Table 1. Mean (±SD) performance times (s) in a 6 x 75 m maximal freestyle sprint protocol after supplementation of placebo or caffeine in national level swimmers (n = 9).
SprintNumber Placebo Caffeine * Effect Size(d)
1 40.24 (1.22) 39.88 (.74) .36
2 40.30 (1.16) 39.94 (1.18) .31
3 40.70 (1.00) 39.70 (.96) 1.02 §
4 40.98 (1.02) 40.14 (.98) .84 §
5 40.68 (1.26) 40.20 (1.42) .36
6 40.60 (1.30) 40.48 (1.70) .09
Mean 40.58 (1.08) 40.06 (1.02) 050 #
* Denotes significant treatment effect (α=0.05).
§ Denotes large effect (d >0.80).
# Denotes moderate effect (d >0.50).