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Objectives: (1) To determine if a hybrid exercise (leg plus arm) training program performed immediately after functional electrical stimulation (FES) leg cycle exercise (LCE) training would further improve aerobic capacity when compared with FES leg cycle training alone, and (2) to compare the submaximal responses occurring during both FES-LCE alone and hybrid exercise in the same SCI subjects., Design: Nonrandomized control trial whereby subjects act as their own control., Setting: Outpatient rehabilitation in a primary care hospital., Patients: A volunteer sample (n = 11) of men 20 to 50 years old with complete spinal cord injury, free from cardiovascular and metabolic disease with spasticity., Interventions: Three phases of exercise training: phase I, progressive FES-LCE to 30 minutes of exercise (n = 11); phase II, 35.2 +/- 16.2 sessions of FES-LCE (n = 11); phase III, 41.4 +/- 17.7 30-minute sessions of hybrid exercise (n = 8)., Main Outcome Measures: (1) Aerobic capacity-a further increase after hybrid exercise when compared with FES-LCE alone; (2) submaximal physiologic parameters (oxygen uptake [VO2], heart rate [HR], blood lactate [BLa-])-measurement of these during constant work rate exercise and a training effect., Results: VO2 (the body's ability to utilize oxygen) significantly improved (p < .05) after both FES-LCE and then further after hybrid training. Hybrid exercise training resulted in significantly (p < .05) greater work rates and VO2 values than both FES-LCE at baseline and training work rates., Conclusion: These subjects demonstrated that hybrid exercise performed twice a week provided sufficient intensity to improve aerobic capacity and provide a medium whereby patients with SCI can burn more calories than via FES-LCE alone. This has important implications for improving the health and fitness levels of individuals with SCI and may ultimately reduce their risk of cardiovascular disease.

Eight males with spinal cord injury (SCI) participated in an exercise training program using neuromuscular electrical stimulation (NMES) leg cycle ergometry. Each subject completed a minimum of 24 (mean +/- SD = 38.1 +/- 17.2) 30-minute training sessions over a 19-week period. The initial work rate (WR) of 0 watts (W) of unloaded cycling was increased when appropriate with subjects exercising at 11.4 +/- 3.7 W (range = 6.1 W-18.3 W) at the end of the training program. Randomized block repeated measures ANOVA was used to compare pretraining and posttraining peak physiologic responses during graded NMES leg cycle tests and subpeak physiologic responses during 10 minutes of NMES leg cycle exercise at an absolute WR (0 W). A significant (P < or = 0.05) increase was observed for peak VO2; (+10%, 1.29 +/- 0.30 to 1.42 +/- 0.39 1.min-1). No other statistically significant differences were noted for any other peak variable (VCO2, VO2 ml.kg-1 min-1, VE, WR, HR, RER) pre- to posttraining. During submaximal NMES leg cycle testing, a significant decrease was noted for RER (-9.2%, 1.19 +/- 0.14 to 1.08 +/- 0.09). No other submaximal variable (VO2 1.min-1, ml.kg-1.min-1, VCO2, HR, VE) showed significant changes as a result of the training. Although the improvement in peak VO2 was not as dramatic as those reported in previous studies, it appears that NMES leg cycle training performed two times per week can significantly enhance cardiorespiratory fitness.

We examined the kinetics of VO2, VCO2, and VE following the onset of unloaded leg cycling, and in recovery, in six patients with spinal cord injury (SCI). Exercise was produced by functional electrical stimulation (FES) of the quadriceps, hamstrings, and gluteal muscles. End-exercise VO2 (1.03 +/- 0.16 l.min-1), VCO2 (1.20 +/- 0.22 l.min-1) and VE (41 +/- 10 l.min-1) were elevated compared to values typically seen in healthy ambulatory subjects performing similar unloaded cycling. Mean response times for the on transients (MRTon) were both long and variable across subjects for VO2 (165 +/- 62 s), VCO2 (173 +/- 58 s), and VE (202 +/- 61 s). Recovery kinetics showed much less intersubject variability, and for five of six subjects were faster than the equivalent exercise MRT for all three variables (MRToff for VO2 of 103 +/- 28 s, VCO2 136 +/- 20 s, and VE 144 +/- 34 s), but P > 0.05 for all three. Size of the O2 deficit (1.96 +/- 0.90 l) and end-exercise lactate (7.05 +/- 1.65 mmol.l-1) were similar to values reported for healthy sedentary subjects performing maximal voluntary exercise, but the end-exercise heart rate (102 +/- 16 bpm) was lower than expected for this intensity of exercise. In conclusion, FES-induced unloaded cycling leads to exaggerated responses of pulmonary gas exchange and long time constants in patients with SCI. The delayed kinetics may be due in part to a blunted increase in heart rate in addition to severe deconditioning.