Cardiorespiratory Effects of Yogic Versus Slow Breathing in Individuals with a Spinal Cord Injury: An Exploratory Cohort Study.

Background: An intricate physiological and pathophysiological connection exists between the heart and lungs, which is especially important in individuals with spinal cord injury (SCI). While an exercise intervention may seem the best approach to leverage this relationship, the prior work has shown that, despite numerous health benefits, regular exercise training does not improve cardiorespiratory control in individuals with SCI. Breath training presents an alternative intervention that is uniquely accessible, with yogic breathing directly engaging linked fluctuations in respiration and cardiovascular control. In addition, there is evidence across a range of populations that regular yogic breathing reduces cardiovascular disease risk. It is possible that the chronic decrease in breathing frequency associated with regular yogic breathing, rather than the specific yogic breathing techniques themselves, is the primary contributor to the observed risk reduction. Methods: Therefore, in 12 individuals with traumatic SCI from C4 to T8, the authors compared Unpaced and conventional 0.083 Hz (Slow) paced breathing with various yogic breathing techniques including: (1) inspiratory-expiratory breath holds (i.e., Kumbhaka or "Box Breathing"), (2) extended exhalation (1:2 duty cycle), and (3) expiratory resistance via throat constriction (i.e., Ujjayi). Beat-to-beat heart rate and blood pressure were measured as well as end-tidal CO2 and O2 saturation were measured. Statistical analysis was performed using a one-way repeated-measures analysis of variance with post hoc pairwise t tests corrected for multiple comparisons. Results: As expected, all slow breathing patterns markedly increased respiratory sinus arrhythmia (RSA) compared with Unpaced in all (n = 12) individuals. More importantly, Ujjayi breathing appeared to improve ventilatory efficiency over Unpaced breathing in individuals with SCI by increasing O2 saturation (97.6% vs. 96.1%; p = 0.042) and tended to decrease end-tidal CO2 (32 mmHg vs. 35 mmHg; p = 0.08). While other slow breathing patterns demonstrated similar effects, only Ujjayi improved RSA while increasing heart rate and improving ventilatory efficiency. Conclusions: Hence, slow breathing per se can result in important cardiorespiratory changes, but the yogic breathing practice of Ujjayi, with glottic throat resistance, may hold the greatest promise for improving cardiorespiratory control in individuals with SCI (CTR ID No. NCT05480618).

Improved pulmonary function is associated with reduced inflammation after hybrid whole-body exercise training in persons with spinal cord injury.

NEW FINDINGS: What is the central question of this study? Does 12 weeks of functional electrical stimulation (FES) rowing exercise training lead to suppressed systemic inflammation and an improvement in pulmonary function in persons with sub-acute spinal cord injury (SCI)? What is the main finding and its importance? Twelve weeks of FES rowing exercise improves pulmonary function and the magnitude of improvement is associated with reductions in inflammatory biomarkers. Thus, interventions targeting inflammation may lead to better pulmonary outcomes for person with sub-acute SCI. ABSTRACT: The current study was designed to test the hypotheses that (1) reducing systemic inflammation via a 12-week functional electrical stimulation rowing exercise training (FESRT) prescription results in augmented pulmonary function, and (2) the magnitude of improvement in pulmonary function is inversely associated with the magnitude of systemic inflammation suppression in persons with sub-acute (≤2 years) spinal cord injury (SCI). We conducted a retrospective analysis of a randomized controlled trial (NCT#02139436). Twenty-one participants were enrolled (standard of care (SOC; n = 9) or FESRT (n = 12)). The exercise prescription was three sessions/week at 70-85% of peak heart rate. A two-way analysis of covariance and regression analysis was used to assess group differences and associations between pulmonary function, log transformed high-sensitivity C-reactive protein (hsCRPlog ) and white blood cell count (WBC). Following FESRT, clinically significant improvements in forced expiratory volume in 1 s (FEV1 ; 0.25 (0.08-0.43) vs. -0.06 (-0.26 to 0.15) litres) and forced vital capacity (0.22 (0.04-0.39) vs. 0.08 (-0.29 to 0.12) litres) were noted and systemic WBC (-1.45 (-2.48 to -0.50) vs. 0.41 (-0.74 to 1.56) µl) levels were suppressed compared to SOC (mean change (95% confidence interval); P < 0.05). Additionally, both ΔhsCRPlog and ΔWBC were predictors of ΔFEV1 (r2  = 0.89 and 0.43, respectively; P < 0.05). Twelve weeks of FESRT improves pulmonary function and reduces WBC in persons with sub-acute SCI. The potency of FESRT to augment pulmonary function may depend on adequate suppression of systemic inflammation.

