Abstract
Background: Caffeine is an ergogenic aid shown to delay fatigue, increase arousal, and improve performance. Recommended doses are 3-6 mg/kg BM, although evidence supports lower doses (<3 mg/kg). Some conflicting results have highlighted that lower doses may still be ergogenic, and with new pouch and gum products, further research is warranted. Method: This study investigated the effects of novel low-dose caffeine products on muscular endurance, strength, and power. A repeated-measure, crossover design (pouch 80 mg, gum 80 mg, control gum 0 mg) was employed, recruiting nineteen participants (age 22.4 + 4.8 yrs; weight 72.8 + 16.9 kg; relative caffeine dose 1.1 mg/kg). Participants completed a battery of tests, including 60% 1 RM single leg press (LP) and shoulder press (SP) to exhaustion, counter-movement jump, and isometric mid-thigh pull, in addition to providing ratings of perceived exertion (RPE) during endurance tests. One-way repeated measures ANOVA was conducted on all measures associated with physical tasks, with a two-way repeated measures ANOVA conducted for RPE. Results: No significance was observed among conditions for physical tests. However, effect sizes, employing Cohen's D classification, identified a moderate (d = 0.55) and small (d = 0.45) effect for the caffeine pouch compared to the placebo and caffeine gum for the LP respectively. Further, small effects for the pouch compared to the placebo were observed (d = 0.33) for the SP. Significant differences were produced for RPE during the LP (p = 0.022), with post hoc analysis identifying significant differences between the placebo vs. caffeine pouch (p = 0.032). Conclusion: Low-dose caffeine has the potential to produce meaningful effects on strength endurance, likely linked to caffeine mechanisms reducing RPE.