Effect of caffeine supplementation on repeated sprint running performance.
AIM: This study examined the effects of 6 mgxkg(-1) caffeine ingestion in team-sport players (N.=10) on repeated-sprint running performance (5 sets of 6 x 20 m) and reaction times, 60 min after caffeine or placebo ingestion. METHODS: Best single sprint and total set sprint times, blood lactate and simple and choice reaction times (RT) were measured. RESULTS: Total sprint times across sets 1, 3 and 5 (departure every 25 s) were significantly faster after caffeine (85.49+/-5.55 s) than placebo (86.98+/-5.78 s) (P<0.05). Similarly, total sprint times across sets 2 and 4 (departure every 60 s), were significantly faster after caffeine (55.99+/-3.64 s) than placebo (56.77+/-3.74 s) (P<0.05). Significantly higher blood lactates were recorded in caffeine compared to placebo after set 3 (13.1+/-1.2 vs 10.3+/-1.4 mmolxL(-1)) (P<0.05) and set 5 (13.1+/-1.3 vs 10.3+/-1.6 mmolxL(-1)) (P<0.01). There were no significant effects on simple or choice RT, although effect sizes suggested improved post-exercise times after caffeine. CONCLUSION: Caffeine ingestion 60 min prior to exercise can enhance repeated sprint running performance and is not detrimental to reaction times.