Dunkin, JE and Phillips, SM. The effect of a carbohydrate mouth rinse on upper-body muscular strength and endurance. J Strength Cond Res 31(7): 1948–1953, 2017—Carbohydrate (CHO) mouth rinsing rapidly increases corticomotor output and maximal muscle force production, which could enhance muscular strength and endurance during resistance exercise. However, previous research has found no effect of CHO rinsing on muscular strength or endurance. The current study altered the CHO rinse composition and frequency and the muscular endurance test to further investigate the effects of a CHO mouth rinse on upper-body muscular strength and endurance. Twelve recreationally resistance-trained men (mean ± SD age 22 ± 1 year, height 179.2 ± 1.8 cm, body mass 80.9 ± 6.1 kg) completed a bench press protocol (1 repetition maximum [RM] test followed by repetitions to failure at 40% of 1RM) on 3 occasions. Subjects rinsed 25 ml of an 18% CHO solution or a placebo for 10 seconds before 1RM and repetitions to failure and completed a no-rinse control condition. Felt arousal (FA) was measured before and after each rinse, heart rate (HR) was measured before and after both exercise protocols, and rating of perceived exertion (RPE) was recorded after repetitions to failure. Rinsing did not influence 1RM (p = 0.680,
= 0.03), repetitions to failure (p = 0.677,
= 0.04), or exercise volume (load × reps; p = 0.600,
= 0.05). There were no significant treatment effects on heart rate (p = 0.677,
= 0.04), FA (p = 0.674,
= 0.04) or rating of perceived exertion (p = 0.604,
= 0.05). A CHO mouth rinse does not improve upper-body muscular strength or endurance.