Discussion
This study investigated whether the competitive level and sex may influence the acute effects of CAF intake on taekwondo-specific performances. The main findings suggest that elite and sub-elite athletes of both sexes experienced ergogenic benefits from CAF when compared to PLA and CON conditions and that males performed better compared to females regardless of competitive level and/or condition. In addition, males performed better in agility compared to females in PLA and CAF conditions. Even though the distinct mechanisms underpinning these results are not fully known, data suggest that performance enhancement during taekwondo with CAF ingestion is intimately dependent on the competitive level mainly for female athletes. Specifically, while the magnitude of performance improvement from CAF intake was comparable across elite and sub-elite male athletes (difference only in FSKT-10s), elite female athletes showed greater magnitudes of gains from CAF intake than sub-elite females for both TSAT and FSKT-10s. As well, elite and sub-elite males with CAF elicited better performance than elite and sub-elite females for TSAT and FSKT-10s.The results of the present study showing improved agility and kicking performance with CAF ingestion are comparable to those previously reported in other investigations on combat sportsThe present study provides novel insights into how CAF influences exercise performance related to the competitive level of female athletes. Due to the influence of body composition, aerobic capacity, and some anaerobic measures that are mediated by hormonal fluctuations, sex has been recognized as a significant factor in determining athletic performanceSex has also been suggested to moderate the link between CAF supplementation and arousal alterationsRegarding the competitive level, due to the high performance and capabilities of highly trained individuals, it was questioned if performance can be further enhanced following CAF ingestionThe ergogenic effects of caffeine on exercise performance appear to be predominantly related to CAF’s binding to adenosine receptorsThe main strength of the current study was that we employed a double-blind, randomized, placebo-controlled crossover study design to examine the influence of caffeine on athletes’ performance using sports-specific tests (reflecting the mechanical actions, activity patterns and metabolic demands of the sport), and in relation to sex and competition level. Nevertheless, several aspects require further consideration. While the results demonstrate the ergogenic potential of caffeine on performance in taekwondo-specific tests, and differences in its ergogenicity between competitive levels and sexes, its translation to performance in competition or simulated competition remains to be fully elucidated. Furthermore, we did not attempt to quantify the physiological mechanisms underlying caffeine’s performance improvement or variation in the responses between competitive level and sex. Differences in body mass and body composition between sexes could mean that females received a more potent dose of caffeine than males