic profile (glucose and lipid metabolism) in individuals with motor complete SCI. Findings from this study may help in designing exercise therapies to alleviate the deterioration in body composition after SCI and decrease the incidence of metabolic disorders in this clinical population.

ETHICS AND DISSEMINATION

The study is currently approved by the McGuire VA Medical Center and Virginia Commonwealth University. All participants read and signed approved consent forms. Results will be submitted to peer-reviewed journals and presented at national and international conferences.

TRIAL REGISTRATION NUMBER

Pre-result, NCT01652040.

Anthropometric prediction of skeletal muscle cross-sectional area in persons with spinal cord injury

Finding an accurate and affordable method to quantify muscle size following spinal cord injury (SCI) could provide benefits clinically and in research settings. The purpose of this study was to validate the use of anthropometric measurements vs. magnetic resonance imaging (MRI) to evaluate muscle cross-sectional area (CSA) and develop a field equation to predict muscle CSA specific to the SCI population. Twenty-two men with chronic (>1 yr) motor complete SCI participated in the current study. Anthropometric measurements, including midthigh circumference and anterior skinfold thickness (SF_T), were taken on the right thigh. The anthropometric muscle cross-sectional area (muscle CSA_anthro) was predicted using the following equation: muscle CSA_anthro = π[r - (SF_T/2)]², where r = thigh circumference/2π. MRI analysis yielded whole thigh CSA (thigh CSA_MRI), midthigh muscle CSA (muscle CSA_MRI), midthigh absolute muscle CSA after subtracting intramuscular fat and bone (muscle CSA-IMF_MRI), subcutaneous adipose tissue (SAT_T) measured at one site as well as at four sites, and bone CSA. Anthropometric measurements were correlated to the thigh CSA_MRI [r² = 0.90, standard error of the estimate (SEE) = 17.6 cm², P < 0.001]. Muscle CSA_anthro was correlated to muscle CSA_MRI (r² = 0.78, SEE = 16.6 cm², P < 0.001) and muscle CSA-IMF_MRI (r² = 0.75, SEE = 17.6 cm², P < 0.001). A single SF_T was correlated to the polar four-site SAT_T (r² = 0.78, SEE = 0.37 cm, P < 0.001). The average femur CSA and average IMF CSA derived from MRI led to the following field equation: muscle CSA_predicted = π[(Thigh_circum/2π) - (SF_T/2)]² - 23.2. Anthropometric measurements of muscle CSA exhibited a good agreement with the gold standard MRI method and led to the development of a field equation for clinical use after accounting for bone and IMF.NEW & NOTEWORTHY This study used anthropometric measurements and magnetic resonance imaging (MRI) to evaluate muscle cross-sectional area (CSA) and developed a field equation to predict thigh muscle CSA specific to the spinal cord-injured (SCI) population. Anthropometric measurements were correlated to the whole thigh CSA and muscle CSA as measured by MRI_. The correlations led to the development of a SCI-specific field equation that accounted for intramuscular fat and bone areas.

Endurance neuromuscular electrical stimulation training improves skeletal muscle oxidative capacity in individuals with motor-complete spinal cord injury

INTRODUCTION

Spinal cord injury (SCI) results in skeletal muscle atrophy, increases in intramuscular fat, and reductions in skeletal muscle oxidative capacity. Endurance training elicited with neuromuscular electrical stimulation (NMES) may reverse these changes and lead to improvement in muscle metabolic health.

METHODS

Fourteen participants with complete SCI performed 16 weeks of home-based endurance NMES training of knee extensor muscles. Skeletal muscle oxidative capacity, muscle composition, and blood metabolic and lipid profiles were assessed pre- and post-training.

RESULTS

There was an increase in number of contractions performed throughout the duration of training. The average improvement in skeletal muscle oxidative capacity was 119%, ranging from -14% to 387% (P = 0.019). There were no changes in muscle composition or blood metabolic and lipid profiles.