Exercise Training Does Not Attenuate Cardiac Atrophy or Loss of Function in Individuals With Acute Spinal Cord Injury: A Pilot Study.

OBJECTIVE: To investigate the effects of 2 modes of exercise training, upper-body alone, and the addition of electrical stimulation of the lower body, to attenuate cardiac atrophy and loss of function in individuals with acute spinal cord injury (SCI). DESIGN: Randomized controlled trial. SETTING: Rehabilitation Hospital. PARTICIPANTS: Volunteers (N=27; 5 women, 22 men) who were <24 months post SCI. INTERVENTIONS: Volunteers completed either 6 months of no structured exercise (Control), arm rowing (AO), or a combination of arm rowing with electrical stimulation of lower body paralyzed muscle (functional electrical stimulation [FES] rowing). MAIN OUTCOME MEASURES: Transthoracic echocardiography was performed on each subject prior to and 6 months after the intervention. The relations between time since injury and exercise type to cardiac structure and function were assessed via 2-way repeated-measures analysis of variance and with multilevel linear regression. RESULTS: Time since injury was significantly associated with a continuous decline in cardiac structure and systolic function, specifically, a reduction in left ventricular mass (0.197 g/month; P=.049), internal diameter during systole (0.255 mm/month; P<.001), and diastole (0.217 mm/month; P=.019), as well as cardiac output (0.048 L/month, P=.019), and left ventricular percent shortening (0.256 %/month; P=.027). These associations were not differentially affected by exercise (Control vs AO vs FES, P>.05). CONCLUSIONS: These results indicate that within the subacute phase of recovery from SCI there is a linear loss of left ventricular cardiac structure and systolic function that is not attenuated by current rehabilitative aerobic exercise practices. Reductions in cardiac structure and function may increase the risk of cardiovascular disease in individuals with SCI and warrants further interventions to prevent cardiac decline.

Effect of hybrid FES exercise on body composition during the sub-acute phase of spinal cord injury.

OBJECTIVES: To determine the Effect of Hybrid functional electrically stimulated (FES) Exercise on Body Composition during the Sub-acute Phase of Spinal Cord Injury (SCI). DESIGN: Randomized Clinical Trial. SETTING: Rehabilitation Hospital. PARTICIPANTS: Patients within sub-acute phase (3-24 months) of SCI. INTERVENTIONS: We investigated if high-intensity exercise training via the addition of functional electrically stimulated (FES) leg muscles, provides sufficient stimulus to mitigate against body composition changes in the sub-acute phase after SCI. MAIN OUTCOME MEASURES: We explored potential effects of FES row training (FESRT) on body fat gain, lean mass loss, and cardiometabolic parameters and compared the effects of 6-month of FESRT (n = 18) to standard of care (SOC, n = 13). Those in SOC were crossed over to FESRT. RESULTS: FESRT resulted in greater exercise capacity and a tendency for lesser total body fat accumulation with a significant increase in total and leg lean mass (p<0.05). In addition pelvis and total bone mineral density declines were significantly less (p<0.05). Compared to SOC, FESRT did not lead to any significant difference in insulin sensitivity or serum lipids. However, HbA1C levels were significantly decreased in SOC participants who crossed over to 6-month FESRT. CONCLUSION: FESRT early after SCI provides a sufficient stimulus to mitigate against detrimental body composition changes. This may lead to prevention of losses in lean mass, including bone.

Serotonin 1A agonist and cardiopulmonary improvements with whole-body exercise in acute, high-level spinal cord injury: a retrospective analysis.

