Carbohydrate and caffeine mouth rinses do not affect maximum strength and muscular endurance performance

Oral carbohydrate rinsing has beneficial effects on endurance performance and caffeine mouth rinsing either independently or in conjunction with carbohydrate may enhance sprinting performance. However, the effects of carbohydrate and/ or caffeine mouth rinses on resistance exercise have not been examined previously. The purpose of this study was to investigate the effects of carbohydrate and/ or caffeine rinsing on maximum strength and muscular endurance performance. Fifteen recreationally resistance trained males completed an exercise protocol which involved a one repetition maximum (1-RM) bench press followed by 60% of their 1-RM to failure in a double-blind, randomised, counterbalanced crossover design. Prior to exercise either 25 ml of a 6% (15 g; 0.20+/-0.02 g[middle dot]kg-1) carbohydrate (CHO), 1.2% (300 mg; 3.9+/-0.3 mg[middle dot]kg-1) caffeine (CAF), carbohydrate with caffeine (C+C) solutions, or water (PLA) were rinsed for 10 s. During the remaining session, no solution was rinsed (CON). All solutions were flavoured with (200 mg) sucralose. Felt arousal was recorded pre- and post-rinse and rating of perceived exertion was recorded immediately after the repetitions to failure. There were no significant differences in 1-RM (P=0.808; [eta]p2=0.02), the number of repetitions performed (P=0.682; [eta]p2=0.03) or the total exercise volume (P=0.482; [eta]p2=0.03) between conditions. RPE was similar for all trials (P=0.330; [eta]p2=0.08), while Felt arousal increased as a consequence of rinsing (P=0.001; [eta]p2=0.58), but was not different between trials (P=0.335; [eta]p2=0.08). These results suggest that rinsing with a carbohydrate and caffeine solution either independently or combined has no significant effect on maximum strength or muscular endurance performance.