No abstract

This study has shown that Cdiet is the best approach to standardise dietary intake, especially when the expected effect of an intervention is small and an enhanced reliability is required.

Discrepancies in energy and macronutrient intakes between tests are apparent even when a solid prepackaged diet (Sdiet) is used to standardize dietary intake for preexperimental trials. It is unknown whether a liquid prepackaged diet (Ldiet) leads to improved adherence, resulting in lower variability in energy and macronutrient intakes. This study assesses the ability of athletes to replicate a diet when an Ldiet or Sdiet was used as a dietary standardization technique. In a cross-over design, 30 athletes were randomly assigned to either Sdiet or Ldiet. Each diet was consumed for two nonconsecutive days. Participants were instructed to consume all the meals provided and to return any leftovers. The coefficient of variation (CV) was calculated for each nutrient for the two methods and reported as the average CV. The Bland–Altman plots show that differences between Days 1 and 2 in energy and macronutrient intakes for both diets were close to zero, with the exception of some outliers. The %CV for Sdiet was higher than Ldiet (5% and 3% for energy, 5% and 3% for carbohydrate, 5% and 2% for protein, and 5% and 3% for fat, respectively). There was a strong positive correlation for energy and all macronutrients between Days 1 and 2 for both methods (r > .80; p < .05). Ldiet is an effective technique to standardize diet preexperimental trials and could be used as an alternative to Sdiet. Furthermore, Ldiet may lead to additional improvements in the compliance of participants to the diet and also decrease the cost and time of preparation.

Rowing is an endurance sport with an important skill component. This study evaluated the effects of carbohydrate (CHO) solution ingestion on rowing technique before and after 60 min of ergometer rowing. On two occasions, eight male rowers (age 22±2 years, height 182±4 cm, weight 72.9±2.1 kg, VO2max 4.9±0.2 litre/min) rowed as a group in an indoor rowing tank for 6 min at 18 strokes per minute before and after 60 min of ergometer rowing at 60% of VO2max. Participants ingested either a 6% CHO solution or a flavoured placebo (PLA) in a randomised, counterbalanced fashion. Physiological and technical measures were analysed using a repeated measures analysis of variance. Oar handle curves were analysed using Geometric Morphometrics (principal component analysis). There were no differences in heart rate or rating of perceived exertion between the treatments, indicating similar physiological strain. There were no changes in stroke length over the 60-min period with either treatment. Oar handle velocity decreased from 49.7±3.6 to 47.4±2.8°/s (p<0.05) over the 60-min period in PLA but did not change in CHO (48.9±2.2-48.2±1.9°/s). Oar handle curves did not differ between CHO and PLA (procrustes distance=0.645). Maximum blade depth declined similarly by 20±16% in both CHO and PLA (p<0.01). This change is likely to decrease the resistance of the water upon the oar blade during the drive phase of the rowing stroke. In conclusion, selected measures of rowing tank technique deteriorated in response to 60 min of ergometer rowing in both PLA and CHO. Ingestion of CHO may help to maintain velocity of movement as rowers fatigue. Future research should investigate technique during on-water rowing to evaluate the effects of fatigue and CHO ingestion on rowing technique in the natural competitive environment.