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Carbohydrate Mouth Rinsing Enhances High Intensity Time Trial Performance Following Prolonged Cycling

View Article: PubMed Central - PubMed

ABSTRACT

There is good evidence that mouth rinsing with carbohydrate (CHO) solutions can enhance endurance performance (≥30 min). The impact of a CHO mouth rinse on sprint performance has been less consistent, suggesting that CHO may confer benefits in conditions of ‘metabolic strain’. To test this hypothesis, the current study examined the impact of late-exercise mouth rinsing on sprint performance. Secondly, we investigated the effects of a protein mouth rinse (PRO) on performance. Eight trained male cyclists participated in three trials consisting of 120 min of constant-load cycling (55% Wmax) followed by a 30 km computer-simulated time trial, during which only water was provided. Following 15 min of muscle function assessment, 10 min of constant-load cycling (3 min at 35% Wmax, 7 min at 55% Wmax) was performed. This was immediately followed by a 2 km time trial. Subjects rinsed with 25 mL of CHO, PRO, or placebo (PLA) at min 5:00 and 14:30 of the 15 min muscle function phase, and min 8:00 of the 10-min constant-load cycling. Magnitude-based inferential statistics were used to analyze the effects of the mouth rinse on 2-km time trial performance and the following physiological parameters: Maximum Voluntary Contract (MVC), Rating of Perceived Exertion (RPE), Heart Rate (HR), and blood glucose levels. The primary finding was that CHO ‘likely’ enhanced performance vs. PLA (3.8%), whereas differences between PRO and PLA were unclear (0.4%). These data demonstrate that late-race performance is enhanced by a CHO rinse, but not PRO, under challenging metabolic conditions. More data should be acquired before this strategy is recommended for the later stages of cycling competition under more practical conditions, such as when carbohydrates are supplemented throughout the preceding minutes/hours of exercise.

No MeSH data available.


Related in: MedlinePlus

Experimental trial design with dependent measures. Water intake bracket indicates when only water was provided; HR+ with short arrow indicates heart rate (HR), rating of perceived exertion (RPE), and glucose measurements taken midway through the 30 km time trial (TT) prior to the mouth rinse (MR) intervention; HR+ with tall arrow indicates HR, RPE, and glucose measurements taken to determine the effects of the MR intervention; MVC, maximum voluntary.
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nutrients-08-00576-f001: Experimental trial design with dependent measures. Water intake bracket indicates when only water was provided; HR+ with short arrow indicates heart rate (HR), rating of perceived exertion (RPE), and glucose measurements taken midway through the 30 km time trial (TT) prior to the mouth rinse (MR) intervention; HR+ with tall arrow indicates HR, RPE, and glucose measurements taken to determine the effects of the MR intervention; MVC, maximum voluntary.

Mentions: The study was carried out in a counterbalanced, double-blinded fashion, with trials separated by seven to 10 days each. Following cardiorespiratory fitness testing, subjects completed 1 familiarization trial and three experimental trials on the aforementioned cycle ergometer. Each trial consisted of: 120 min of constant-load cycling at 55% Wmax, a simulated 30 km time trial (TT) (~57 min), 15 min of rest that included peak isometric force testing, 10 min of constant-load cycling (3 min at 35% Wmax and 7 min at 55% Wmax), and a computer simulated 2 km time trial (~4 min) (Figure 1). The inclusion of a variable and self-selected intensity 30 km time trial prior to the mouth rinse intervention instead of continuing constant-load cycling allowed us to assess 30 km TT reliability under placebo (water) conditions, as we have reported elsewhere [32]. This decision may have introduced additional variability for subsequent measures, though data gathered during the 30 km TT and finishing times indicate that subjects experienced similar physiological stimuli prior to each of the three MR treatments.


Carbohydrate Mouth Rinsing Enhances High Intensity Time Trial Performance Following Prolonged Cycling
Experimental trial design with dependent measures. Water intake bracket indicates when only water was provided; HR+ with short arrow indicates heart rate (HR), rating of perceived exertion (RPE), and glucose measurements taken midway through the 30 km time trial (TT) prior to the mouth rinse (MR) intervention; HR+ with tall arrow indicates HR, RPE, and glucose measurements taken to determine the effects of the MR intervention; MVC, maximum voluntary.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037560&req=5

nutrients-08-00576-f001: Experimental trial design with dependent measures. Water intake bracket indicates when only water was provided; HR+ with short arrow indicates heart rate (HR), rating of perceived exertion (RPE), and glucose measurements taken midway through the 30 km time trial (TT) prior to the mouth rinse (MR) intervention; HR+ with tall arrow indicates HR, RPE, and glucose measurements taken to determine the effects of the MR intervention; MVC, maximum voluntary.
Mentions: The study was carried out in a counterbalanced, double-blinded fashion, with trials separated by seven to 10 days each. Following cardiorespiratory fitness testing, subjects completed 1 familiarization trial and three experimental trials on the aforementioned cycle ergometer. Each trial consisted of: 120 min of constant-load cycling at 55% Wmax, a simulated 30 km time trial (TT) (~57 min), 15 min of rest that included peak isometric force testing, 10 min of constant-load cycling (3 min at 35% Wmax and 7 min at 55% Wmax), and a computer simulated 2 km time trial (~4 min) (Figure 1). The inclusion of a variable and self-selected intensity 30 km time trial prior to the mouth rinse intervention instead of continuing constant-load cycling allowed us to assess 30 km TT reliability under placebo (water) conditions, as we have reported elsewhere [32]. This decision may have introduced additional variability for subsequent measures, though data gathered during the 30 km TT and finishing times indicate that subjects experienced similar physiological stimuli prior to each of the three MR treatments.

View Article: PubMed Central - PubMed

ABSTRACT

There is good evidence that mouth rinsing with carbohydrate (CHO) solutions can enhance endurance performance (≥30 min). The impact of a CHO mouth rinse on sprint performance has been less consistent, suggesting that CHO may confer benefits in conditions of ‘metabolic strain’. To test this hypothesis, the current study examined the impact of late-exercise mouth rinsing on sprint performance. Secondly, we investigated the effects of a protein mouth rinse (PRO) on performance. Eight trained male cyclists participated in three trials consisting of 120 min of constant-load cycling (55% Wmax) followed by a 30 km computer-simulated time trial, during which only water was provided. Following 15 min of muscle function assessment, 10 min of constant-load cycling (3 min at 35% Wmax, 7 min at 55% Wmax) was performed. This was immediately followed by a 2 km time trial. Subjects rinsed with 25 mL of CHO, PRO, or placebo (PLA) at min 5:00 and 14:30 of the 15 min muscle function phase, and min 8:00 of the 10-min constant-load cycling. Magnitude-based inferential statistics were used to analyze the effects of the mouth rinse on 2-km time trial performance and the following physiological parameters: Maximum Voluntary Contract (MVC), Rating of Perceived Exertion (RPE), Heart Rate (HR), and blood glucose levels. The primary finding was that CHO ‘likely’ enhanced performance vs. PLA (3.8%), whereas differences between PRO and PLA were unclear (0.4%). These data demonstrate that late-race performance is enhanced by a CHO rinse, but not PRO, under challenging metabolic conditions. More data should be acquired before this strategy is recommended for the later stages of cycling competition under more practical conditions, such as when carbohydrates are supplemented throughout the preceding minutes/hours of exercise.

No MeSH data available.


Related in: MedlinePlus