| Effects of Different Surface Coefficient of Restitution and Drop Height on Vertical Ground Reaction Force, Joint Angular Velocity, Moment and Muscle Activity during Drop Landing |
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Jin-Seok Lee, Chang-Gyun Kim, Sung-Jin Yoon |
Korea University
Gachon university |
Correspondence:
Sung-Jin Yoon,
Email: jiss@korea.ac.kr
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Received: 23 January 2013 • Accepted: 20 April 2013 |
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| Abstract |
INTRODUCTION
The purpose of this study was to investigate the effects of different surface coefficient of restitution(SCR) and drop height on ground reaction force, joint angular velocity, moment, and muscle activity during drop landing.
METHOD
The subjects were 8 university students majoring physical education performed landing exercises for four weeks. The participants performed 30cm and 60cm height drop landing on three different surface with randomized control and cross-over design. Thee-dimensional motion analysis, surface EMG, and force plates were used to measure ground reaction force, joint angular velocity, and muscle activity of lower limb. The datas were statically analyzed by two-way ANOVA with repeated measures and Bonferroni’s post-hoc test. All significance level for the analysis was set at .05.
RESULTS
At 60cm, the maximum vertical ground reaction force was high with SCR. The angular velocity of ankle joint was the result from 60cm was higher than that from 30 cm on every field. In landing from 60cm, the knee extension moment was high with SCR. Also the ankle and knee extension moments was that the result from 60cm was higher than that from 30cm on every field. In landing from 60cm, the muscle activity of rectus femoris, medial and lateral gastrocnemius was the result from floor was higher than that from natural grass and a mat. In landing from 60cm and 30cm, the muscle activity of tibialis anterior was the result from floor and natural grass was higher than that from a mat, respectively.
CONCLUSION
On this study we leaned that surface of the coefficient of restitution is higher affects loading on body during landing in height of some level, but a low drop height does not affect loading on body with the SCR. Therefore, our study suggest that In landing from 30cm drop heigh, the initial rehabilitation program based on the box or training during off season can provide a safe drop. |
| Keywords:
Landing, Surface coefficient of restitution, Vertical ground reaction force, Joint angular velocity, Moment, Muscle activity |
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