Effect of creatine supplementation on muscle capacity in individuals with multiple sclerosis

There has been interest in the use of exogenous creatine (Cr) as an adjunct treatment for neurological disorders. Creatine enhances bouts of activity through augmenting phosphocreatine for increased synthesis of ATP; however, multiple sclerosis (MS) individuals suffering from muscle weakness have not been shown to improve muscle work after 5 days of Cr supplementation. This study's purpose was to determine whether the extended duration would increase muscle capacity. In a double-blind, crossover trial, with a 3-week washout period, eleven MS subjects were randomly assigned to either Cr (5 g 4/day, day 1-7: 2.5 g 2/day, day 8-14) or placebo groups for two 14-day periods. Biodex Dynamometer recorded total work and power over three bouts of 30 maximal knee extensions and flexions. Total work was nonsignificant with Cr for knee extension (pretest 1277.7 ± 214.9 J vs. posttest = 1313.14 ± 200.5 J; p = 0.81) and flexion (pretest = 1220.7 ± 200.5 J vs. posttest = 1302.10 J ± 189.64 J; p = 0.93). Creatine did not enhance muscle power in knee extension (p = 0.31; pretest = 82.1 ± 12.7 W vs. posttest = 87.7 ± 12.6 W) or flexion (p = 0.29; pretest = 75.3 ± 12.1 W vs. posttest = 81.2 ± 11.1 W). Therefore, 14 days of Cr supplementation did not improve muscle capacity or habitual fatigue in MS individuals.