Creatine supplementation for weak muscles in persons with chronic tetraplegia: a randomized double-blind placebo-controlled crossover trial.

BACKGROUND AND OBJECTIVES:Creatine supplementation improves muscle strength in some patient populations with neurologic disorders. The purpose of this study was to determine whether creatine supplementation improves muscle strength and endurance in weak upper limb muscles in persons with tetraplegia, and whether it improves function. METHODS:Outpatients with tetraplegia and mild wrist extensor weakness were randomized to receive either creatine or placebo in a double-blind crossover design. During creatine supplementation, participants were loaded with 10 g orally twice per day for 6 days, then maintained on 5 g daily until undergoing testing. Main outcome measures, performed at baseline, after placebo, and after creatine supplementation, included maximal voluntary wrist extensor isometric contraction strength (MVC), endurance times for 5 submaximal wrist extensor contractions, and the Grasp and Release Test for hand function. RESULTS:Eight individuals (7 men, 1 woman) with tetraplegia met inclusion criteria and completed all study phases. The mean age of participants was 48 years, and 7 of 8 had C6 motor level injuries. There were no significant differences in MVC, endurance times, or hand function for creatine vs placebo. CONCLUSION:Creatine does not improve MVC and endurance of weak wrist extensors and does not improve hand function in individuals with tetraplegia.