Author(s): ZHOU, F., LIU, Y., Institution: BEIJING RESEARCH INSTITUTE OF SPORTS SCIENCE, Country: CHINA, Abstract-ID: 2540

INTRODUCTION:
To quantify the dynamic changes in the incidence of low energy availability (LEA) in female judo athletes during the pre-competition weight loss period, clarify the impacts of LEA on physiological functions and athletic performance, and construct a risk early warning system.
METHODS:
Subjects were divided into high/low-risk groups according to their energy availability (EA) values 4 weeks before competition. Energy balance, physiological and biochemical indicators, and athletic performance were monitored longitudinally at 4, 2, and 0 weeks before competition. Paired t-test and repeated measures analysis of variance were used to test inter-group and intra-group differences.
RESULTS:
1. The incidence of low energy availability (LEA) increased sharply from 45.5% at 4 weeks before competition to 100% at 0 weeks before competition (P<0.01), and the average EA value decreased significantly (P<0.01); the initial energy intake of the high-risk group was significantly lower than that of the low-risk group at 4 weeks before competition (P<0.05).
2. Impaired metabolic and endocrine functions: Resting metabolic rate (RMR) decreased by 8% before competition; testosterone decreased by 18.2%, and cortisol increased by 10.4%; T3 and FT3 in the high-risk group decreased by 17.3% and 18.2% compared with the initial values at 0 weeks before competition (P<0.05); the basic leptin level of the high-risk group was only 40.5% of that of the low-risk group.
3. Bone health monitoring showed that the total body bone mineral density (BMD) of the high-risk group decreased by 1.5% at 0 weeks before competition compared with the initial value, and the body fat rate of the entire group decreased by 12%.
4. Athletic performance showed contradictory changes: The 1-minute heart rate recovery after the Special Judo Fitness Test (SJFT) accelerated by 22.2 beats per minute, but there was no significant change in the number of movements completed.
CONCLUSION:
The incidence of LEA in female judo athletes during the pre-competition weight loss period is as high as 100%, causing multisystem damage: those with initial energy intake <2000 kcal/day or leptin <300 pg/ml are prone to develop severe LEA. LEA inhibits thyroid function, reduces bone mineral density, disrupts sex hormone balance, and exacerbates exercise-induced fatigue. Hierarchical interventions should be implemented: priority should be given to nutritional support for those with LEA or low leptin levels, extreme dehydration methods should be avoided, and an emergency glucose supplementation plan after weight measurement should be formulated. An early warning system should be established to reduce long-term health risks.