CONCLUSION

Endurance training improved skeletal muscle oxidative capacity, but endurance NMES of knee extensor muscles did not change blood metabolic and lipid profiles. Muscle Nerve 55: 669-675, 2017.

Quantification of intermuscular and intramuscular adipose tissue using magnetic resonance imaging after neurodegenerative disorders

Ectopic adiposity has gained considerable attention because of its tight association with metabolic and cardiovascular health in persons with spinal cord injury (SCI). Ectopic adiposity is characterized by the storage of adipose tissue in non-subcutaneous sites. Magnetic resonance imaging (MRI) has proven to be an effective tool in quantifying ectopic adiposity and provides the opportunity to measure different adipose depots including intermuscular adipose tissue (IMAT) and intramuscular adipose tissue (IntraMAT) or intramuscular fat (IMF). It is highly important to distinguish and clearly define these compartments, because controversy still exists on how to accurately quantify these adipose depots. Investigators have relied on separating muscle from fat pixels based on their characteristic signal intensities. A common technique is plotting a threshold histogram that clearly separates between muscle and fat peaks. The cut-offs to separate between muscle and fat peaks are still not clearly defined and different cut-offs have been identified. This review will outline and compare the Midpoint and Otsu techniques, two methods used to determine the threshold between muscle and fat pixels on T1 weighted MRI. The process of water/fat segmentation using the Dixon method will also be outlined. We are hopeful that this review will trigger more research towards accurately quantifying ectopic adiposity due to its high relevance to cardiometabolic health after SCI.

Effects of functional electrical stimulation assisted rowing on aerobic fitness and shoulder pain in manual wheelchair users with spinal cord injury

OBJECTIVE

Test the effectiveness of a 6-week functional electrical stimulation (FES)-assisted rowing intervention to increase aerobic fitness and decrease shoulder pain in manual wheelchair users with spinal cord injury (SCI) Methods: Ten adults with SCI (47 ± 12 years, 86 ± 19.7 kg, 175.5 ± 13.2 cm) 18 ± 14 years since injury, AIS classification A-C who had pain in one or both shoulders for >6 months took part in a pre-test, post-test experiment in our human performance laboratory. Participants took part in 30 minutes of FES-assisted rowing, 3 days/week × 6 weeks. Participants were evaluated for VO₂ peak (FES-row and arm bike), distance rowed, arm power output, Wheelchair User Shoulder Pain Index (WUSPI), upper extremity isokinetic strength, scapular stabilization, participation (LIFE-H), quality of life (QOL-SCI), qualitative exit interview.

RESULTS

Participants increased distance rowed by 257 ± 266 m and increased arm power output by 6.7 ± 7.9 W. An 8% increase in VO₂ peak and 10.5 ± 4.4 point decrease in shoulder pain were observed (all P < 0.05). There were no changes in upper extremity strength, scapular stabilization, or survey-based measures of participation or quality of life. Qualitative interviewing indicated overall enjoyment of the intervention and improvement in perceived quality of life.

CONCLUSIONS

FES-assisted rowing is effective to increase aerobic fitness and decrease shoulder pain in manual wheelchair users with SCI. Further research is necessary to determine if rowing without FES can provide similar benefits, and to determine mechanisms driving improvements in shoulder pain, as no changes in measures of upper extremity strength or scapular stabilization were observed.

Influence of Relative Strength on Functional Independence of Patients With Spinal Cord Injury

OBJECTIVE

To investigate the influence of strength values and fat mass on functional independence of men with different spinal cord injury (SCI) levels.

DESIGN

Cross-sectional study.

SETTING

Hospital network.

PARTICIPANTS

Men with SCI (N=45).

INTERVENTIONS

Subjects were assessed in functional independence scales, a 1 repetition maximum (1RM) test, and body composition to detect absolute and relative strength: 1RM divided by body mass (BM) and lean body mass (LBM), respectively.

