AUTHOR=Aandahl Mats Holst , Noordhof Dionne A. , Tjønna Arnt Erik , Sandbakk Øyvind 

TITLE=Effect of Carbohydrate Content in a Pre-event Meal on Endurance Performance-Determining Factors: A Randomized Controlled Crossover-Trial

JOURNAL=Frontiers in Sports and Active Living

VOLUME=3

YEAR=2021

URL=https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2021.664270

DOI=10.3389/fspor.2021.664270

ISSN=2624-9367

ABSTRACT=<p>The current study aimed to investigate the effect of the relative CHO content in a pre-event meal on time to exhaustion (TTE), peak oxygen uptake (<inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mrow><mml:mtext>V</mml:mtext></mml:mrow><mml:mo>∙</mml:mo></mml:mover><mml:msub><mml:mrow><mml:mtext>O</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mtext>peak</mml:mtext></mml:mrow></mml:msub></mml:math></inline-formula>), the 2nd lactate threshold (LT2), onset of blood lactate accumulation (OBLA), and work economy (WE) and to compare responses between well-trained and recreationally trained individuals. Eleven well-trained and 10 recreationally trained men performed three trials in a randomized cross-over design, in which they performed exercise tests (1) after a high-CHO pre-event meal (3 g · kg<sup>−1</sup>), (2) a low-CHO pre-event meal (0.5 g · kg<sup>−1</sup>), or (3) in a fasted-state. The test protocol consisted of five submaximal 5-min constant-velocity bouts of increasing intensity and a graded exercise test (GXT) to measure TTE. A repeated measure ANOVA with a between-subjects factor (well-trained vs. recreational) was performed. A main effect of pre-event meal was found (<italic>p</italic> = 0.001), with TTE being 8.0% longer following the high-CHO meal compared to the fasted state (<italic>p</italic> = 0.009) and 7.2% longer compared to the low-CHO meal (<italic>p</italic> = 0.010). No significant effect of pre-event meal on <inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mrow><mml:mtext>V</mml:mtext></mml:mrow><mml:mo>∙</mml:mo></mml:mover><mml:msub><mml:mrow><mml:mtext>O</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mtext>peak</mml:mtext></mml:mrow></mml:msub></mml:math></inline-formula>, LT2, OBLA, or WE (<italic>p</italic> ≥ 0.087) was found and no significant interaction effect between training status and pre-event CHO intake was found for TTE or any of the performance-determining variables (<italic>p</italic> ≥ 0.257). In conclusion, high-CHO content in the pre-event meal led to a longer TTE compared to a meal with a low-CHO content or exercising in a fasted state, both in well-trained and recreationally trained participants. However, the underlying physiological reason for the increased TTE is unclear, as no effect of pre-event meal on the main physiological performance-determining variables was found. Thus, pre-event CHO intake should be standardized when the goal is to assess endurance performance but seems to be of less importance when assessing the main performance-determining variables.</p>