Caffeine intake improves muscular endurance and induces depletion of anaerobic work capacity in the bench press

Abstract Aim: To investigate the effects of caffeine (CAF) ingestion on anaerobic work capacity (AWC) and muscular endurance in the bench press exercise at predictive intensities equivalent to 20, 25, and 30% of 1RM. Methods: Thirteen males (age: 23 ± 3 years; body mass 83.5 ± 4.9 kg; height 172.8 ± 5.0 cm and 1RM 82 ± 24 kg) had their 1RM test evaluated in the bench press exercise and the time until failure was performed at intensities equivalent to 20%, 25%, and 30% of 1RM to CAF (350mg) or placebo (PLA, cellulose). AWC was measured from the linear equation: "Force = Critical Force + (AWC x 1/timeout)". Results: CAF enhanced the time until failure at 20% of 1RM (PLA = 202.6 ± 29.1s; CAF = 243.2 ± 20.6s), but there was no ergogenic effect at 25% (PLA = 188.8 ± 23.5 s; CAF = 195.6 ± 27.1 s), and 30% (PLA = 147.4 ± 15.8 s; CAF = 145.4 ± 14.8 s). AWC in CAF was lower than PLA (PLA = 6378.0 ± 1214.9 J; CAF = 3246.4 ± 1389.7 J; p = 0.03; Effect size = 0.88). Critical Force (N) was not different between treatments PLA 29.97 ± 11.54% of 1RM and CAF 3.74 ± 3.69% of 1 RM (p=0.47; Effect size= 0.28). Conclusion: Acute CAF intake (350mg) reduces the AWC and increases the time until failure at 20% of 1 RM, but not Critical Force and muscular endurance at 25% and 30% of 1 RM in the bench press.

Caffeine mouth rinse has no effects on anaerobic energy yield during a Wingate Test.

BACKGROUND: The purpose was to investigate the effect of caffeine (CAF) mouth rinse on peak power (PP), mean power (MP), peak power relative to body mass (rel PP), mean power relative to body mass (rel MP), fatigue index (FI) and anaerobic contribution in the Wingate Test. METHODS: Ten healthy men (age: 24.8±3.7 years; body mass: 71.0±7.8 kg; height: 170±3 cm; body fat: 17.02±4.9%; VO2max: 44.15±5.5 ml·kg-1·min=) were recruited. A randomized, double-blind, cross-over design was employed. Participants were instructed to complete Wingate Test in the fastest time possible under 2 conditions: CAF (25 ml of mint syrup with 1.2% of CAF, equivalent to 300 mg of CAF) and placebo (PLA) (25 ml of mint syrup without CAF). RESULTS: There was no difference at PP (P=0.66), MP (P=0.16), rel PP (P=0.82), rel MP (P=0.18), FI (P=0.19), anaerobic alactic (P=0.71), anaerobic lactic (P=0.25), total energy expenditure (P=0.41) and peak plasma lactate concentration (P=0.57). CONCLUSIONS: CAF mouth rinse did not increase peak power (PP), mean power (MP), peak power relative to body mass (rel PP), mean power relative to body mass (rel MP), Fatigue Index (FI) nor anaerobic contribution in the Wingate Test.

Effect of Carbohydrate Mouth Rinse on Training Load Volume in Resistance Exercises.

Bastos-Silva, VJ, Prestes, J, and Geraldes, AAR. Effect of carbohydrate mouth rinse on training load volume in resistance exercises. J Strength Cond Res 33(6): 1654-1658, 2019-The aim of this study was to investigate the effect of carbohydrate (CHO) mouth rinse on training load volume (TLV-number of repetitions × load lifted [kg]) on 2 resistance exercises: leg press (LP) and bench press (BP). Twelve recreational resistance trained males were recruited. Subjects were assessed for 1 repetition maximum (1RM) and muscular endurance (ME) in LP and BP. Muscular endurance was determined by the maximum number of repetitions performed to volitional fatigue, with a load equal to 80% of 1RM. Exercises were performed on separate days (72 hours apart) under 3 experimental conditions: control (CONT), CHO (25 ml with 6.4% of maltodextrin), and placebo (juice without CHO [PLA]). Carbohydrate and PLA were used immediately before each exercise. There was no significant difference between conditions for the number of repetitions (CHO = 13.5 ± 4.8; PLA = 11.5 ± 4.4; CONT = 12.4 ± 4.4, p = 0.68) nor TLV (CHO = 2006.7 ± 825.2 kg; PLA = 1712.5 ± 772.9 kg; CONT = 1817.1 ± 672.6 kg, p = 0.99) in LP. However, CHO increased both repetitions (CHO = 8.2 ± 1.6; PLA = 7.1 ± 2.4; CONT = 6.8 ± 1.8, p = 0.002) and TLV (CHO = 557.1 ± 155.4 kg; PLA = 495.9 ± 206.1 kg; CONT = 476.1 ± 175.3 kg, p = 0.035) compared with CON in BP. Thus, a CHO mouth rinse increases BP performance in trained men, suggesting an interesting strategy to be used by experienced resistance training practitioners.