Ingestion of creatine monohydrate immediately prior to exercise does not increase performance in creatine loaded individuals

Abstract

Twenty‐four participants (15 men; 9 women) performed baseline testing (day 1) after following a standard unsupplemented diet. This was followed by the daily ingestion of a creatine formulation dietary loading sequence for 5 days (days 2–6, Phosphagen HP™ 5.25 g creatine mono‐hydrate (CR) 4‐ 33 g dextrose). Loading consisted of 4 servings of Phosphagen HP™ per day. On day 7, participants were randomly assigned to one of three double‐blind treatments administered 1 h before testing. During treatment, subjects were randomly fed: (a) 10 g of CR, (b) 80 g of dextrose, or (c) 10 g of CR + 80 g of dextrose. Variables evaluating the effectiveness of the different regimens included body mass, two 30‐s Wingate anaerobic performance power tests and measurement of serum creatine concentration 65 and 5 min before each trial. Plasma ammonia concentration was also measured 65 min before and 5 min after each trial. The results of this trial show a significant non‐placebo controlled effect for the pooled, group and gender data (P ≤ 0.05). Following 5 days of Phosphagen HP™ loading, significant pooled group mean changes were: (1) body mass (+1.08 kg), (2) anaerobic power (1st Wingate = + 1.28 kJ; 2nd Wingate 2 = (+1.92kJ), (3) serum creatine concentration 65 min prior to testing trials (+624.06 μmol · L−1) and (4) post‐test plasma ammonia concentration (—83.63 μmol · L−1). However, on day 7, in placebo group condition, no between group performance effects were noted following an acute 10 g oral bolus of CR 1 h prior to the exercise test. It is concluded that no performance benefit is due to acute ingestion of CR 1 h before exercise in CR loaded individuals.