PURPOSE: High-level spinal cord injury (SCI) can result in spinal and supraspinal respiratory control deficits leading to insufficient ventilatory responses to exercise and training-related adaptations. We hypothesized a serotonin agonist, known to improve respiratory function in animal models, would improve adaptations to whole-body functional electrical stimulation (FES) exercise training in patients with acute high-level SCI. METHODS: We identified 10 patients (< 2 years of injury with SCI from C4 to T3) in our program who had performed 6 months of FES-row training while on Buspirone (29 ± 17 mg/day) between 2012 and 2018. We also identified well-matched individuals who trained for six months but not on Buspirone (n = 11). A peak incremental FES-rowing exercise test and resting pulmonary function test had been performed before and after training. RESULTS: Those on Buspirone demonstrated greater increases in peak oxygen consumption (VO2peak: + 0.24 ± 0.23 vs. + 0.10 ± 0.13 L/min, p = 0.08) and peak ventilation (VEpeak: + 6.5 ± 8.1 vs. - 0.7 ± 6.9 L/min, p < 0.05) compared to control. In addition, changes in VO2peak and VEpeak were correlated across all patients (r = 0.63, p < 0.01), but most strongly in those on Buspirone (r = 0.85, p < 0.01). Furthermore, changes in respiratory function correlated with increased peak tidal volume in the Buspirone group (r > 0.66, p < 0.05). CONCLUSION: These results suggest Buspirone improves cardiorespiratory adaptations to FES-exercise training in individuals with acute, high-level SCI. The strong association between increases in ventilatory and aerobic capacities suggests improved respiratory function is a mechanism; however, controlled studies are needed to determine if this preliminary finding is reproducible.

Cardiometabolic Effects of High-Intensity Hybrid Functional Electrical Stimulation Exercise after Spinal Cord Injury.

INTRODUCTION: The prevalence of cardiometabolic disease following spinal cord injury is known to be high. However, it is unknown whether engaging in high-intensity exercise, which is advocated by recent guidelines, is beneficial or feasible for these individuals. OBJECTIVE: To assess the effects of high-intensity, whole-body exercise on the prevalence of cardiometabolic disease in individuals with spinal cord injury. DESIGN: Combination of a randomized controlled trial and an open label intervention study of functional electrical stimulation legs plus arms rowing. SETTING: Outpatient academic rehabilitation hospital. PARTICIPANTS: Forty individuals with spinal cord injury, with American Spinal Injury Association (ASIA) impairments scales A-D and neurological levels of injury C1-T12. INTERVENTION: Six months of high-intensity, hybrid-functional electrical stimulation rowing. MAIN OUTCOME MEASURES: Change in VO2max , serum lipids, and insulin resistance, prevalence of cardiometabolic disease. RESULTS: Individuals averaged 42.1 ± 22.0 minutes of hybrid-functional electrical stimulation rowing a week over an average of 1.69 sessions per week over the 6 months of intervention. This amounted to an average of 170.9 ± 100 km rowed, at a mean heart rate of 82.7% of individualized maximum. Only one of 40 individuals met current exercise guidelines for the full 6 months. VO2max increased significantly (P < .001), yet prevalence of cardiometabolic disease did not change significantly (decrease from 22.5% to 20%, P = .70). Hemoglobin A1c did decrease significantly over this time (P = .01), although serum lipids and fasting glucose/insulin levels were unchanged. In exploratory subanalyses assessing individuals injured ≤12 months, those with more chronic injuries decreased their triglyceride-to-high-density lipoprotein (HDL) ratio (P = .04), a marker of cardiac mortality. Stratifying by neurological level of injury, individuals with paraplegia had worsened low-density lipoprotein (LDL) level (P = .02) and total cholesterol-to-HDL ratio (P = .04) over the 6-month intervention. CONCLUSIONS: Sustained high-intensity exercise with hybrid functional electrical stimulation rowing does not decrease the prevalence of cardiometabolic disease after spinal cord injury.

Gains in aerobic capacity with whole-body functional electrical stimulation row training and generalization to arms-only exercise after spinal cord injury.

