BIOMECHANICS OF TEACHING FOR H I P PULLOVER EXERCISE IN PHYSICAL EDUCATION CLASS

Abstract

The purpose of this study arc l ) to make the special apparatus for hippullover exercise in physical education - 2 ) to assess the effect of instruction using special apparatus. The special apparatus called SAKA-AGARI Unit(in Japanese).consist of three condition for practice-circular arch, trampoline and board, rcspective1y.Children who have few experience of inverse position and scared of horizontal bar exercise can easily practice in this apparatus. SAKA-AGARI Unit. which is different from traditional supporting apparatus, has strain gages attached to the bar. Using this attachment, it is possible to quantitate the force exerted to the bar both horizontal and vertical direction electrically. Eight elementary children were tested through the physical education class using SAKA- 1 AGARI Unit, 20min. in a day, 3times/week , for 2 weeks. EMG .kinetic and kinematic data were obtained during hip pullover exercise pre during and post class. EMG of the non-acquired children changed, especially latissimus dorsi and rectus abdominals muscle activities were more effective through physical education class. Abut the kinetic data, exerted force on the bar in vertical condition increased significantly through class (p<0.05, 0.96, 0.74, 1.32 kg/w, respectively). Moreover, ground reaction force in vertical direction also increased significantly(p<0.05. 1.27, 230. 2.37kg/w). As for the kinematic data, focus of C.G. moved directly to the bar. And also , the knee velocity of up-swinging leg increased through class from 3.4m/sec to 4.0m/sec. About the effectiveness and efficiency of instruction, the value of accomplishment rate for the non acquired was 75.0%, significantly higher than the traditional technique (p<0.05) and the average days for acquiring hip pull over skill were 3.6 days, shorter than previous studies. To obtain the more practical data, the instruction using SAKA-AGARI Unit for longer period was given to the children who were obese and scared of the inverse position. As a result, children with disadvantages such as obesity and mental uneasiness can not easily acquire the skill of hip pullover, but the improvement for hip pullover movement was observed through instruction. In SAKA-AGARI unit, exerted force on the bar in circular arch condition was half as much as board condition. The increase of knee-velocity for up-swinging leg may depend on the elasticity of trampoline bed. It is suggested that the SAKA-AGARI Unit was the effective apparatus for decreasing gravitational force and makes elementary children practice with much fun during hip pullover exercise.