Contractile properties, fatigue and recovery are not influenced by short-term creatine supplementation in human muscle

There have been several studies on the effect of short-term creatine (Cr) s upplementation on exercise performance, but none have investigated both vol untary and stimulated muscle contractions in the same experiment. Fourteen moderately active young men (19-28 years) were randomly assigned, in a doub le blind manner, to either a creatine (Cr) or placebo (P) group. The subjec ts supplemented their regular diet 4 times a day for 5 days with either 5 g Cr + 5 g maltodextrin (Cr group), or 5 g maltodextrin (P group). Isometric maximal voluntary contraction (MVC), muscle activation. as assessed using the modified twitch interpolation technique, electrically stimulated contra ctile properties, electromyography (EMG), endurance time and recovery from fatigue were measured in the elbow flexors. The fatigue protocol involved b oth voluntary and stimulated contractions. Following supplementation there was a significant weight gain in the Cr group (1.0 kg), whereas the P group did not change. For each group, pre-supplementation measures mere not sign ificantly different from post-supplementation for MVC, twitch and tetanic t ensions at rest, time to peak tension, half-relaxation time and contraction duration. Prior to Cr supplementation time to fatigue was similar to 10 +/ - 4 min (mean +/- S.E.M,) for both groups, and following supplementation th ere was a non-significant increase of similar to 1 min in each group. MVC f orce, muscle activation, EMC, stimulated tensions and durations were simila r for the Cr and P groups over the course of the fatigue protocol and did n ot change after supplementation. Furthermore, recovery of MVC, stimulated t ensions and contractile speeds did not differ as a result of Cr supplementa tion. These results indicate that short term Cr supplementation does not in fluence isometric elbow flexion force, muscle activation, stimulated contra ctile properties, or delay time to fatigue or improve recovery.