HIEC test
peripheral fatigue, hypertrophy, fatigue
HYPERTROPHY
Participants experienced a significant increase in time to fatigue with the supplement compared to the placebo, with an average increase in time to fatigue of 36.2%. The observed effects are likely attributed to enhanced power production that allowed the participants to cycle at a higher intensity for longer without fatigue. The present study did not assess changes in lean tissue mass; therefore, it is unclear if the supplement enhanced muscle functionality in the absence of hypertrophy. Future studies could assess this aspect noninvasively by using ultrasonography to image muscle structure and examine change in the muscle to better understand the effects of supplementation on performance measures.The BCAAs contained in the supplement likely improved time to fatigue by serving as an energy substrate contributing to improved peripheral fatigue factors and by delaying central fatigue. Glucose is used as a major energy source during exercise; however, it is suggested that amino acids contribute approximately 5% of energy source during exercise (with ranges estimated up to 20% based on factors such as carbohydrate availability and sex) [Kephart et al. [There was no improvement in VAS responses with the test supplement. The HIEC test is designed for the participant to go until complete exhaustion; therefore, it was expected that participants would report similarly regarding perceived exertion upon completion of each testing session.