The aim was to investigate the influence of a carbohydrate (CHO) mouth rinse on the vastus lateralis (VL) and rectus femoris (RF) electromyographic activity (EMG) and time to exhaustion (TE) during moderate (MIE) and high-intensity cycling exercise (HIE). Thirteen participants cycled at 80% of their respiratory compensation point and at 110% of their peak power output to the point of exhaustion. Before the trials and every 15 min during MIE, participants rinsed with the CHO or Placebo (PLA) solutions. The root mean square was calculated. CHO had no effect on the TE during HIE (CHO: 177.3 ± 42.2 s; PLA: 163.0 ± 26.7 s, p = 0.10), but the TE was increased during MIE (CHO: 76.6 ± 19.7 min; PLA: 65.4 ± 15.2 min; p = 0.01). The EMG activity in the VL was higher than PLA at 30 min (CHO: 10.5% ± 2.6%; PLA: 7.7% ± 3.3%; p = 0.01) and before exhaustion (CHO: 10.3% ± 2.5%; PLA: 8.0% ± 2.9%; p = 0.01) with CHO rinsing. There was no CHO effect on the EMG activity of RF during MIE or for VL and RF during HIE. CHO mouth rinse maintains EMG activity and enhances performance for MIE but not for HIE.

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.

Objective The aim of this study was to analyze the effects of carbohydrate ingestion prior to exercise on the number of bench press repetitions. Methods Eight male physically active (21.3±2.7 years, 176±5cm, 73.12±6.12kg), with a minimum experience of at least one year exercising regularly, visited the laboratory at three moments. During the first visit, candidates went through their anthropometric evaluation and the application of their maximum number of bench press repetitions. The experimental tests were performed during their second and third visits in a crossover and blind study. The participants performed the maximum number of repetitions with an intensity of 70% of their maximum repetition strength. One hour before the experimental trials, participants randomly ingested a solution containing either carbohydrate or a placebo. Results The ingestion of carbohydrate increases muscle resistance in relation to placebo (p=0.014; effect size=0.71). This is evidenced by the increase in the number of repetitions (12.9±2.4 and 11.3±1.9, respectively). The individual’s perception of effort is higher in the carbohydrate group than in the placebo group after exhaustion (4±0.93 and 3.1±0.64, respectively, p=0.006, effect size=0.89). Conclusion It is concluded that a previous intake of carbohydrate is useful in improving performance in resistance exercises, providing an increase in the individual’s perception of effort.

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We investigated the effects of caffeine mouth rinse on endurance performance, muscle recruitment (i.e., electromyographic activity of the vastus lateralis and rectus femoris), rating of perceived effort and heart rate. Twelve physically-active healthy men cycled at 80% of their respiratory compensation point until task failure. The participants rinsed their mouths for 10 seconds with placebo (PLA, 25 mL of a solution composed of non-caloric mint essence) or caffeine (CAF, 25 mL of 1.2% of anhydrous caffeine concentration with non-caloric mint essence) every 15 minutes of exercise. Time until exhaustion increased 17% (effect size = 0.70) in CAF compared to PLA (p = 0.04). The wavebands of low-frequency electromyographic activity (EMG) of the vastus lateralis and rectus femoris was lower in CAF group than PLA at 50% of the time until exhaustion (p = 0.04). The global EMG signal was lower in CAF group than PLA at 100% of the time until exhaustion (p = 0.001). The rating of perceived effort pooled was higher in CAF mouth rinse (p = 0.001) than PLA group. No effect was found on the heart rate between the groups (p > 0.05). Caffeine mouth rinse increases endurance performance, rating of perceived effort and decreases muscle activity during a moderate-intensity exercise.