The effect of caffeine on exercise performance is not influenced by ADORA2A genotypes, alone or pooled with CYP1A2 genotypes, in adolescent athletes

Purpose This study investigated the influence of the different genotypes of ADORA2A (1976 C > T, rs 5751876), alone or pooled with CYP1A2 (163 C > A rs 762551) genotypes, on the ergogenic effects of caffeine (CAF) on various aspects of physical performance in male adolescent athletes. Methods Ninety male adolescent athletes (age = 15.5 +/- 2 years) were classified according to their genotypes for 1976 C > T ADORA2A (TT homozygous or C-ADORA2A allele carriers) and 163 C > A CYP1A2 (AA homozygous or C-CYP1A2 allele carriers). Participants were further divided in four groups (1-TTADORA2A + AA(CYP1A2); 2-TTADORA2A + AC/CCCYP1A2; 3-AA(CYP1A2) + CT/CCADORA2A;4-AC/CCCYP1A2 + CT/CCADORA2A). Using a randomized, crossover, counterbalanced, and double-blind design, participants ingested CAF (6 mg kg(-1)) or a placebo (PLA, 300 mg of cellulose) one hour before performing a sequence of physical tests: handgrip strength, agility test, countermovement jump (CMJ), Spike Jump (SJ), sit-ups, push-ups, and the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1). Results CAF enhanced handgrip strength (CAF: 35.0 +/- 9.2 kg force; PLA: 33.5 +/- 8.9 kg force; p = 0.050), CMJ height (CAF: 49.6 +/- 12.3 cm; PLA: 48.3 +/- 13.6 cm; p = 0.013), SJ height (CAF: 54.7 +/- 13.3 cm; PLA: 53.1 +/- 14.8 cm; p = 0.013), number of sit-ups (CAF: 37 +/- 8; PLA: 35 +/- 8; p = 0.001), and distance covered on the Yoyo IR1 test (CAF: 991.6 +/- 371.0 m; PLA: 896.0 +/- 311.0 m; p = 0.001), This CAF-induced improvement on exercise performance was, however, independent of genotypes groups (all p > 0.05). CAF had no effect on agility (CAF: 15.8 +/- 1.2 s; PLA: 15.9 +/- 1.3 s; p = 0.070) and push-up (CAF: 26.6 +/- 12.0; PLA: 25.0 +/- 11.0; p = 0.280) tests. Conclusion The acute caffeine intake of 6.0 mg.kg(-1) improves several aspects of physical performance, which seems to be independent of ADORA2A genotypes, alone or in combination with CYP1A2 genotypes.