Muscular endurance
upper-body muscular endurance
STILL
Caffeine alone and caffeine co-ingested with CitMal improved lower-body and upper-body muscular endurance with a moderate effect size. While an ergogenic effect was found in both conditions, there were no differences between isolated caffeine vs. caffeine and CitMal combined.An ergogenic effect of caffeine on muscular endurance has been commonly observed in the literature. For example, Norum et al. [We did not detect a significant effect of isolated CitMal ingestion on muscular endurance. Still, it should be mentioned that the mean difference highly favored the CitMal condition compared to placebo. Mean differences favored CitMal in the squat by 1.9 repetitions (95% confidence interval: − 0.3, 4.0 repetitions) and in the bench press by 1.2 repetitions (95% confidence interval: − 0.04, 2.4 repetitions). In line with our findings, a recent meta-analysis by Vårvik et al. [The results in the present study suggest that the combination of caffeine and CitMal is not likely to have additive ergogenic effects on muscular endurance. There are several possible reasons for such a lacking additive effect. First, when compared to placebo, isolated CitMal was not found to be ergogenic—even though the effects highly favoured the CitMal condition. Given that CitMal did not demonstrate significant ergogenic effects in isolation, it seems logical that adding this supplement to caffeine would not yield greater performance benefits than ingesting caffeine alone in our study. Nevertheless, since the potential ergogenic effect of CitMal on muscular endurance appears to be very small [