The Effect of Ad Libitum Carbohydrate-Electrolyte or Placebo Solution Intake on Fluid Balance and Soccer Skill Performance of Preadolescent Boys in Warm Environment

This study compared the effect of a carbohydrate-electrolyte or placebo solution on fluid balance and soccer skill performance of preadolescent boys exercising in warm environment. Sixteen soccer academy club players aged 10.4 ± 0.1 years (Tanner stage: 2.1 ± 0.1) performed two identical 60 min training sessions at about 29°C and relative humidity 38-43% while ingesting ad libitum and randomly either a 6% carbohydrate-electrolyte solution (CHO-E) or an artificially sweetened placebo (P). After the completion of the training, participants performed five soccer skill tests (SST). The SST had also been performed in a previous occasion when children had undergone only a 10-min warm-up (BestP). Body mass (BM) was maintained after training in both conditions, whereas BM loss, estimated sweat loss, percentage of BM loss, heart rate, perceived rate of exertion, abdominal discomfort and thirst were not different between trials. Fluid intake was higher in CHO-E (642 ± 50 ml, range: 300-985 ml) compared to P (458 ± 56 ml, range: 80-1010 ml) (p=0.017). Performance in SST was not deteriorated as a result of the training and was not different between BestP, CHO-E and P. Fluid intake was not correlated with sweat loss (r=0.14). It is concluded that, when exercising for 60 min in warm conditions and have access to fluid, children maintain their fluid balance and soccer skill performance equally well by ingesting either a CHO-E solution or an artificially sweetened placebo.