Shortening of muscle relaxation time after creatine loading

The effect of creatine (Cr) supplementation on muscle isometric torque gene ration and relaxation was investigated in healthy male volunteers. Maximal torque (Tmax), contraction time (CT) from 0.25 to 0.75 of Tmax, and relaxat ion time (RT) from 0.75 to 0.25 of Tmax were measured during 12 maximal iso metric 3-s elbow flexions interspersed by 10-s rest intervals. Between the pretest and the posttest, subjects ingested Cr monohydrate (4 x 5 g/day; n = 8)or placebo (n = 8) for 5 days. Pretest Tmax, CT, and RT were similar in Cr and placebo groups. Also in the posttest, Tmax and CT were similar betw een groups. However, posttest RT was decreased consistently by similar to 2 0% (P < 0.05) in the Cr group from the first to the last of the 12 contract ions. In addition, the mean decrease in RT after Cr loading was positively correlated with pretest RT (r = 0.82). It is concluded that Cr loading faci litates the rate of muscle relaxation during brief isometric muscle contrac tions without affecting torque production.