Effect of Various Carbohydrate-Electrolyte Fluids on Cycling Performance and Maximal Voluntary Contraction

• Published in: International journal of sport nutrition and exercise metabolism 2010-04, Vol.20 (2), p.104-114
• Main Authors: Ganio, Matthew S, Klau, Jennifer F, Lee, Elaine C, Yeargin, Susan W, McDermott, Brendon P, Buyckx, Maxime, Maresh, Carl M, Armstrong, Lawrence E
• Format: Article
• Language: English
• Subjects: Adult; adults; athletes; Athletic Performance; beverages; bicycling; Bicycling - physiology; caffeine; Caffeine - administration & dosage; carbohydrate content; carnitine; Carnitine - administration & dosage; central nervous system; Cross-Over Studies; Dietary Carbohydrates - administration & dosage; Dietary Carbohydrates - pharmacology; Double-Blind Method; electrolytes; Electrolytes - administration & dosage; Electrolytes - pharmacology; energy expenditure; energy metabolism; Humans; Isometric Contraction - drug effects; Isometric Contraction - physiology; Male; men; muscle contraction; muscle strength; Muscle, Skeletal - physiology; rating of perceived exertion; Rehydration Solutions - administration & dosage; Rehydration Solutions - pharmacology; skeletal muscle; Task Performance and Analysis; taurine; Taurine - administration & dosage; vitamin B complex; Vitamin B Complex - adverse effects; Water-Electrolyte Balance - physiology
• ISSN: 1526-484X; 1543-2742
• DOI: 10.1123/ijsnem.20.2.104

The purpose of this study was to compare the effects of a carbohydrate-electrolyte plus caffeine, carnitine, taurine, and B vitamins solution (CE+) and a carbohydrate-electrolyte-only solution (CE) vs. a placebo solution (PLA) on cycling performance and maximal voluntary contraction (MVC). In a randomized, double-blind, crossover, repeated-measures design, 14 male cyclists (M ± SD age 27 ± 6 yr, VO(2max) 60.4 ± 6.8 ml · kg–1 · min–1) cycled for 120 min submaximally (alternating 61% ± 5% and 75% ± 5% VO(2max)) and then completed a 15-min performance trial (PT). Participants ingested CE+, CE, or PLA before (6 ml/kg) and every 15 min during exercise (3 ml/kg). MVC was measured as a single-leg isometric extension (70° knee flexion) before (pre) and after (post) exercise. Rating of perceived exertion (RPE) was measured throughout. Total work accumulated (KJ) during PT was greater (p < .05) in CE+ (233 ± 34) than PLA (205 ± 52) but not in CE (225 ± 39) vs. PLA. MVC (N) declined (p < .001) from pre to post in PLA (988 ± 213 to 851 ± 191) and CE (970 ± 172 to 870 ± 163) but not in CE+ (953 ± 171 to 904 ± 208). At Minutes 60, 90, 105, and 120 RPE was lower in CE+ (14 ± 2, 14 ± 2, 12 ± 1, 15 ± 2) than in PLA (14 ± 2, 15 ± 2, 14 ± 2, 16 ± 2; p < .001). CE+ resulted in greater total work than PLA. CE+, but not PLA or CE, attenuated pre-to-post MVC declines. Performance increases during CE+ may have been influenced by lower RPE and greater preservation of leg strength during exercise in part as a result of the hypothesized effects of CE+ on the central nervous system and skeletal muscle.