Abstract
Competitive oarsmen (n=8) and oarswomen (n=9) completed three on-water 1800 m time-trials, each separated by 48 h, under cool conditions (8.4 ± 2.0 0C, 50.0 ± 10.2 % humidity). No weight limit was imposed for the first time-trial. However, one of the remaining two trials was undertaken following 4% body weight loss (WT-4%) in the previous 24 h, the sequence of trials randomised between athletes. Aggressive nutritional recovery strategies were enforced in the 2 h following WT-4%. A linear mixed-effects model was used to analyse data with time-trial time, sex, weight and trial order as fixed effects, and subject as a random effect. The effect of sex was highly significant (mean 45.0, 95% CI 36.1 – 53.8 sec; P<0.01), with little evidence of interaction between sex and other fixed effects (P>0.05). WT-4% had only a small and statistically non-significant effect on on-water time-trial performance (mean 1.0, 95% CI -0.9 – 2.8 sec; P = 0.29) compared with unrestricted trials. Similar to time-trials undertaken on the rowing ergometer[1], optimisation of nutrient intake in recovery following weigh-in minimises the impact of acute weight loss (4%) upon on-water rowing performance. However, the performance of these same athletes on ergometer trials undertaken in thermally stressful conditions remained significantly compromised[1]. The discrepancy in the degree of impact of WT-4% on ergometer versus on-water trials may be a consequence of several factors: 1) on-water performance may be limited by the need to retain biomechanical efficiency, maintaining exertion below a threshold at which cardiovascular and/or thermoregulatory functions are compromised, and/or 2) overall cardiovascular strain is lower when exercising in cool conditions and is thus less likely to be challenged sufficiently to compromise rowing performance, even in the presence of hypohydration. Podium Presentation.