The purpose of this study was to investigate the relationship between low back pain (LBP) any physical characteristics in university wrestlers. We especially focused on radiological abnormalitie (RA) in their lumbar regions.
Physical characteristics and isokinetic trunk muscle strength of the 55 male university wrestlers were measured. MRI was used to evaluate the cross-sectional areas of trunk muscles between lumbar spine 3 and 4 (L3/4) . Evaluations of LBP were based on the diagnose of orthopedic surgeons and the questionnaire test. According to this evaluation, we assigned all wrestlers into two groups as the LOP group and the no LOP group. Furthermore, four groups were defined by having RA based on X-ray and MRI diagnose.
We obtained the following results. In comparison between the LOP group and the no LOP group, the trunk muscle extension flexion strength ratio of the LOP was significantly lower than that of the no LOP group. In addition, the LOP without RA group showed significant low strength of their trunk extensors in comparison with the no LOP without RA group.
We considered that the relative low strength of trunk extensors should have some effect on LBP in university wrestlers.

The purpose of this study was to investigate relationships between low back pain (LBP) and psychological conditions in university wrestlers.
We examined psychological conditions of seventy male university wrestlers using the Psycholo gical Condition Inventory (PCI) test and evaluated whether psychological conditions have some relationships with LBP. Evaluations of LBP were based on a questionnaire test and the diagnosis of orthopedic surgeons. Based on the LBP evaluation, we assigned all wrestlers into two groups as the LBP group and the non-LBP group.
We obtained the following results. There were twenty-eight university wrestlers (40%) in the LBP group and forty-two wrestlers (60%) in the non-LBP group. Wrestlers in the LBP group showed significantly high values in all factors relating to fatigue in comparison to the non-LBP group.
We conclud that the university wrestlers with LBP feel fatigue in their minds and bodies.

It is thought that for some sports so called the “agility” accomplishes the key role from the viewpoint of the improvement of the performance and the injury prevention. Therefore we examined the influence of bite up with the oral appliances on the agility.Tested sporting event were cervical retroflexed force. EVA mouthguard and resin splint were used for the oral appliances. Reaction time was measured as a response to stimulated light by the activating time of the masseter muscle and activating time of the main muscle.It is found the reaction time of neck muscles movement tends to be shortened by wearing of the oral appliances.These results were seemed to be based on decrease of a free way space by the bite up with the oral appliances resulted in shortening the reaction time of the masseter and the stabilized occlusion.(141 words)

To investigate the relationship between adolescent sport activity and abnormalities of the lumbar spine on radiography and magnetic resonance imaging (MRI), 237 collegiate athletes (mean age 19.4), representing judo, wrestling, and track, were analyzed from the point of contact or noncontact sports. Radiologic and/or MRI abnormalities of the lumbar spine were found in 68.7% of contact sports athletes (judo and wrestling, n=147), 53.3% of noncontact sports athletes (track, n=90), 69.9% of athletes who have played contact sports over 9 years (C9 athletes, n=83), and 47.1% of atheletes who have done noncontact sports over 9 years (N9 athletes, n=17). Discopathy related abnormalities on radiologic examination were found in 25.3% and 11.8% of C9 and N9 athletes. Disc degeneration on MRI was found in 45.8% and 29.4% of C9 and N9 athletes. Spondylolysis was found in 31.3% of C9, 5.9% of N9, 31.3% of elementary-C (athletes who played contact sports during elementary school, n=96), 32.8% of elementary-L/I (limited contact/impact sports, n=58), and 8.6% of elementary-N athletes (noncontact sports, n=35), respectively. From these results, we concluded that contact sports activity during adolescence induces lumbar spine abnormalities at a higher rate compared to noncontact sports and that spondylolysis is related to contact or limited contact/impact sport activity during elementary school.

The purpose of this study was to clarify physical characteristics related to low back pain (LBP) in collegiate track and field athletes. We particularly focused on the nature of the track and field. The subjects were 21 male collegiate track and field athletes including only sprinters, hurdlers, long jumpers and triple jumpers. The examined parameters were physical characteristics, isokinetic flexor and extensor strength in the knee and trunk regions. The evaluation of LBP was estimated by a questionnaire test and orthopedic surgeons' diagnosis. According to these evaluations, we divided all track and field athletes into two groups ; LBP group (n＝11, 52.4%) and no LBP group (n＝10, 47.6%). As a result, a take-off leg of knee flexor/extensor strength ratio in the LBP group was significantly lower than that in the no LBP group (P＜0.05). The LBP group showed a significant difference between a take-off leg and a lead leg in knee flexor strength compared with the no LBP group (P＜0.05). The LBP group has been short engaged in the track and field than the no LBP group (P＜0.05). In the trunk flexor and extensor strength, there was no significant difference between the LBP and the no LBP group in this study. These results suggest that the imbalanced knee muscle strength may be one of some factors related to chronic low back pain in collegiate track and field athletes.