STUDY DESIGN: Longitudinal study in adults (n = 27; 19-40 years old) with tetraplegic or paraplegic spinal cord injury (SCI). OBJECTIVES: Determine physiological adaptations and generalizable fitness effects of 6 months of whole-body exercise training using volitional arm and functional electrical stimulation (FES) leg rowing. SETTING: Outpatient hospital-based exercise facility and laboratory. METHODS: Participants enrolled in hybrid FES-row training (FESRT) and performed peak exercise tests with arms-only (AO; baseline and 6 months) and FES rowing (baseline, 3, 6 months). RESULTS: Participants demonstrated increased aerobic capacity (VO2peak) after FESRT (p < 0.001, np2 = 0.56) that tended to be higher when assessed with FES than AO rowing tests (0.15 ± 0.20 vs. 0.04 ± 0.22 L/min; p = 0.10). Changes in FES and AO VO2peak were significantly correlated (r = 0.55; p < 0.01), and 11 individuals demonstrated improvements (>6%) on both test formats. Younger age was the only difference between those who showed generalization of training effects and those who did not (mean age 26.6 ± 5.6 vs. 32.0 ± 5.7 years; p < 0.05) but changes in FES VO2peak correlated to time since injury in individuals <2 years post-SCI (r = -0.51, p < 0.01, n = 24). Lastly, VO2peak improvements were greater during the first 3 months vs. months 4-6 (+7.0% vs. +3.9%; p < 0.01) which suggests early training adaptations during FESRT. CONCLUSIONS: Gains in aerobic capacity after whole-body FESRT are better reflected during FES-row testing format. They relate to high-intensity exercise and appear early during training, but they may not generalize to equivalent increases in AO exercise in all individuals with SCI.

Effects of hybrid-functional electrical stimulation (FES) rowing whole-body exercise on neurologic improvement in subacute spinal cord injury: secondary outcomes analysis of a randomized controlled trial.

STUDY DESIGN: Secondary outcome measures analysis of a randomized, controlled study. OBJECTIVE: To assess the effects of hybrid-functional electrical stimulation (FES) rowing on motor and sensory recovery in individuals with spinal cord injury (SCI) 6-18 months post injury. SETTING: Outpatient rehabilitation network. METHODS: 25 participants 6-12 months after SCI were randomly assigned to hybrid-FES rowing (n = 10) or standard of care (n = 15) groups. The hybrid-FES rowing group completed 6 months of rowing scheduled 3 times per week for 26 weeks at an exercise intensity of 70-85% of maximal heart rate. The standard of care group either participated in an arm ergometer exercise program (n = 6) or a waitlist without an explicit exercise program (n = 9). Changes in motor score and combined sensory score of the International Standards for Neurological Classification of SCI (ISNCSCI) were analyzed. RESULTS: Both groups demonstrated increases in motor and combined sensory scores, but no significant differences were noted between intervention groups (motor difference mean ↑1.3 (95% CI, -1.9 to 4.4), combined sensory difference mean ↓10 (-30 to 18)). There was an average of 63% adherence to the hybrid-FES rowing protocol, with no significant correlation in changes in motor or combined sensory score in the hybrid-FES rowing group with total distance or time rowed. CONCLUSIONS: No significant effects to neurologic improvement were found with hybrid-FES rowing when compared with standard of care interventions in individuals with SCI 6-18 months post injury.

Acute Ventilatory Support During Whole-Body Hybrid Rowing in Patients With High-Level Spinal Cord Injury: A Randomized Controlled Crossover Trial.

