Table 1. Mean oxygen uptake for subjective placebo responders (n = 3) and percentage difference from mean oxygen uptake for placebo non-responders (n = 9) in informed caffeine/received caffeine and informed caffeine/received placebo conditions. Condition Oxygen uptake l·min-1 Difference (%) from placebo non-responders Chances effect is clinically beneficial (trivial/harmful)+ Mean (SD) Mean (SD) 95% CI* Informed caffeine/received caffeine 3.5 (0.4) 7.0 (10.9) -2.6 to 16.7 4 (8/89) Informed caffeine/received placebo 3.6 (0.1) 6.0 (11.6) -3.9 to 15.9 6 (11/83) smallest worthwhile effect of 1.5%. 95% CI = 95% confidence interval.