The purpose of this study was to investigate the relationship among torque, motion of lower limbs during the take-off phase and muscle strength of lower limbs. Subjects were 12 male track and field athletes who had a top record of 6.84±0.41 m. Several variables of the 12 subjects, such as displacement, velocity, angle and angular velocity, and maximum torque of the knee and hip joints during the take-off phase, were obtained from film analysis and measurement of lower limb strength by Biodex.
The main results were as follows:
1. Subjects who had a lower angular velocity of the take-off knee joint after landing showed a lower decreasing ratio of velocity during the takeoff phase.
2. There was a significant relationship between records for the long jump and hip flexion torque of the take-off leg during the last part of the take-off phase (r=-0.678, P<0.05) .
3. Subjects who showed a higher value of hip flexion torque of their free leg during the last part of the take-off phase showed lower take-off angles.
4. There was a significant relationship between knee extension strengths (60, 180, 300 deg/s) and knee joint angles at the middle of the take-off phase (r=0.700 P<0.01, r=0.672 P<0.05, r=0.751 P<0.01) .
5. Subjects who maintained a larger knee angle for their take-off leg indicated a decrease in knee extension torque of their take-off leg during the last part of the take-off phase.
6. Subjects who showed higher hip extension strength made the transition to hip flexion torque of the take-off leg from the middle to the last part of the take-off phase.
From these results, it can be seen that knee extension strength is important for efficient take-off, and hip joint torque is one of the factors that influences one's record in the long jump.

Osteoid osteoma (OO) is a benign osteoblastic tumor. Its curative treatment is complete removal of the nidus, where intraoperative localization of the nidus governs clinical results. However, treatment can be difficult since the lesion is often invisible over the bony surface. Accordingly, establishment of an ideal less invasive surgical strategy for spinal OO remains yet unsettled. We illustrate the efficacy of a computed tomography (CT)-based navigation system in excising OO located adjacent to the facet joint of spine. In our 2 cases, complete and pin-point removal of the nidus located close to the facet joint was successfully achieved, without excessive removal of the bone potentially leading to spinal instability and possible damage of nearby neurovascular structures. We advocate a less invasive approach to spinal OO, particularly in an environment with an available CT-based navigation system.
Osteoblasts ; Osteoma, Osteoid* ; Spine* ; Zygapophyseal Joint*