Locomotor training with incremental changes in velocity: Muscle and metabolic responses

Objective: The purpose of this study was to simultaneously measure metabolic function and EMG activation of the lower legs during incremental changes in treadmill velocity during one session of locomotor training using body weight support (BWS). Method: All of the 8 participants with a spinal cord injury (SCI; 5 individuals with tetraplegia and 3 individuals with paraplegia) were 100% wheelchair reliant. The initial treadmill velocity was 1.0 mph (0.447 m/s); after every 15 strides, the treadmill velocity was increased by 0.1 mph (0.045 m/s). Results: With incremental increases in treadmill velocity, for the individuals with tetraplegia there was a significant increase in VO₂ (p ≤ .05), VE (p ≤ .05), and left rectus femoris mean amplitude (p ≤ .05). Conclusions: Our preliminary results suggest that incremental increases in treadmill velocity impart increases in neural activation, muscle activation, and metabolic responses for individuals with motor complete and incomplete, nonambulatory SCI. Further this "one time" testing session suggests that passive-assisted locomotor training increases metabolic demand, and thus work performed, by peripheral muscle activation despite muscle paralysis.