Rapid pre-match weight loss for judo athletes may not lead to poor performance, but dehydration cannot be compensated for 15 hours after weight loss and may affect health and performance in the long run. The results were reported. The authors state that precautions should be taken to avoid rapid weight loss.
The benefits of rapid weight loss (RWL) are still unclear
Athletes in weight-class sports, including judo, often pass the weighing by performing rapid weight loss (RWL) before the match in order to face the match under favorable conditions. In the case of judoka, there are reports that 60-80% use this strategy.
Some studies have shown that such a strategy is positive for match results, but some studies deny it, and the results are inconsistent. In addition, some studies have shown that repeated rapid weight loss (RWL) hinders performance improvement, but some studies deny it, and the results are inconsistent in that respect as well.
Against this background, the authors of this paper examined the performance and dehydration risk of judo athletes due to rapid weight loss (RWL).
Tested under conditions in line with the regulations of the International Judo Federation (IJF)
The research target is 18 elite male judo players. The eligibility conditions were that he had more than 5 years of judo experience and was at the first grade or higher, that he had participated in international competitions, and that he had not been injured in the musculoskeletal system the previous year.
The subjects were divided into two groups of 9 patients, one group was used for rapid weight loss (RWL), and the other group was used as a control group without weight loss. Athletes assigned to the RWL group have performed more than 5 RWLs per year for the past 3 years.
Research protocol and performance evaluation method
In this study, a total of three measurements were performed: weighing, urine / blood sampling, heart rate measurement, and performance test.
First, the first series of these tests was conducted at 19:00. Athletes assigned to the RWL group were then required to lose 5% within 48 hours. The use of laxatives and diuretics was banned when reducing weight.
At 19:00 (official measurement time of the International Judo Federation (IJF)), two days after 48 hours, the second measurement, urine collection / blood collection, performance test, etc. were conducted. After that, the third measurement was performed the day after the recovery period of 15 hours. Weight gain during the recovery period in the RWL group should not exceed 5% from the time of weighing in accordance with the IJF regulations.
The performance test was evaluated by the “Special Judo Fitness Test; SJFT”, which is an evaluation index peculiar to judo. The throwing technique “Tori” and the thrown “Uke” are combined from a position 6m apart, and the subject becomes “Tori”, and the number of throwing techniques is counted as many times as possible within 30 seconds. Repeat it 3 times, with a 10-minute break in each trial. Blood sampling and heart rate measurements were performed 1 and 6 minutes after each trial, and the final SJFT measured them 15 minutes later.
Verification of the long-term effects of repeated rapid weight loss is required
Let’s see the result.
First, about the performance evaluated by SJFT.
Performance at weighing time is poor in the RWL group, although differences between groups are not significant
When the number of SJFT throwing techniques performed 3 times per opportunity, 9 times in total, was totaled for each opportunity, the control group did not change significantly over time. On the other hand, in the RWL group that underwent rapid weight loss, the number of throwing techniques immediately after weight loss was small, and there was a significant difference from the number of throwing techniques after recovery.
However, when comparing the control group and the RWL group, no significant difference was observed at all measurement points.
Dehydrated after 15 hours of recovery in the RWL group
Next, the urine specific gravity was 1.019 ± 0.006 g / mL in the control group and 1.014 ± 0.005 g / mL in the RWL group in the first measurement, and the mean value was not at the dehydration level in both groups. However, at the time of weighing 48 hours later, the RWL group was dehydrated (more than 1.020 g / mL) at 1.026 ± 0.003 g / mL, and after another 15 hours of recovery, it was 1.022 ± 0.005 g / mL. , The average value was at the dehydration level. On the other hand, in the control group, the average value was 1.020 g / mL or less at all measurement points.
Heart rate after SJFT is also significantly different
There was also a significant difference in heart rate. Specifically, the RWL group had a larger fluctuation range in heart rate at each measurement point than the control group, and the heart rate one minute after the second and third SJFTs was significantly higher.
There were no significant differences in lactate levels.
In conclusion, “In this study, rapid weight loss did not affect judo-specific performance, but partially increased physiological load during exercise, and weight gain of up to 5% with a 15-hour recovery. It should be noted that despite the increase, sufficient dehydration could not be corrected. Future studies will need to focus on the long-term effects of dehydration due to repeated rapid weight loss. ” Has been done.
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【 Sports Nutrition Web Editorial Department 】