MAIN OUTCOME MEASURES

Stepwise multiple regression analysis was used to verify the influence of predictors on functional independence (FIM and Spinal Cord Independence Measure [SCIM] scale and subscales). Receiver operating characteristic curves were created to identify cutoff points of strength for functional independence.

RESULTS

The best models for FIM total, FIM mobility, and SCIM total used 1RM as the best predictor (adjusted R²=.75, .67, and .65, respectively; P<.05). Relative strength (1RM/LBM) was the best predictor for SCIM mobility (adjusted R²=.62, P<.05). A FIM score of 69 has a 1RM cutoff point of 50.1kg, and a FIM score of 76 has cutoff points of .73 for 1RM/BM and .91 for 1RM/LBM. A SCIM score of 68 has cutoff points for 1RM, 1RM/BM, and 1RM/LBM of 50.1kg, .77, and .92, respectively.

CONCLUSIONS

Cutoff points of relative strength should be used as determinant variables for independence, health, or sports performance. This study may contribute to more adequate guidance of physical activity during a rehabilitation program and after discharge.

Neuromuscular electrical stimulation and testosterone did not influence heterotopic ossification size after spinal cord injury: A case series

Neuromuscular electrical stimulation (NMES) and testosterone replacement therapy (TRT) are effective rehabilitation strategies to attenuate muscle atrophy and evoke hypertrophy in persons with spinal cord injury (SCI). However both interventions might increase heterotopic ossification (HO) size in SCI patients. We present the results of two men with chronic traumatic motor complete SCI who also had pre-existing HO and participated in a study investigating the effects of TRT or TRT plus NMES resistance training (RT) on body composition. The 49-year-old male, Subject A, has unilateral HO in his right thigh. The 31-year-old male, Subject B, has bilateral HO in both thighs. Both participants wore transdermal testosterone patches (4-6 mg/d) daily for 16 wk. Subject A also underwent progressive NMES-RT twice weekly for 16 wk. Magnetic resonance imaging scans were acquired prior to and post intervention. Cross-sectional areas (CSA) of the whole thigh and knee extensor skeletal muscles, femoral bone, and HO were measured. In Subject A (NMES-RT + TRT), the whole thigh skeletal muscle CSA increased by 10%, the knee extensor CSA increased by 17%, and the HO + femoral bone CSA did not change. In Subject B (TRT), the whole thigh skeletal muscle CSA increased by 13% in the right thigh and 6% in the left thigh. The knee extensor CSA increased by 7% in the right thigh and did not change in the left thigh. The femoral bone and HO CSAs in both thighs did not change. Both the TRT and NMES-RT + TRT protocols evoked muscle hypertrophy without stimulating the growth of pre-existing HO.

Neuromuscular electrical stimulation training increases intermuscular fascial length but not tendon cross-sectional area after spinal cord injury

OBJECTIVE

To determine the effects of 12 weeks of neuromuscular electrical stimulation (NMES) training with ankle weights on intermuscular fascial length and patellar tendon cross-sectional area (CSA) in persons with spinal cord injury (SCI).

METHODS

This study was a pre-post intervention. Seven men with motor complete SCI were randomly assigned to a resistance training plus diet (RT + diet) group (n = 4) or a diet control group (n = 3). Participants in the RT + diet group were enrolled in a 12-week leg extension weight-lifting program via surface NMES of the knee extensor muscle group. The length of mid-thigh intermuscular fascia and the patellar tendon CSA were measured using MRI.

RESULTS

In the RT + diet group, a nonsignificant 8% increase in the CSA of the patellar tendon (P = .14) was noted. The length of the mid-thigh intermuscular fascia increased by 19% and 23% in the right (P = .029) and left (P = .015) legs, respectively, with no changes in the diet control group. Positive relationships were noted between skeletal muscle CSAs of the whole thigh (r = 0.77, P = .041) and knee extensors (r = 0.76, P = .048) and intermuscular fascial length.

CONCLUSION

The preliminary results suggest that noncontractile connective tissue structures of the knee extensors respond differently to NMES training after SCI. Skeletal muscle hypertrophy is associated with an increase in the intermuscular fascial length.

