ABSTRACT
Objective To compare the effect of a carbohydrate-electrolyte-protein solution (CEPS,2％ protein plus 4％ carbohydrate),carbohydrate-electrolyte solution (CES,6％ carbohydrate),and non-caloric sweetened placebo (PLA)on 21 km running performance of female recreational marathon runners.Methods In a randomized cross-over design,12 female recreational marathon runners (age:33.4 ± 2.1 years,body mass index:21.10 ± 0.6 kg/m2,and maximal oxygen consumption:48.5 ± 1.9 mL/kg/min)performed a 21 km time trial (TT)run on three occasions separated by at least 28 days.During the first 5 km,participants ran on the treadmill with 70％VO2max.Thereafter,the participants ran at whatever speed they wished for the remaining 16 km of the performance run.In each main trial,participants ingested the CEPS,CES,or PLA at a rate of 150 mL every 2.5 km.The blood samples,gas samples,heart rate,core temperature,and subjective measures were conducted every 5 km throughout the exercise.Results Time of TT run completion was slightly shorter (P ＜ 0.05)in the CES trial (97.8 ±1.6 min)than in the PLA trial (102.4 ± 2.4 min),with no significant differences between the CEPS trial (100.7 ± 2.9 min)and the other two trials (P＞0.05).There were no differences in core temperature,blood lactate,heart rate,CHO oxidation rate,fat oxidation rate,CHO oxidation amount,and fat oxidation amount among the different trials (all P＞0.05).The average blood glucose was higher in CES trial than PLA trial (P＜0.05).The average respiratory exchange rate was higher in CEPS trim than PLA trial (P＜0.05).Conclusion Compared with ingesting the PLA,ingesting the 6％ CES improves the 21 km TT run performance in recreational female runners.However,no additional benefit of CEPS was observed on endurance performance.
ABSTRACT
Objective Based on the model of exercise induced central fatigue,we attempt to testify that the whole power output in time-counted sporting events was regulated by the central nervous system(CNS).Methods Eighteen national level rowers participated in the experiment.Each participant completed two successive 6 minutes maximal rowing exercise with an interval of 15 minutes.The power output(PO),heart rate(HR),blood lactate(BL),RPE and EMG were measured.Results It was demonstrated that the pacing strategies adopted by the rowers in the 2 successive 6-minute rowing tests were remarkably similar,and the rowers'PO and iEMG activities in the two tests were highly correlated,especially in the last minute of exercise.Conclusion It is concluded that the hypothesis of pacing strategy is controlled by CNS.