Creatine-electrolyte supplementation improves repeated sprint cycling performance: A double blind randomized control study.

BACKGROUND: Creatine supplementation is recommended as an ergogenic aid to improve repeated sprint cycling performance. Furthermore, creatine uptake is increased in the presence of electrolytes. Prior research examining the effect of a creatine-electrolyte (CE) supplement on repeated sprint cycling performance, however, did not show post-supplementation improvement. The purpose of this double blind randomized control study was to investigate the effect of a six-week CE supplementation intervention on overall and repeated peak and mean power output during repeated cycling sprints with recovery periods of 2 min between sprints. METHODS: Peak and mean power generated by 23 male recreational cyclists (CE group: n = 12; 24.0 ± 4.2 years; placebo (P) group: n = 11; 23.3 ± 3.1 years) were measured on a Velotron ergometer as they completed five 15-s cycling sprints, with 2 min of recovery between sprints, pre- and post-supplementation. Mixed-model ANOVAs were used for statistical analyses. RESULTS: A supplement-time interaction showed a 4% increase in overall peak power (pre: 734 ± 75 W; post: 765 ± 71 W; p = 0.040; ηp2 = 0.187) and a 5% increase in overall mean power (pre: 586 ± 72 W; post: 615 ± 74 W; p = 0.019; ηp2 = 0.234) from pre- to post-supplementation for the CE group. For the P group, no differences were observed in overall peak (pre: 768 ± 95 W; post: 772 ± 108 W; p = 0.735) and overall mean power (pre: 638 ± 77 W; post: 643 ± 92 W; p = 0.435) from pre- to post-testing. For repeated sprint analysis, peak (pre: 737 ± 88 W; post: 767 ± 92 W; p = 0.002; ηp2 = 0.380) and mean (pre: 650 ± 92 W; post: 694 ± 87 W; p < 0.001; ηp2 = 0.578) power output were significantly increased only in the first sprint effort in CE group from pre- to post-supplementation testing. For the P group, no differences were observed for repeated sprint performance. CONCLUSION: A CE supplement improves overall and repeated short duration sprint cycling performance when sprints are interspersed with adequate recovery periods.

Individuals With Knee Osteoarthritis Demonstrate Interlimb Asymmetry in Pedaling Power During Stationary Cycling.

Cycling is commonly prescribed for physical rehabilitation of individuals with knee osteoarthritis (OA). Despite the known therapeutic benefits, no research has examined interlimb symmetry of power output during cycling in these individuals. We investigated the effects of external workload and cadence on interlimb symmetry of crank power output in individuals with knee OA versus healthy controls. A total of 12 older participants with knee OA and 12 healthy sex- and age-matched controls were recruited. Participants performed 2-minute bouts of stationary cycling at 4 workload-cadence conditions (75 W at 60 rpm, 75 W at 90 rpm, 100 W at 60 rpm, and 100 W at 90 rpm). Power output contribution of each limb toward total crank power output was computed over 60 crank cycles from the effective component of pedal force, which was perpendicular to the crank arm. Across the workload-cadence conditions, the knee OA group generated significantly higher power output with the severely affected leg compared with the less affected leg (10% difference; P = .02). Healthy controls did not show interlimb asymmetry in power output (0.1% difference; P > .99). For both groups, interlimb asymmetry was unaffected by external workload and cadence. Our results indicate that individuals with knee OA demonstrate interlimb asymmetry in crank power output during stationary cycling.