What Dose of Caffeine to Use: Acute Effects of 3 Doses of Caffeine on Muscle Endurance and Strength

Abstract

Purpose: To explore the effects of 3 doses of caffeine on muscle strength and muscle endurance. Methods: Twenty-eight resistance-trained men completed the testing sessions under 5 conditions: no-placebo control, placebo control, and with caffeine doses of 2, 4, and 6 mg·kg−1. Muscle strength was assessed using the 1-repetition-maximum test; muscle endurance was assessed by having the participants perform a maximal number of repetitions with 60% 1-repetition maximum. Results: In comparison with both control conditions, only a caffeine dose of 2 mg·kg−1 enhanced lower-body strength (d = 0.13–0.15). In comparison with the no-placebo control condition, caffeine doses of 4 and 6 mg·kg−1 enhanced upper-body strength (d = 0.07–0.09) with a significant linear trend for the effectiveness of different doses of caffeine (P = .020). Compared with both control conditions, all 3 caffeine doses enhanced lower-body muscle endurance (d = 0.46–0.68). For upper-body muscle endurance, this study did not find significant effects of caffeine. Conclusions: This study revealed a linear trend between the dose of caffeine and its effects on upper-body strength. The study found no clear association between the dose of caffeine and the magnitude of its ergogenic effects on lower-body strength and muscle endurance. From a practical standpoint, the magnitude of caffeine’s effects on strength is of questionable relevance. A low dose of caffeine (2 mg·kg−1)—for an 80-kg individual, the dose of caffeine in 1–2 cups of coffee—may produce substantial improvements in lower-body muscle endurance with the magnitude of the effect being similar to that attained using higher doses of caffeine.

CYP1A2 genotype and acute effects of caffeine on resistance exercise, jumping, and sprinting performance

“…The muscle endurance test used in this study further confirmed that caffeine ingestion is ergogenic for this fitness component in resistance-trained men. This study adds to the body of evidence showing improvements in muscle endurance following caffeine ingestion [28][29][30][31][32]. However, a more novel finding is that caffeine is ergogenic for power and velocity outputs when the number of repetitions between the caffeine and placebo conditions is matched.…”

“…However, as we demonstrated in the present study, even with an equal number of repetitions between conditions, caffeine might have still produced considerable improvements in the quality of the performed repetitions, that is, greater movement velocity and consequently, greater power output (which was not tested in the aforementioned studies). As compared to placebo, caffeine ingestion most commonly produced moderate improvements in the number of performed repetitions (generally one to three additional repetitions) [28,31]. We propose that in some contexts, improvements in the overall quality of the performed repetitions may be more important for training adaptations than simply performing a greater number of repetitions.…”

“…Specifically, we and two other studies that reported similar results utilized 3 mg/kg of caffeine. We opted to utilize a lower dose of caffeine as higher doses of caffeine do not seem to produce greater increases in performance [28]. In the study by Rahimi [13], the dose was considerably higher (i.e., 6 mg/kg).…”

ADORA2A C Allele Carriers Exhibit Ergogenic Responses to Caffeine Supplementation

“…Capsules were prepared in the laboratory by an experienced researcher while other researchers performed the blinding. Capsules were ingested 60 min before the start of the exercise session under the supervision of the research staff, as in previous research [1,26,27]. The participants' genotype was determined using a buccal swab.…”

Associations of coffee drinking with physical performance in the oldest-old community-dwelling men The Helsinki Businessmen Study (HBS)

“…Although habitual coffee drinking can enhance performance, the daily amount of coffee consumption in our older participants was relatively low [median] about two small cups or 220 g/day. As some studies have reported that athletes did not get extra benefit for their performance by consuming much higher amounts of coffee per day [19], a recent study showed that even low acute dose of caffeine (2 mg/ kg for 80 kg individual) that equal to approximately 200 g of coffee a day may produce substantial improvements in lower body muscle endurance [20]. Coffee also contains several bioactive compounds such as polyphenols and minerals and up to 1000 other bioactive components that could potentially affect performance and prevent chronic diseases.…”