Neuromuscular Electrical Stimulation-Induced Resistance Training After SCI: A Review of the Dudley Protocol

BACKGROUND

Neuromuscular electrical stimulation (NMES), often referred to as functional electrical stimulation (FES), has been used to activate paralyzed skeletal muscle in people with spinal cord injury (SCI). The goal of NMES has been to reverse some of the dramatic losses in skeletal muscle mass, to stimulate functional improvements in people with incomplete paralysis, and to produce some of the health benefits associated with exercise.

OBJECTIVE

The purpose of this brief review is to describe a quantifiable resistance training form of NMES developed by Gary A. Dudley.

METHODS

People with motor complete SCI were first tested to confirm that an NMES-induced muscle contraction of the quadriceps muscle could be achieved. The contraction stimulus consisted of biphasic pulses at 35 Hz performed with increasing current up to what was needed to produce full knee extension. Four sets of 10 knee extensions were elicited, if possible. Training occurred biweekly for 3 to 6 months, with ankle weights being increased up to an added weight of 9.1 kg if the 40 repetitions could be performed successfully for 2 sessions.

RESULTS

Many participants have performed this protocol without adverse events, and all participants showed progression in the number of repetitions and/or the amount of weight lifted. Large increases in muscle mass occur, averaging 30% to 40%. Additional physiological adaptations to stimulated muscle have also been reported.

CONCLUSIONS

These results demonstrate that the affected skeletal muscle after SCI responds robustly to progressive resistance training many years after injury. Future work with NMES should determine whether gains in lean mass translate to improved health, function, and quality of life.

Chronic activity-based therapy does not improve body composition, insulin-like growth factor-I, adiponectin, or myostatin in persons with spinal cord injury

Spinal cord injury (SCI) induces dramatic changes in body composition including reductions in fat-free mass (FFM) and increases in fat mass (FM).

OBJECTIVE

To examine changes in body composition in response to chronic activity-based therapy (ABT) in persons with SCI.

DESIGN

Longitudinal exercise intervention.

METHODS

Seventeen men and women with SCI (mean age=36.1±11.5 years) completed 6 months of supervised ABT consisting of load bearing, resistance training, locomotor training, and functional electrical stimulation. At baseline and after 3 and 6 months of ABT, body weight, body fat, and FFM were assessed using dual-energy X-ray absorptiometry, and fasting blood samples were obtained to assess changes in insulin-like growth factor-I (IGF-I), adiponectin, and myostatin.

RESULTS

Across all subjects, there was no change (P>0.05) in body weight, percent body fat, or FFM of the leg, arm, or trunk, whereas whole-body FFM declined (P=0.02, 50.4±8.4 to 49.2±7.4 kg). No changes (P=0.21-0.41) were demonstrated in IGF-I, adiponectin, or myostatin during the study.

CONCLUSIONS

Chronic ABT focusing on the lower extremity does not slow muscle atrophy or alter body fat, body mass, or regional depots of FFM in persons with SCI. Further, it does not induce beneficial changes in adiponectin, myostatin, or IGF-I. Alternative exercise-based therapies are needed in SCI to reverse muscle atrophy and minimize the onset of related health risks.

The effects of electrical stimulation on body composition and metabolic profile after spinal cord injury--Part II