BACKGROUND: High-level spinal cord injury (SCI) results in profound spinal and supraspinal deficits, leading to substantial ventilatory limitations during whole-body hybrid functional electrical stimulation (FES)-rowing, a form of exercise that markedly increases the active muscle mass via electrically induced leg contractions. This study tested the effect of noninvasive ventilation (NIV) on ventilatory and aerobic capacities in SCI. METHODS: This blinded, randomized crossover study enrolled 19 patients with SCI (level of injury ranging from C4 to T8). All patients were familiar with FES-rowing and had plateaued in their training-related increases in aerobic capacity. Patients performed two FES-rowing peak exercise tests with NIV or without NIV (sham). RESULTS: NIV increased exercise tidal volume (peak, 1.50 ± 0.31 L vs 1.36 ± 0.34 L; P < .05) and reduced breathing frequency (peak, 35 ± 7 beats/min vs 38 ± 6 beats/min; P < .05) compared with the sham test, leading to no change in alveolar ventilation but a trend toward increased oxygen uptake efficiency (P = .06). In those who reached peak oxygen consumption (Vo2peak) criteria (n = 13), NIV failed to significantly increase Vo2peak (1.73 ± 0.66 L/min vs 1.78 ± 0.59 L/min); however, the range of responses revealed a correlation between changes in peak alveolar ventilation and Vo2peak (r = 0.89; P < .05). Furthermore, those with higher level injuries and shorter time since injury exhibited the greatest increases in Vo2peak. CONCLUSIONS: Acute NIV can successfully improve ventilatory efficiency during FES exercise in SCI but may not improve Vo2peak in all patients. Those who benefit most seem to be patients with cervical SCI within a shorter time since injury. TRIAL REGISTRY: ClinicalTrials.gov; Nos.: NCT02865343 and NCT03267212; URL: www.clinicaltrials.gov.

Muscle Fatigue in Response to Electrical Stimulation Pattern and Frequency in Spinal Cord Injury.

BACKGROUND: Functional electrical stimulation (FES) is widely used to induce functional movements for paralyzed muscles. However, rapid muscle fatigue during FES-induced muscle contractions limits FES clinical efficacy. OBJECTIVE: To investigate muscle fatigue response across stimulation patterns and frequencies during FES in able-bodied individuals and in those with spinal cord injury (SCI). DESIGN: Four stimulation protocols combining 20 and 40 Hz average frequency with either constant frequency trains (CFTs) or with doublet frequency trains (DFTs) were applied to the quadriceps of seven adults with SCI and eight able-bodied participants. SETTING: A FES-row training laboratory. PARTICIPANTS: Seven individuals with SCI (one female; age range, 25 ± 6 years) and eight age-matched able-bodied participants (one female). INTERVENTION: None. MAIN OUTCOME MEASURES: Fatigue was defined as the number of contractions until force decreased by 20% from the target level of 25% maximal contraction force. The number of contractions and the stimulation current used during the four stimulation protocols were compared. RESULTS: There was a significant effect of frequency, as well as interaction between group and stimulation pattern (P < .05). In both groups, 20-Hz trains increased the number of contractions to fatigue compared to 40-Hz trains. However, the responses to the pattern of stimulation differed. In the able-bodied participants, CFT increased the number of contractions to fatigue compared to DFT, whereas in those with SCI, DFT increased the number of contractions to fatigue. In fact, DFT resulted in similar number of contractions to fatigue in both populations. CONCLUSIONS: These results indicate that DFT at 20 Hz may be a better stimulation protocol to delay fatigue onset in the SCI population than the other three protocols. In addition, this work implies that results from able-bodied persons may not be directly applicable to those with SCI.

Augmenting exercise capacity with noninvasive ventilation in high-level spinal cord injury.

High-level spinal cord injury (SCI) results in a very limited innervated skeletal muscle mass that strongly reduces exercise capacity. Our recent work showed that when adding functional electrical stimulation (FES) of the paralyzed legs (hybrid FES-exercise) to produce higher exercise capacity, peak ventilation became a limiting factor to training-induced improvement in aerobic capacity. Our assumption was that the systemic adaptations to exercise training are delimited by the maximal ventilation that can be achieved. However, herein, we present a case showing an acute increase in aerobic capacity when using noninvasive ventilatory support (NIV) during FES-rowing test in an individual who had previously experimented a plateau in his aerobic capacity for 18 mo. An 18-yr-old man with C5 SCI trained with arms-only rowing for 6 mo and subsequently trained with hybrid FES-rowing for 18 mo. Peak minute ventilation (V̇epeak) and peak oxygen consumption (V̇o2peak) were increased after arms-only training and increased further with 6 mo of hybrid FES-row training. Despite continued intense and frequent, hybrid FES-row training, neither V̇epeak nor V̇o2peak increased further over the next year (1.94 and 66.0 l/min). However, when this individual performed a FES-rowing V̇o2peak test with the addition of NIV, V̇epeak increased by 5 l/min, resulting in an improved V̇o2peak (2.23 l/min, +12%). This case demonstrates that noninvasive ventilation can overcome limitations to ventilation in high-level SCI and improve aerobic capacity during hybrid FES-exercise to a level not otherwise achievable. In addition, it broadly illustrates the intimate role of pulmonary function in determining the capacity to perform exercise.

