The use of water-loading to enhance weight cutting is getting increasingly popular in combat and weight category sports. Athletes are overdrinking water in order to increase urine production before engaging in a fluid restriction period in the belief that it will maximise fluid driven body mass loss. Research into this practice is lacking and further investigation is needed.
PURPOSE: Determine the impact of a water-loading protocol in combination with dietary adjustments on acute body mass loss, natremia, urinary markers of hydration and arm crank performance in elite judo athletes.
METHODS: Using a crossover design, 18 elite male judo athletes underwent 2, 6 days interventions interspersed by a washout period of 2 weeks. While following a controlled diet, athletes consumed either 40 mL/kg (control condition (CON)) or 80 mL/kg (water loading condition (WL)) on days 1-3, followed for both conditions by a fluid intake of 20 mL/kg on day 4. On day 5, fluid was restricted until 11h00, body mass was then measured and for the remaining of the day athletes consumed 60 mL/kg of fluid. On day 6, fluid was consumed ad libitum and arm crank performance measured between 9h00-12h00.
RESULTS: Water-loading (2.4 ± 0.5%) produced a significantly (p = 0.03, effect size = 0.7) greater decrease in body mass, compared with CON (1.8 ± 0.5%). Urine specific gravity and osmolality became progressively lower over time with WL (p < 0.05), compared with CON. However, whole blood sodium concentration remained within the physiological range of 135-145 mmol/L throughout the WL condition. There were no significant differences in arm crank performance for maximum power (CON: 663 ± 103, WL: 677 ± 95 W) and mean power (CON: 330 ± 32, WL: 335 ± 35 W).
CONCLUSION: Our results indicate that the water-loading protocol used in this study 1) improves acute body mass loss without affecting health or arm crank performance and; 2) should be considered by combat sports athletes looking to improve their weight cutting practices.
Funding information :
1) Own the Podium i4G applied research program 2) INS Quebec PRIDI research grant