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

ABSTRACT

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 CADORA2A allele carriers) and 163 C > A CYP1A2 (AA homozygous or CCYP1A2 allele carriers). Participants were further divided in four groups (1-TTADORA2A + AACYP1A2; 2-TTADORA2A + AC/CCCYP1A2; 3-AACYP1A2 + 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.