Background: This study aimed to investigate the effect of 5% rapid weight loss on hydration status and judo performance in highly trained judo athletes. Methods: Eighteen male judo athletes participated in the study and were divided into two groups: control and rapid weight loss (RWL). RWL athletes were given 48 h to cut 5% of their body mass while the control group followed their routines. Athletes performed three measurements, including hydration, body mass and three consecutive special judo fitness tests (SJFTs). At the 1st and 6th minutes following each SJFT and 1st, 6th and 15th minutes following the last SJFT, blood lactate and heart rate (HR) was monitored. Results: The effect of RWL on variables was tested with split-plot ANOVA. RWL significantly affected urine specific gravity with a higher value following weight loss compared to baseline and recovery (F2-32 = 13.2, p < 0.001). In addition, athletes’ SJFT total throw numbers differed among measurements (F2-32 = 7.70, p < 0.001). Athletes presented worse SJFT index after weight loss (F2-32 = 8.05, p = 0.01; F1-16 = 6.43, p = 0.02, respectively). HR changed significantly among measurements days and times (F28-448 = 143.10, p < 0.001). Conclusion: RWL induced dehydration and impaired heart rate recovery in highly trained judo athletes, and they could not rehydrate between competition simulated weigh-in and 15 h of recovery.

Background: The present study investigated highly trained male judo athletes and how a 5% body mass dehydration affects their judo-specific performance and physiological responses. Methods: Nine highly trained international-level male judo athletes who are weight-cyclers voluntarily participated in the study. The study had a controlled crossover design in nature. Athletes completed three sessions, including a familiarisation session and two experimental sessions (dehydration (DEHY) and control (CON)) with judo-specific tests, including maximal handgrip strength test (HGS), judogi grip strength tests (JGST), and the Special Judo Fitness Test (SJFT). Results: Intergroup analysis revealed a significant increase in urine specific gravity (USG) and decreased body mass following DEHY condition compared to CON. Furthermore, significant decreases were determined in HGS, JGSTs, and a number of throws in the first and third series of SJFTs, as well as higher heart rate (HR) responses in the second and third series of SJFT and worse SJFT index in DEHY condition (p < 0.05). Conclusions: We concluded that 5% dehydration of body mass led to impairment in dynamic and isometric strength in upper limbs and in judo-specific performance, as well as elevated HR during the SJFT.

The effects of penalties on match outcomes were investigated in this study. Data were obtained from a total of 5039 matches that included men, women, and all weight categories during the latest two world championships and eight different grand prix tournaments. The effects of shido on losing and factors affecting these penalties were determined with a binary logistic regression analysis. Receiving a shido during the match increased the possibility of losing (Odds ratio (OR)= 1.14). The possibility of defeat of the athletes who received the second shido was higher compared to those who did not (OR= 2.13). The possibility of penalisation with both first shido (OR= 1.86) and second shido (OR= 2.76) of defeated athletes was higher than winners. Each 1-minute increase in match duration increased possibility of receiving a shido (OR= 2.10, for first shido; OR= 1.87 for second shido). Despite current rule changes that aimed to decrease direct effects of penalties on match outcomes to create positive judo, receiving a shido was found to still significantly affect competitors’ techniques and tactics during the match and indirectly affect the match outcomes. Therefore, it is suggested that coaches and especially heavyweight athletes should evaluate the effects of shido on match tactics.

This study aimed to investigate the effect of weigh-in time on hydration status and acute weight gain (AWG). Twenty-seven men judo athletes and 23 men wrestlers voluntarily participated in this study. Body mass and urine specific gravity (USG) of the athletes were measured just before official weigh-in and competition. Two-way analysis of variance (split-plot ANOVA) with repeated measurements (time x sport) were used to determine differences in AWG and USG between groups and measurement times. In case of significant difference between sports, t-tests were applied. There was a significant main effect of time (p<0.01, ES=0.25) on USG. A significant difference was found in USG between official weigh-in and start of the competition in wrestlers (p<0.01) but not in judo athletes. There was significant difference in AWG and AWG% between sports (p<0.01). Moreover, most of the athletes presented high level of dehydration before both official weigh-in and competition. In conclusion, judo athletes could not rehydrate as much as wrestlers despite 15h of recovery. It can be suggested that the period between official weigh-in and competition would be shortened to prevent non-optimal hydration status and rapid weight gain, with caution to allow sufficient recovery period.

The normative values of the Special Judo Fitness Test (SJFT) are used to evaluate judo athletes, and the question arises of which performance tests from crucial motor abilities best define the SJFT classification in elite judo athletes. This study aimed to investigate the relationship between elite judo athletes’ physical performance and the evaluation using SJFT index norms. Nineteen judo athletes (11 females) (22.8 ± 2.5 years old) from the senior judo national team voluntarily participated in this study. Body composition, reaction time, balance, flexibility, agility, hand grip strength, 20 m sprint, vertical jump, SJFT, and Wingate tests were performed by athletes on four separate days at one-day intervals. Athletes were classified as regular and above (≥regular) or poor and below (≤poor) according to their SJFT index scores. Simple logistic regression analysis was used to evaluate this classification’s consistency with performance test results. Odds ratios (OR) and 95% confidence intervals related to each possible factor and Wald test statistics were calculated. The SJFT index classification was associated with Wingate peak and mean power, vertical jump, and sprint performance results (p < 0.05), whereas it was not associated with body fat percentage, agility, reaction time, hand grip strength, flexibility, and balance performances (p > 0.05). SJFT index classificatory norms are mainly related to athletes’ anaerobic power. Higher anaerobic power increases athletes’ possibility of being classified as ≥regular.

The International Judo Federation (IJF) implemented new regulations in an attempt to regulate rapid weight loss in 2013. The body weight of the athletes cannot be more than 5% higher than the upper...