Intra-individual variability – inconsistency
For SRT and CRT IIV-I, there was no significant main effect between supplements or supplement × time interaction (A significant time effect was detected in SRT (A significant time effect was also detected in CRT (
Intraindividual variability inconsistency for both choice (CRT) and simple reaction time (SRT) cognitive tests
Therefore, SRT IIV-I increased significantly after exercise with placebo but not under supplementation with caffeine or guarana, and CRT IIV-I decreased significantly after exercise with guarana only.