Effects of acute caffeine ingestion on muscle strength, muscular endurance, rating of perceived exertion, and pain perception during strength exercise until the failure

PurposeWe aimed to examine the effects of acute caffeine ingestion on muscular strength, muscular endurance, rating of perceived exertion (RPE) and pain perception (PP) during strength exercise to failure.MethodsThirteen subjects (6 males, 7 females, 21.30 & PLUSMN; 0.71 years) participated in this randomized, double-blind, controlled experimental study. Participants ingested caffeine capsules (5 mg kg(-1)) or placebo 1 h before a resistance exercise session at 90% 1RM and 50% 1RM, separated by at least 48 h.ResultsThe number of repetitions performed in the first and second series at 90% of 1RM of the bench press was significantly higher (p < 0.05) in the caffeine condition than the placebo. In the back squat, the first set in the caffeine condition was significantly greater (p < 0.05) in comparison to placebo. At 50% 1RM, the number of repetitions was higher in the caffeine session than the placebo in the bench press, back squat and leg press exercises (p < 0.05). RPE at 50% 1RM was lower (p < 0.05) in the caffeine session compared to the placebo session in the bench press, back squat, and supine row. The PP at 90% of 1RM was lower (p < 0.05) in the bench press in the first and second series about the placebo session.ConclusionIn conclusion, caffeine intake can be used to obtain greater performance in strength training with lower PP and muscular endurance with lower RPE.