A study was carried out to investigate the application and method of adjusting a cant, and its effect in ski boots. Forty-two professional ski instructors were asked by questionnaire about the application and method of adjusting a cant, and its effect, etc. Simultaneously they were also checked regarding the alignment of the lower extremities. In order to reveal the effect of cant quantitatively, an experiment was performed on a ski-slope. The inclination of the axis of the lower leg was measured at an angulation position on the slope after placing a 1-mm, 3-mm, or 5-mm thick plastic medial wedge between the boot and the ski, so as to give valgus inclination to the heel.
The results and conclusions are summarized as follows ;
1) Twenty-seven of the forty-two subjects used a cant, and about one third of them stated that its effect was unknown.
2) Valgus cant ( (+) cant) had the effect of improving edge-control and decreasing the inclination of the lower leg, whereas varus cant ( (-) cant) had the effect of smoothing the sliding of the ski tail in the latter half of a turn.
3) There was little change in the axial inclination of the lower leg, even when a 5-mm-thick plastic medial wedge was placed between the boot and the ski.
4) A cant compensates not for static malalignment of the lower extremities but for deficiency of joint movement, and should be adjusted according to a skier's individual technical problem, for example poor edge-control, utilizing its merits described in 2) .

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.

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.

Anterior Cruciate Ligament Injury often occurs as a result of knee valgus collapse during landing or pivoting in sports activity. Previous studies reported that the risk of ACL injuries was reduced by jump and balance training, and those training can be effective as the prevention program for the ACL injuries. But those studies often focused on only adult athletes, and there are few studies focused on junior athletes. The purpose of this study is to investigate the pattern of landing movement in junior athletes, and to verify the effect of the prevention program. One-hundred and ten junior basketball players (boys; 61, girls;49, age ranging 12 to 15) were subjected in this study. We measured the knee flexion, valgus angles and jump height during continuous vertical jump. After measuring, they executed a prevention program for 12 weeks. The motion pattern of the knee during jump test were compaired between before and after prevention program. Female athletes showed greater knee valgus angle at initial landing phase and grater maximum knee valgus angle than those of males. As a result of the prevention program, maximum knee valgus angle was significantly decreased in female athletes. The greater angle of knee valgus in female may increase the risk of ACL injuries. Present study suggests that the prevention program is useful for reducing the risk of ACL injury. Increment of jump height in male players after this program might be considered that this training program has also an effect of performance improvement.