[Nick Voth is currently finishing his degree in Exercise Science from Bowling Green State University, where he competes on the Cross Country team. He is an Applied Sports Science Intern at Athletic Lab.]
As previously stated in Part One of this blog, Part Two will focus on carbohydrate (CHO) mouth rinsing for speed-power performance. Because CHO mouth rinsing enhances endurance exercise lasting approximately one hour via stimulation to pleasure and reward centers in the brain (Stellingwerff & Cox, 2014), it has been hypothesized that this same strategy can be used to increase shorter duration, high-intensity efforts. However, research regarding the potential benefits of CHO mouth rinsing on speed, strength, and power performance is conflicting.
Strength training has been studied with inconclusive results. Clarke et al. (2017) recently investigated the effects of a CHO mouth rinse on a wider range of high-intensity, short duration activities. Countermovement jump height, 10-meter sprint time, bench press, squat, and arousal were all enhanced with CHO mouth rinsing (Clarke et al., 2017). In line with that, Gant et al. (2010) found increased maximal voluntary force production following a CHO rinse. The results from Clarke et al. (2017) may be of practical significance because the study was conducted in the morning following an overnight fast. Athletes who train in the morning may not eat prior to a session. Revisiting the idea of fear of gastrointestinal distress, CHO mouth rinsing may provide a fueling solution while avoiding the ingestion of fuel.
On the other hand, CHO mouth rinsing was found to have no effect on maximal strength or strength endurance (Dunkin & Philips, 2017; Painelli et al., 2011). A possible explanation for the results observed by these studies resides in the ability of strength-trained athletes to produce greater motor unit activation (Ahtiainen & Häkkinen, 2009). It is possible that CHO mouth rinsing may have enhanced motivation aspects in the brain, however, in strength-trained individuals, it may not have been enough. Because these athletes already have greater neuromuscular capabilities, the CHO mouth rinse may not have provided enough stimulation to improve performance. Therefore, it would be reasonable to hypothesize that weaker athletes may find performance improvements from CHO rinsing (Painelli et al., 2011). Future research may wish to investigate this hypothesis, but nevertheless, it seems that it is still possible for CHO mouth rinsing to enhance strength performance.
Benefits of CHO mouth rinsing has also been seen in sprint performance. CHO mouth rinsing was found to significantly increase peak power output on cycling sprint performance (Phillips et al., 2014; Beaven et al., 2013). Beaven et al. (2013) reported greater power output in the first of five repeated sprint exercises, however, power decrements were greater with a CHO mouth rinse compared to a placebo. They suggested that the greater power achieved in the first sprint may come at a cost for later sprints due to increased depletion of ATP (Beaven et al., 2013). Subjects were only given 24 seconds of rest between sprints (Beaven et al., 2013). In sports for which athletes are given enough time for ATP regeneration, it is possible that the increase in peak power output can still be achieved with a CHO rinse prior to each performance period.
Shifting gears slightly, CHO mouth rinsing has cognitive benefits. While most research has focused on physiological implications of CHO mouth rinsing, it is important to understand that athletic performance is influenced by both physiological and psychological factors. While competing, athletes are forced to make important decisions that may influence the outcome of the competition. Pomportes et al. (2017) successfully demonstrated that CHO mouth rinsing significantly improves cognitive performance during exercise. Coaches need to be aware of this research because it can be useful for sports in which games or matches last a long time and place a high cognitive demand on athletes. They may be able to increase the decision-making processes of their athletes if they employ CHO mouth rinsing strategies during competition.
In conclusion to this blog, it is crucial to understand how and when to employ this fueling strategy. CHO mouth rinse solutions typically include maltodextrin, glucose, fructose, or lemon juice and last five to ten seconds in duration. More specifically, increasing duration of the CHO mouth rinse over the course of an exercise bout has not been found to provide a significant improvement in average or peak sprint performance (Tomko, 2017). The solution can be rinsed immediately prior and/or at pre-determined intervals during competition. For endurance athletes, this can mean employing the CHO mouth rinse at specific time intervals or mile marks. For track and field athletes, CHO mouth rinsing can be used between events. Lastly, for team sports athletes, CHO mouth rinsing can be used in competition breaks such as timeouts, halftime, or during a substitution. While the major advantage of using CHO mouth rinsing before or during competition is the decrease in gastrointestinal issues, CHO mouth rinsing strategies still need to be practiced in training. Athletes who plan to ingest fuel during performance often spend a great amount of time practicing and developing these strategies during training sessions to prepare their bodies to digest fuel during exercise. Digestion is not an issue with CHO mouth rinsing, but it should still be emphasized in training so that no issues arise on competition day.
Whether an athlete is new to developing fueling strategies for performance enhancement or is struggling with their current plan, CHO mouth rinsing may be the answer. This fueling strategy is easy to employ and takes little time. Despite some conflicting research, athletes across all disciplines could benefit from CHO mouth rinsing and should consider this strategy when developing a fueling plan for an upcoming competition.
Ahtiainen, J.P., & Häkkinen, K. (2009). Strength athletes are capable to produce greater muscle activation and neural fatigue during high-intensity resistance exercise than nonathletes. Journal of Strength and Conditioning Research, 23(4), 1129-1134. doi: 10.1519/JSC.0b013e3181aa1b72
Beaven, C.M., Maulder, P., Pooley, A., Kilduff, L., & Cook, C. (2013). Effects of caffeine and carbohydrate mouth rinses on repeated sprint performance. Applied Physiology, Nutrition, and Metabolism, 38(6), 633-637. doi: 10.1139/apnm-2012-0333
Clarke, N.D., Hammond, S., Kornilios, E., Mundy, P.D. (2017). Carbohydrate mouth rinse improves morning high-intensity exercise performance. European Journal of Sport Science, 1-9. doi: 10.1080/17461391.2017.1333159
Dunkin, J.E., & Philips, S.M. (2017). The effect of a carbohydrate mouth rinse on upper-body muscular strength and endurance. Journal of Strength and Conditioning Research, 31(7), 1948-1953. doi: 10.1519/JSC.0000000000001668
Gant, N., Stinear, C.M., & Byblow, W.D. (2010). Carbohydrate in the mouth immediately facilitates motor output. Brain Research, 1350, 151-158. Retrieved from https://doi.org/10.1016/j.brainres.2010.04.004
Painelli, V.S., Roschel, H., Gualano, B., Del-Favero, S., Benatti, F.B., Ugrinowitsch, C., Tricoli, V., & Lancha, A.H. (2011). The effect of carbohydrate mouth rinse on maximal strength and strength endurance. European Journal of Applied Physiology, 111(9), 2381-2386). doi: 10.1007/s00421-011-1865-8
Phillips, S.M., Findlay, S., Kavaliauskas, M., & Grant, M.C. (2014). The Influence of serial carbohydrate mouth rinsing on power output during a cycle sprint. Journal of Sports Science & Medicine, 13(2), 252–258. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3990876/
Pomportes, L., Brisswalter, J., Casini, L., Hays, A., & Davranche, K. (2017). Cognitive performance enhancement induced by caffeine, carbohydrate and guarana mouth rinsing during submaximal exercise. Nutrients, 9(6), 589-606. doi: 10.3390/nu9060589
Tomko, P. (2017). Carbohydrate mouth rinsing duration impact on fatigue and recovery from repeated sprint exercise (Master’s thesis). Retrieved from https://etd.ohiolink.edu/!etd.send_file?accession=bgsu1491336901621137&disposition=inline