Acute effects of caffeine supplementation on taekwondo performance: the influence of competition level and sex. - Ouergui, Ibrahim; Delleli, Slaheddine; Bridge, Craig Alan; Messaoudi, Hamdi; Chtourou, Hamdi; Ballmann, Christopher Garrett; Ardigò, Luca Paolo; Franchini, Emerson (Scientific Reports, 2023)