Diet and exercise are cornerstones in the management of obesity and associated metabolic complications, including insulin resistance, type 2 diabetes, and disturbances in the lipid profile. However, the role of exercise in managing body composition adaptations and metabolic disorders after spinal cord injury (SCI) is not well established. The current review summarizes evidence about the efficacy of using neuromuscular electrical stimulation or functional electrical stimulation in exercising the paralytic lower extremities to improve body composition and metabolic profile after SCI. There are a number of trials that investigated the effects on muscle cross-sectional area, fat-free mass, and glucose/lipid metabolism. The duration of the intervention in these trials varied from 6 weeks to 24 months. Training frequency ranged from 2 to 5 days/week. Most studies documented significant increases in muscle size but no noticeable changes in adipose tissue. While increases in skeletal muscle size after twice weekly training were greater than those trials that used 3 or 5 days/week, other factors such as differences in the training mode, i.e. resistance versus cycling exercise and pattern of muscle activation may be responsible for this observation. Loading to evoke muscle hypertrophy is a key component in neuromuscular training after SCI. The overall effects on lean mass were modest and did not exceed 10% and the effects of training on trunk or pelvic muscles remain unestablished. Most studies reported improvement in glucose metabolism with the enhancement of insulin sensitivity being the major factor following training. The effect on lipid profile is unclear and warrants further investigation.

Is body weight-support treadmill training effective in increasing muscle trophism after traumatic spinal cord injury? A systematic review

STUDY DESIGN

Systematic review.

OBJECTIVE

To determine the effectiveness of body weight-support treadmill training (BWSTT) for muscle atrophy management in people with spinal cord injury (SCI).

SETTING

Studies from multiple countries were included.

METHODS

The following databases were consulted from January to October 2013: PubMed, Institute for Scientific Information (ISI), Science Direct and Lilacs. The methodological quality of the articles included was classified according to Jovell and Navarro-Rubio.

RESULTS

A total of five studies were included. These studies reported a significant association between BWSTT and increased trophism of the lower limb muscles of humans with SCI, which was observed as an increase in the cross-sectional area. Moreover, improvements in the ability to generate peak torque, contract the knee extensors and ankle plantarflexors with reduction of body weight support were observed after BWSTT.

CONCLUSION

The results were considered inconclusive because of the low methodological quality of the articles, which was because of the absence of sample homogeneity, thereby providing a low level of evidence for clinical practice.

Improving the Efficiency of Electrical Stimulation Activities After Spinal Cord Injury

In order to enhance spinal cord injury (SCI) rehabilitation programs using neuromuscular electrical stimulation (NMES) and functional electrical stimulation (FES) it is important to examine the manner in which muscle fibers are recruited and the dose-response relationship. A review of the literature suggests that premature force decline and early fatigue with NMES and FES activities may be alleviated with decreased current frequency and increased current intensity. Dose-response relationships with NMES and FES are dependent on the goals of interest as reversing muscle atrophy can be achieved with activities 2-3 times per week for 6 or more weeks while increasing bone mass is more limited and requires more intense activity with greater exercise frequency and duration, e.g., 3-5 days per week for at least 6-12 months. The best known protocol to elicit neurological improvement is massed practice activities-based restorative therapies (ABRT) (3-5 h per day for several weeks).

Potential regenerative rehabilitation technology: implications of mechanical stimuli to tissue health

BACKGROUND

Mechanical loads induced through muscle contraction, vibration, or compressive forces are thought to modulate tissue plasticity. With the emergence of regenerative medicine, there is a need to understand the optimal mechanical environment (vibration, load, or muscle force) that promotes cellular health. To our knowledge no mechanical system has been proposed to deliver these isolated mechanical stimuli in human tissue. We present the design, performance, and utilization of a new technology that may be used to study localized mechanical stimuli on human tissues. A servo-controlled vibration and limb loading system were developed and integrated into a single instrument to deliver vibration, compression, or muscle contractile loads to a single limb (tibia) in humans. The accuracy, repeatability, transmissibility, and safety of the mechanical delivery system were evaluated on eight individuals with spinal cord injury (SCI).

FINDINGS

The limb loading system was linear, repeatable, and accurate to less than 5, 1, and 1 percent of full scale, respectively, and transmissibility was excellent. The between session tests on individuals with spinal cord injury (SCI) showed high intra-class correlations (>0.9).

CONCLUSIONS

All tests supported that therapeutic loads can be delivered to a lower limb (tibia) in a safe, accurate, and measureable manner. Future collaborations between engineers and cellular physiologists will be important as research programs strive to determine the optimal mechanical environment for developing cells and tissues in humans.