Effects of creatine and sodium bicarbonate co-ingestion on multiple indices of mechanical power output during repeated wingate tests in trained men

This study investigated the effects of creatine and sodium bicarbonate co-ingestion on mechanical power during repeated sprints. Nine well-trained men (age = 21.6 ± 0.9 yr, stature = 1.82 ± 0.05 m, body mass = 80.1 ± 12.8 kg) participated in a double-blind, placebo-controlled, counterbalanced, crossover study using six 10-s repeated Wingate tests. Participants ingested either a placebo (0.5 g·kg-1 of maltodextrin), 20 g·d-1 of creatine monohydrate + placebo, 0.3 g·kg-1 of sodium bicarbonate + placebo, or co-ingestion + placebo for 7 d, with a 7 d washout between conditions. Participants were randomised into two groups with a differential counterbalanced order. Creatine conditions were ordered first and last. Indices of mechanical power output (W), total work (J) and fatigue index (W·s-1) were measured during each test and analysed using the magnitude of differences between groups in relation to the smallest worthwhile change in performance. Compared to placebo, both creatine (effect size (ES) = 0.37-0.83) and sodium bicarbonate (ES = 0.22-0.46) reported meaningful improvements on indices of mechanical power output. Co-ingestion provided small meaningful improvements on indices of mechanical power output (W) compared to sodium bicarbonate (ES = 0.28-0.41), but not when compared to creatine (ES = -0.21-0.14). Co-ingestion provided a small meaningful improvement in total work (J) (ES = 0.24) compared to creatine. Fatigue index (W·s-1) was impaired in all conditions compared to placebo. In conclusion, there was no meaningful additive effect of creatine and sodium bicarbonate co-ingestion on mechanical power during repeated sprints.