Relationship of Spinal Cord Injury Level and Duration to Peak Aerobic Capacity With Arms-Only and Hybrid Functional Electrical Stimulation Rowing.

OBJECTIVE: The aim of the study was to assess the relationship of spinal cord injury level and duration to peak aerobic capacities during arms-only rowing compared with hybrid Functional Electrical Stimulation (FES)-rowing. DESIGN: Comparison of peak aerobic capacity (VO2), peak ventilation, peak respiratory exchange ratio, and peak heart rate were measured during arms-only rowing and FES-rowing obtained from graded exercise tests. RESULTS: Peak aerobic values were strongly related to injury level and injury duration for both arms-only rowing (r = 0.67, P < 0.05) and FES-rowing (r = 0.61, P < 0.05). Peak aerobic capacities were greater across all injury levels and durations with FES-rowing compared with arms-only rowing. Differences in VO2 were inversely related to injury level (r = 0.55, P < 0.05) with greater increases in VO2 in higher level injuries. Injury durations of less than 2 yrs had greater percent increases in VO2 with FES-rowing. CONCLUSIONS: FES-rowing acutely post injury may have the greatest effect to maintain function and improve VO2. This impact seems to be greatest in those with higher level injuries.

Slow Yogic Breathing and Long-Term Cardiac Autonomic Adaptations: A Pilot Study.

OBJECTIVES: To examine whether long-term practice of yogic breathing alters cardiac autonomic control. DESIGN: Age-sex matched, cross-sectional, physiologic pilot study. SETTINGS/LOCATION: Spaulding Rehabilitation Hospital, Cardiovascular Laboratory, Cambridge, MA. PARTICIPANTS: Twenty-six (26) long-term yoga practitioners and 26 age- and sex-matched controls, free of cardiovascular disease. OUTCOME: Cardiac vagal outflow as assessed by respiratory sinus arrhythmia (RSA). RESULTS: During unpaced (spontaneous) breathing, yoga practitioners exhibited augmented RSA compared to controls (yoga 364.8 ± 75.3 vs. 194.7 ± 46.0 ms2Hz-1, p = 0.03). However, during paced breathing at 0.25 Hz (15 breaths/min), which accounts for inter- and intravariability in breath rate, RSA did not differ between groups (yoga 224.8 ± 48.4 vs. 271.3 ± 59.7 ms2Hz-1, p = 0.98). Furthermore, the relationship between age and RSA, such that RSA declines with age, did not qualitatively differ between groups. CONCLUSIONS: Long-term practice of yogic slow breathing does not appear to augment cardiac vagal control nor prevent known age-related declines.

Assessing kinematics and kinetics of functional electrical stimulation rowing.

