Fig. 2

Means and SD of countermovement jump height with caffeine (solid bars) and placebo (hatched bars). Participants were divided according to cardiorespiratory (a) or neuromuscular fitness (b), with high groups shown in black and medium groups shown in grey. One to 5 correspond to time points as follows: 1, before the start of the trial; 2, between the 1st and 2nd periods; 3, immediately after the end of the 2nd period; 4, immediately before the start of the 3rd period; 5: between the 3rd and 4th periods. There were significant treatment and time effects in both a and b, as well as a significant group effect (by design) in b (p < 0.05)