Christopher D Black1, Dwight E Waddell, Alexander R Gonglach. 1. 1Department of Health and Exercise Science, University of Oklahoma, Norman, OK; 2Department of Health, Exercise Science, and Recreation Management, University of Mississippi, Oxford, MS; 3Department of Electrical Engineering, University of Mississippi, Oxford, MS.
Abstract
UNLABELLED: Caffeine improves endurance exercise performance, but its ergogenic mechanism(s) remain unclear. PURPOSE: This investigation sought to examine the effects of caffeine on perceptual and physiological responses to endurance exercise. METHODS: Two experiments were performed. In study A, 14 participants were tested. Maximal voluntary strength (MVC) and motor-unit recruitment (%ACT) of the knee extensors and elbow flexors were tested before and 60 min after ingestion of a 5-mg·kg⁻¹ dose of caffeine or placebo and after completion of 40 min of exercise (30 min of submaximal leg or arm cycling followed by a 10-min time-trial performance). Muscle pain, RPE, and cardiorespiratory variables were assessed throughout. To determine the effects of caffeine on muscle pain and RPE during high-intensity exercise, a second study (study B) was performed. Twelve participants exercised at 95% of their gas exchange threshold (GET) and at 70% of the difference between their GET and VO(2peak) (70%Δ) after caffeine and placebo ingestion. RESULTS: Compared to placebo, caffeine improved MVC (6.3%, P = 0.014) and %ACT (5.5%, P = 0.013) in the knee extensors, but not the elbow flexors, and reduced muscle pain (P < 0.05) and RPE (P < 0.05) during both submaximal cycling modalities. Caffeine ingestion improved time-trial performance during leg cycling (4.9% ± 6.5%, P = 0.03), but not arm crank cycling (2.1% ± 8.2%, P = 0.28), but the effect on pain and RPE was eliminated. Caffeine ingestion had no effect on pain or RPE during cycling at 95% GET and 70%Δ. CONCLUSIONS: Our results suggest that augmented strength and motor-unit recruitment, rather than reductions in pain and effort, may underlie caffeine's ergogenic effect on endurance exercise.
RCT Entities:
UNLABELLED: Caffeine improves endurance exercise performance, but its ergogenic mechanism(s) remain unclear. PURPOSE: This investigation sought to examine the effects of caffeine on perceptual and physiological responses to endurance exercise. METHODS: Two experiments were performed. In study A, 14 participants were tested. Maximal voluntary strength (MVC) and motor-unit recruitment (%ACT) of the knee extensors and elbow flexors were tested before and 60 min after ingestion of a 5-mg·kg⁻¹ dose of caffeine or placebo and after completion of 40 min of exercise (30 min of submaximal leg or arm cycling followed by a 10-min time-trial performance). Muscle pain, RPE, and cardiorespiratory variables were assessed throughout. To determine the effects of caffeine on muscle pain and RPE during high-intensity exercise, a second study (study B) was performed. Twelve participants exercised at 95% of their gas exchange threshold (GET) and at 70% of the difference between their GET and VO(2peak) (70%Δ) after caffeine and placebo ingestion. RESULTS: Compared to placebo, caffeine improved MVC (6.3%, P = 0.014) and %ACT (5.5%, P = 0.013) in the knee extensors, but not the elbow flexors, and reduced muscle pain (P < 0.05) and RPE (P < 0.05) during both submaximal cycling modalities. Caffeine ingestion improved time-trial performance during leg cycling (4.9% ± 6.5%, P = 0.03), but not arm crank cycling (2.1% ± 8.2%, P = 0.28), but the effect on pain and RPE was eliminated. Caffeine ingestion had no effect on pain or RPE during cycling at 95% GET and 70%Δ. CONCLUSIONS: Our results suggest that augmented strength and motor-unit recruitment, rather than reductions in pain and effort, may underlie caffeine's ergogenic effect on endurance exercise.
Authors: Nanci S Guest; Trisha A VanDusseldorp; Michael T Nelson; Jozo Grgic; Brad J Schoenfeld; Nathaniel D M Jenkins; Shawn M Arent; Jose Antonio; Jeffrey R Stout; Eric T Trexler; Abbie E Smith-Ryan; Erica R Goldstein; Douglas S Kalman; Bill I Campbell Journal: J Int Soc Sports Nutr Date: 2021-01-02 Impact factor: 5.150
Authors: Mark Glaister; Benjamin Henley Williams; Daniel Muniz-Pumares; Carlos Balsalobre-Fernández; Paul Foley Journal: PLoS One Date: 2016-08-17 Impact factor: 3.240