The purpose of the present study was to compare the effects of carbohydrate-electrolyte-protein solutions (CEPS), carbohydrate-electrolyte solutions (CES), and placebo (PLA) consumption on 21 km running performance in female runners. Nine healthy recreational female marathon runners (Age 36±7 y, BMI 21.0±2.3 kg/m2, VO2max 48.4±6.8 ml/kg/min) completed 3 experimental trials in a randomized crossover study design, separated by at least 30 days. All the main trials were required to be finished in their follicular phase. In each main trial, participants were required to complete one 21 km performance running. For the first 5 km, the participants ran at a fixed speed of their individual 70% VO2max. Thereafter, the participants ran at whatever speed they wished for the remaining 16 km of the performance run. Every 2.5 km throughout the run, 150 ml of solutions was provided to the participants. The three solutions were CES (6%CHO), CEPS (4%CHO+2%PRO), and a non-caloric, artificially sweetened PLA. Three solutions contained the same electrolyte profile. Total energy was matched between CES and CEPS. No differences was found in remaining 16 km running performance among the three trials, with mean times of 103.3±3.1, 98.7±1.9, and 103.1±2.9 min for CEPS, CES and PLA trials, respectively. Blood glucose concentration was lower in PLA trial (4.5±0.1 mmol/L) than CES trial (5.6±0.2 mmol/L) (P=0.004). Blood lactate was higher in CES trial (2.5±0.3 mmol/L) than CEPS trial (1.8±0.2 mmol/L) (P=0.043). It seems that neither CES nor CEPS consumption during a 21 km run can improve exercise performance in recreational female marathon runners.
The present study was supported by Dean's Research Fund (FLASS/DRF/ECR-2), Faculty of Liberal Arts and Social Sciences, The Education University of Hong Kong.