Relationship Between Low Back Pain and Trunk Muscle Strength in University Judo Players

Abstract

1403 A high incidence of low back pain (LBP) has been reported among judo players. At the 50th Annual Meeting of ACSM, our group reported that wrestlers with high disability level of LBP showed lower trunk extensor strength. Same tendency is also expected to exist in judo players. PURPOSE: This study was to examine the characteristic of trunk muscle strength in university judo players with LBP. We especially focused on weight classes. METHODS: Subjects were 66 male university judo players. In this study, we classified judo players into three weight classes as follows; the lightweight class (−60, −66kg, N = 14), the middleweight class (−73, −81kg, N = 29), and the heavyweight class (−90, −100, +100kg, N = 23). Peak torques of trunk extensor (PTEX), flexor (PTFX), left rotator (PTLR), right rotator (PTRR) were measured at three different angular velocities (60, 90, 120deg/sec). The extensor/flexor (EX/FX) and left/right rotator (LR/RR) ratios were also calculated. The presence and level of LBP were evaluated using the questionnaire test developed by Osaka City University (the OCU test). Based on this test, we defined the LBP and the non-LBP groups. The level of LBP was evaluated according to the OCU test score (range 0–20). From the obtained results, we examined the following two points; 1) comparison of trunk muscle strength between the non-LBP and the LBP group and 2) correlation between the level of LBP and trunk muscle strength. Student's t-test and Spearman's rank test were used for statistical evaluation. Significance was accepted at the 5% level. RESULTS: In the heavyweight class, the LBP group (N = 9) showed significantly lower PTEX (60deg/sec; P<0.05) and PTRR (60deg/sec; P<0.01) than the non-LBP group (N = 14), but the same tendencies were not observed in the lightweight and middleweight classes. Significant negative correlations between the OCU test score and the PTEX (60deg/sec; r = −0.423, P<0.05), the PTRR (60deg/sec; r = −0.548, P<0.01) were also observed only in the heavyweight class. CONCLUSIONS: University judo players with low back pain show a weakness of trunk muscle strength compared with that in judo players without low back pain in the heavyweight class. The relatively high load on the lumbar region caused by heavy body weight is the probable cause, similar to the situation seen in university wrestlers.