Hybrid functional electrical stimulation (FES) rowing has positive effects on cardiovascular fitness, producing significantly greater aerobic power than either upper body or FES exercise alone. However, there is minimal information on the kinematics, kinetics, and mechanical efficiency of FES-rowing in the spinal cord injured (SCI) population. This study examined the biomechanics of FES-rowing to determine how motions, forces, and aerobic demand change with increasing intensity. Six individuals with SCI and six able-bodied subjects performed a progressive aerobic capacity rowing test. Differences in kinematics (motion profiles), kinetics (forces produced by the feet and arms), external mechanical work, and mechanical efficiency (work produced/volume of oxygen consumed) were compared in able-bodied rowing vs. SCI FES-rowing at three comparable subpeak workloads. With increasing exercise intensity (measured as wattage), able-bodied rowing increased stroke rate by decreasing recovery time, while FES-rowing maintained a constant stroke rate, with no change in drive or recovery times. While able-bodied rowers increased leg and arm forces with increasing intensity, FES-rowers used only their arms to achieve a higher intensity with a constant and relatively low contribution of the legs. Oxygen consumption increased in both groups, but more so in able-bodied rowers, resulting in able-bodied rowers having twice the mechanical efficiency of FES-rowers. Our results suggest that despite its ability to allow for whole body exercise, the total force output achievable with FES-rowing results in only modest loading of the legs that affects overall rowing performance and that may limit forces applied to bone.

Hybrid functional electrical stimulation exercise training alters the relationship between spinal cord injury level and aerobic capacity.

OBJECTIVE: To test the hypothesis that hybrid functional electrical stimulation (FES) row training would improve aerobic capacity but that it would remain strongly linked to level of spinal cord lesion because of limited maximal ventilation. DESIGN: Longitudinal before-after trial of 6 months of FES row training. SETTING: Exercise for persons with disabilities program in a hospitaL. PARTICIPANTS: Volunteers (N=14; age range, 21-63y) with complete spinal cord injury (SCI) (T3-11) who are >2 years postinjury. INTERVENTION: Six months of FES row training preceded by a variable period of FES strength training. MAIN OUTCOME MEASURES: Peak aerobic capacity and peak exercise ventilation before and after 6 months of FES row training. RESULTS: FES row training significantly increased peak aerobic capacity and peak minute ventilation (both P<.05). Prior to FES row training, there was a close relation between level of SCI and peak aerobic capacity (adjusted R(2)=.40, P=.009) that was markedly reduced after FES row training (adjusted R(2)=.15, P=.10). In contrast, the relation between level of injury and peak minute ventilation was comparable before and after FES row training (adjusted R(2)=.38 vs .32, both P<.05). CONCLUSIONS: The increased aerobic capacity reflects more than increased ventilation; FES row training effectively circumvents the effect of SCI on peak aerobic capacity by engaging more muscle mass for training, independent of the level of injury.

Aerobic capacity with hybrid FES rowing in spinal cord injury: comparison with arms-only exercise and preliminary findings with regular training.

OBJECTIVE: To determine the magnitude and range of increases in peak aerobic capacity with hybrid-functional electrical stimulation (FES) rowing versus arms-only rowing in persons with spinal cord injury. DESIGN: Comparison of graded exercise tests for peak responses during FES rowing and arms-only rowing. Preliminary data on adaptations to FES row training were gathered in a subset of individuals. SETTING: Outpatient cardiovascular research laboratory. PARTICIPANTS: Six male patients with spinal cord injury (T4-T9, American Spinal Injury Association class A). METHODS OR INTERVENTION: Arms-only rowing was compared with FES rowing, in which the person who is exercising synchronizes the voluntarily controlled upper body movement with the FES-controlled leg movement via stimulation to the paralyzed leg muscles. A subgroup (n = 3) completed at least 6 months of a progressive FES row training exercise program with graded exercise tests every 6 months. MAIN OUTCOME MEASUREMENTS: Peak oxygen consumption, peak ventilation, peak respiratory exchange ratio, peak heart rate, and peak oxygen pulse. RESULTS: Peak oxygen consumption was greater during FES rowing than during arms-only rowing (20.0 ± 1.9 mL/kg/min versus 15.7 ± 1.5 mL/kg/min, P = .01). Peak ventilation was similar, whereas peak respiratory exchange ratio and peak heart rate tended to be lower (P = .14 and P = .19, respectively). As a result, oxygen pulse was greater by 35% during FES rowing. Two of the three persons who completed at least 6 months of FES row training demonstrated increases in aerobic capacity greater than those previously observed in able-bodied individuals. CONCLUSIONS: FES rowing may provide a more robust exercise stimulus for persons with spinal cord injury than most options currently available because of the greater aerobic demand.