Metabolic Responses to 4 Different Body Weight-Supported Locomotor Training Approaches in Persons With Incomplete Spinal Cord Injury

Objective: To describe metabolic responses accompanying 4 different locomotor training (LT) approaches. Design: Single-blind, randomized controlled trial. Setting: Rehabilitation research laboratory, academic medical center. Participants: Individuals (N = 62) with minimal walking function due to chronic motor-incomplete spinal cord injury. Intervention: Participants trained 5 days/week for 12 weeks. Groups were treadmill-based LT with manual assistance (TM), transcutaneous electrical stimulation (TS), and a driven gait orthosis (DGO) and overground (OG) LT with electrical stimulation. Main Outcome Measures: Oxygen uptake (V-O2), walking velocity and economy, and substrate utilization during subject-selected slow, moderate, and maximal walking speeds. Results: V-O2 did not increase from pretraining to posttraining for DGO (.00 +/- 18L/min, P = .923). Increases in the other groups depended on walking speed, ranging from .01 +/-.18m/s (P = .860) for TM (slow speed) to .20 +/-.29m/s (P = .017) for TS (maximal speed). All groups increased velocity but to varying degrees (DGO, .01 +/-.18Ln[m/s], P = .829; TM, .07 +/-.29Ln[m/s], P = .371; TS, .33 +/-.45Ln[m/s], P = .013; OG, .52 +/-.61Ln[m/s], P = .007). Changes in walking economy were marginal for DGO and TM (.01 +/-.20Ln[L/m], P = .926, and .00 +/-.42Ln [L/m], P = .981) but significant for TS and OG (.26 +/-.33Ln[L/m], P = .014, and .44 +/-.62Ln[L/m], P = .025). Many participants reached respiratory exchange ratios >= 1 at any speed, rendering it impossible to statistically discern differences in substrate utilization. However, after training, fewer participants reached this ceiling for each speed (slow: 9 vs 6, n = 32; moderate: 12 vs 8, n = 29; and maximal 15 vs 13, n = 28). Conclusions: DGO and TM walking training was less effective in increasing V-O2 and velocity across participant-selected walking speeds, while TS and OG training was more effective in improving these parameters and also walking economy. Therefore, the latter 2 approaches hold greater promise for improving clinically relevant outcomes such as enhanced endurance, functionality, or in-home/community ambulation. (c) 2013 by the American Congress of Rehabilitation Medicine