腹直肌疲勞對下肢跳躍表現與著地負荷的影響

Abstract

排球選手在比賽中會有反覆的跳躍著地動作，使下肢承受相當大的負荷。下肢關節疼痛是排球選手常抱怨的運動傷害。從以前的研究得知，核心肌群的穩定在四肢快速移動前扮演極重要的角色。目的：腹直肌疲勞對下蹲跳(CMJ)與扣殺式跳躍(SPJ)的跳躍表現與著地負荷的影響。方法：健康的優秀大專男子排球選手12名。使用三維動作分析系統、測力板與表面肌電收集參與者下蹲跳和扣殺式跳躍時腹直肌與下肢肌群活動的關連性。收集前測資料後，介入腹直肌訓練約10分鐘，並立即收取後測，比較腹直肌疲勞前後的影響。統計使用成對樣本t檢定，顯著水準定為α=.05。結果：腹直肌疲勞後，質心最低位置提高，跳躍最大高度降低。起跳腳踝關節力矩減少，制動腳負荷比率增加。結論：腹直肌疲勞後，選手無法完全下蹲，導致跳躍表現變差；著地時的策略改變，造成制動腳負荷變大。教練可針對選手的核心肌群加強訓練，以增加選手運動表現的穩定度及降低下肢傷害的風險。

Volleyball players have a large number of jumping and landing in a game. It may endure the huge load on the joints of lower extremity. The joint injuries of lower extremity occur most frequently in volleyball players. Based on previous studies, the core muscles was more stable, upper and lower extremity could activate faster. Purpose: To evaluate the changes on lower extremity during jumping and landing in counter-movement jump and spike jump after rectus abdominis fatigue. Methods: 12 male volleyball players in collegiate division I were recruited. 3D motion analysis system, force plates and surface EMG were used to collect the kinematics, kinetics, and muscles activation during jumping and landing in CMJ and SPJ. After CMJ and SPJ test, participants were asked to perform the rectus abdominis traininguntil fatigue. The kinematics, kinetics, and muscles activation in CMJ and SPJ were collected again. The paired sample t-test was used to compare the data before and after training. The significant level was set α=.05. Result: After rectus abdominis fatigued, the COM was higher while squat, and the jumping height was lower. While landing, decrease was found in the ankle moment of jumping leg, and increase of the joint load of breaking leg was noted. Conclusion: The players could not fully squat after rectus abdominis fatigued. It caused the jumping height lower. The load ratio of jumping leg and breaking leg was changed during landing, and caused the load increase of breaking leg. Based on the results from this study, coaches could strengthen the core muscles training for volleyball players to increase stability of performance and reduce the risk of lower extremity injuries.