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.