Abstract：
BACKGROUND: Anterior cruciate ligament injuries are directly related to the control of dynamic knee valgus in the landing of a jump, and this is mainly due to the correct activation and neuromuscular function of the lower-extremity muscles. The aim of the study is to assess the relationship between lower limb muscle activity during a single-legged drop jump and knee frontal plane projection angle (FPPA).
METHODS: A correlation study.
METHODS: Thirty healthy collegiate female athletes were included in the study. Main outcomes measures were peak knee FPPA and muscle activity (% of maximal voluntary isometric contraction). Peak knee FPPA during a single-legged drop jump test was identified using a 2-dimensional motion analysis system. Muscle activity was assessed using a surface electromyograph for gluteus maximus, gluteus medius, biceps femoris, semitendinosus, vastus medialis quadriceps, vastus lateralis quadriceps, medial gastrocnemius, and lateral gastrocnemius. All variables were assessed for both dominant and nondominant limbs. A correlation analysis between peak knee FPPA and muscle activity was performed. Statistical significance was set at P <.05.
RESULTS: A mean peak knee FPPA of 14.52° and 13.38° was identified for dominant and nondominant limb single-legged drop jump test, respectively. Muscle activity (% of maximal voluntary isometric contraction) for muscles assessed ranged from 43.97% to 195.71% during the single-legged drop jump test. The correlation analysis found no significant correlation between any of the muscles assessed and peak knee FPPA during the single-legged drop jump test (Pearson coefficient between -.3 and .1).
CONCLUSIONS: There is no association between muscle activity from the lower limb muscles and the knee FPPA during a single-legged drop jump in female athletes. Thus, different muscle properties should be assessed in order to understand such an important movement as the knee FPPA during a jump.
METHODS: A correlation study.
METHODS: Thirty healthy collegiate female athletes were included in the study. Main outcomes measures were peak knee FPPA and muscle activity (% of maximal voluntary isometric contraction). Peak knee FPPA during a single-legged drop jump test was identified using a 2-dimensional motion analysis system. Muscle activity was assessed using a surface electromyograph for gluteus maximus, gluteus medius, biceps femoris, semitendinosus, vastus medialis quadriceps, vastus lateralis quadriceps, medial gastrocnemius, and lateral gastrocnemius. All variables were assessed for both dominant and nondominant limbs. A correlation analysis between peak knee FPPA and muscle activity was performed. Statistical significance was set at P <.05.
RESULTS: A mean peak knee FPPA of 14.52° and 13.38° was identified for dominant and nondominant limb single-legged drop jump test, respectively. Muscle activity (% of maximal voluntary isometric contraction) for muscles assessed ranged from 43.97% to 195.71% during the single-legged drop jump test. The correlation analysis found no significant correlation between any of the muscles assessed and peak knee FPPA during the single-legged drop jump test (Pearson coefficient between -.3 and .1).
CONCLUSIONS: There is no association between muscle activity from the lower limb muscles and the knee FPPA during a single-legged drop jump in female athletes. Thus, different muscle properties should be assessed in order to understand such an important movement as the knee FPPA during a jump.
摘要：
背景：前交叉韧带损伤与跳台时动态膝关节外翻的控制直接相关，这主要是由于下肢肌肉的正确激活和神经肌肉功能。该研究的目的是评估单腿跳伞时下肢肌肉活动与膝盖额平面投影角（FPPA）之间的关系。
方法：相关性研究。
方法：将30名健康的大学女运动员纳入研究。主要结果指标是膝关节FPPA峰值和肌肉活动（最大自愿性等距收缩的百分比）。使用二维运动分析系统确定了单腿跌落跳跃测试期间的膝盖FPPA峰值。使用臀大肌的表面肌电图评估肌肉活动，臀中肌,股二头肌,半腱肌,股四头肌，股四头肌外侧肌,腓肠肌内侧,和腓肠肌外侧.所有变量均针对优势和非优势肢体进行评估。对膝关节FPPA峰值与肌肉活动进行相关性分析。统计学显著性设定为P<0.05。
结果：对于优势肢体和非优势肢体单腿跌落跳跃试验，确定平均峰值膝关节FPPA为14.52°和13.38°，分别。在单腿跳跳测试中，评估的肌肉的肌肉活动（最大自愿性等距收缩的百分比）范围为43.97％至195.71％。相关性分析发现，在单腿跳伞试验中，评估的任何肌肉与膝关节FPPA峰值之间均无明显相关性（皮尔逊系数在-3和.1之间）。
结论：在女性运动员单腿跳台过程中，下肢肌肉活动与膝关节FPPA之间没有关联。因此，应评估不同的肌肉特性，以了解跳跃过程中膝关节FPPA等重要运动。
方法：相关性研究。
方法：将30名健康的大学女运动员纳入研究。主要结果指标是膝关节FPPA峰值和肌肉活动（最大自愿性等距收缩的百分比）。使用二维运动分析系统确定了单腿跌落跳跃测试期间的膝盖FPPA峰值。使用臀大肌的表面肌电图评估肌肉活动，臀中肌,股二头肌,半腱肌,股四头肌，股四头肌外侧肌,腓肠肌内侧,和腓肠肌外侧.所有变量均针对优势和非优势肢体进行评估。对膝关节FPPA峰值与肌肉活动进行相关性分析。统计学显著性设定为P<0.05。
结果：对于优势肢体和非优势肢体单腿跌落跳跃试验，确定平均峰值膝关节FPPA为14.52°和13.38°，分别。在单腿跳跳测试中，评估的肌肉的肌肉活动（最大自愿性等距收缩的百分比）范围为43.97％至195.71％。相关性分析发现，在单腿跳伞试验中，评估的任何肌肉与膝关节FPPA峰值之间均无明显相关性（皮尔逊系数在-3和.1之间）。
结论：在女性运动员单腿跳台过程中，下肢肌肉活动与膝关节FPPA之间没有关联。因此，应评估不同的肌肉特性，以了解跳跃过程中膝关节FPPA等重要运动。
