Oral creatine supplementation enhances upper extremity work capacity in persons with cervical-level spinal cord injury

Objective: To examine the effects of short-term creatine monohydrate supplementation on the upper extremity work capacity of persons with cervical-level spinal cord injury (SCI). Design: Randomized, double-blind, placebo-controlled, crossover design study. Consists of 2 treatment phases lasting for 7 days, separated by a 21-day washout period. Setting: University research laboratory trial. Participants: Sixteen men with complete cervical-level SCI (C5-7). Intervention: Subjects were randomly assigned to I of 2 groups and received either 20g/d of creatine monohydrate supplement powder or placebo maltodextrin powder for the first treatment phase; the treatment was reversed in the second phase. Incremental peak arm ergometry tests, using 2-minute work stages and 1-minute recovery periods, were performed immediately before and after each treatment phase (total of 4 assessments). The initial stage was performed unloaded, with power output progressively increased 10 watts/stage until subjects had achieved volitional exhaustion. Main Outcome Measures: Peak power output, time to fatigue, heart rate, and metabolic measurements, including oxygen uptake (Vo₂), minute ventilation, tidal volume (V_T), and respiration frequency. Results: Significantly greater values of Vo₂, Vco₂ and V_T at peak effort after creatine supplementation (P < .001). Conclusions: Creatine supplementation enhances the exercise capacity in persons with complete cervical-level SCI and may promote greater exercise training benefits.