Author(s): CONCEIÇÃO-SANTOS, D., MURASAKI, J., DETANICO, D., ALBUQUERQUE, M., REGISTRO, L., KONS, R., TAKITO, M., FRANCHINI, E., Institution: UNIVERSITY OF SÃO PAULO, Country: BRAZIL, Abstract-ID: 629

INTRODUCTION:
Rapid weight loss (RWL) is widely used in judo under the assumption that competing against lighter opponents enhances performance [1]. Under current competition rules, athletes may weigh up to 5% above the upper limit of his/her weight category, potentially influencing hydration status and psychophysiological demands [2]. Thus, this study examined the effects of RWL magnitude on hydration, cardiac autonomic regulation, cognitive performance and competitive outcomes in elite judo athletes.
METHODS:
Thirty-seven nationally and internationally competitive judo athletes (27 males and 10 females; 20.3±2.1 years) were monitored during official competitions. Body mass was assessed at 10, 7 and 3 days before weigh-in, at official weigh-in, and on competition day. Athletes were classified according to RWL magnitude (<5%, n= 21; >5%, n= 16). Urinary osmolality, body water compartments, heart rate variability, cognitive performance and perceived self-control demands were assessed longitudinally. Competitive success was defined by match outcomes and medal attainment, while technical-tactical variables included scoring indices, technical variability and time motion analysis. Data were analyzed using analysis of variance and non-parametric tests when appropriate. Relationships were examined using Spearman correlation. Statistical significance was set at 5%.
RESULTS:
Body mass decreased progressively from -10 days to weigh-in and rebounded on competition day (p<0.001). Urinary osmolality increased significantly across the pre-competition period, with a median increase exceeding 250 mOsm/kg from -10 days to weigh-in (p<0.001). Athletes reducing >5% body mass showed greater osmolality deltas than those reducing <5% from -10 days to weigh-in (433 vs 166 mOsm/kg; p=0.001) and from -10 days to competition (207 vs 87 mOsm/kg; p=0.043). Heart rate variability indices, body water compartments and cognitive performance changed over time but did not differ between groups (p range = 0.06–0.90). No differences were observed between groups for winning probability (65±20% vs 70±26%), medal attainment, scoring efficiency (33±18% vs 28±23%) or time-motion, including total combat time (152±67s vs 148±71s) and effort-to-pause ratio (1.6± 0.5 vs 1.5±0.5). However, athletes reducing <5% body mass demonstrated greater technical variability than those reducing >5% (37±17% vs 26±15%, p=0.032). Finally, urinary osmolality at weigh-in was positively associated with perceived self-control demands measured at -10 days (r=0.52, p<0.001), -7 days (r=0.49, p=0.002) and -3 days (r=0.39, p=0.015).
CONCLUSION:
Under current judo competition rules, increasing the magnitude of RWL does not seem to increase competitive success, but increases cognitive and psychophysiological demands.

Funding: FAPESP – 2024/18847-4 and 2024/08930-1; CNPq – 403032/2023-7, and 305507/2023-0.
[1] Dos Santos et al. (2024) Phys Act Nutr. 28(3).
[2] Ceylan et al. (2022) Biology 11(6).