Reid Reale, Gregory R Cox, Gary Slater, Louise M Burke

We examined the relationship between the re-gain of body mass (BM) after weigh-in and success in real-life judo competition. Eighty-six (36♀/50♂) senior judoka volunteered for this observational study of an international judo competition. Subjects were weighed at the official weigh-in and one hour before their first competition fight (15-20 hours later). Regain in BM after weigh-in was compared between medal winners and non-medallists, winners and losers of each fight, males and females and across weight divisions. Heavyweights were excluded from analysis. Pre-fight BM was greater than BM at official weigh-in for both males and females, with % BM gains of 2.3±2.0 (p=<0.0001; ES= 1.59; CI95% [1.63, 2.98]) and 3.1±2.2 (p=<0.0001; ES=2.03; CI95% [2.30, 3.89]), respectively. No significant differences were found between weight divisions for post weigh-in BM re-gain. Differences in post weigh-in BM re-gain were significantly higher in medal winners than non-medallists for males and females combined (1.4±0.4% BM; p=0.0026; ES= 0.69; CI95% [0.05, 2.34]) and for males alone (1.5±0.6% BM; p=0.017; ES= 0.74; CI95% [0.02, 2.64]), but not for females (1.2±0.7% BM; p=0.096; ES=0.58; CI95% [-0.02, 2.31]). Differences in BM re-gain after weigh-in between winners and losers were significant across all fights (0.9±0.3% BM; p=0.0021; ES= 0.43; CI95% [0.31, 1.41]) but not for first round fights (0.8±0.5% BM; p=0.1386, ES=0.38; CI95% [-0.26, 1.86]). Winners showed a greater re-gain in BM post weigh-in than losers. This may reflect the greater magnitude of the BM loss needed to achieve weigh-in targets which also relates to the experience level of successful athletes.