The effects of acute ingestion of caffeine on short-duration high-intensity performance are equivocal, while studies of novel modes of delivery and the efficacy of low doses of caffeine are warranted. The aims of the present study were to investigate the effect of acute ingestion of caffeinated chewing gum on repeated sprint performance (RSP) in team sport athletes, and whether habitual caffeine consumption alters the ergogenic effect, if any, on RSP. A total of 18 male team sport athletes undertook four RSP trials using a 40-m maximum shuttle run test, which incorporates 10 × 40-m sprints with 30 s between the start of each sprint. Each participant completed two familiarization sessions, followed by caffeine (CAF; caffeinated chewing gum; 200 mg caffeine) and placebo (PLA; noncaffeinated chewing gum) trials in a randomized, double-blind manner. RSP, assessed by sprint performance decrement (%), did not differ (p = .209; effect size = 0.16; N = 18) between CAF (5.00 ± 2.84%) and PLA (5.43 ± 2.68%). Secondary analysis revealed that low habitual caffeine consumers (<40 mg/day, n = 10) experienced an attenuation of sprint performance decrement during CAF relative to PLA (5.53 ± 3.12% vs. 6.53 ± 2.91%, respectively; p = .049; effect size =0.33); an effect not observed in moderate/high habitual caffeine consumers (>130 mg/day, n = 6; 3.98 ± 2.57% vs. 3.80 ± 1.79%, respectively; p = .684; effect size = 0.08). The data suggest that a low dose of caffeine in the form of caffeinated chewing gum attenuates the sprint performance decrement during RSP by team sport athletes with low, but not moderate-to-high, habitual consumption of caffeine.
Mark Evans, Peter Tierney, Nicola Gray, Greg Hawe, Maria Macken and Brendan Egan
Mark Eys, M. Blair Evans, Luc J. Martin, Jeannine Ohlert, Svenja A. Wolf, Michael Van Bussel and Charlotte Steins
A previous meta-analysis examining the relationship between cohesion and performance (Carron, Colman, Wheeler, & Stevens, 2002) revealed that this relationship was significantly stronger for female teams as compared with male teams. The purpose of the current study was to explore perceptions of the cohesion-performance relationship by coaches who have led teams of both genders. Semistructured interviews were employed with Canadian and German coaches with previous experience leading both male and female sport teams. The information obtained through the interviews yielded a number of categories pertaining to potential similarities and differences within female and male sport teams including: (a) the nature of cohesion (e.g., direction of the cohesion-performance relationship), (b) antecedents of cohesion (e.g., approaches to conflict), and (c) the management of cohesion (e.g., developing social cohesion). Overall, the results offer testable propositions regarding gender differences and group involvement in a sport context as well as informing best practices such that teams can attain optimal performance.