School of Health and Human Performance, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
Med Sci Sports Exerc. 2010 Apr;42(4):771-80. doi: 10.1249/MSS.0b013e3181bbeaa6.
To examine the relationships between anterior knee laxity (AKL), genu recurvatum (GR), and general joint laxity (GJL) with sagittal plane energetics in males and females during a drop jump task.
A total of 68 females and 50 males were measured for AKL, GR, and GJL and were instrumented to obtain neuromuscular and biomechanical data on their dominant limb during the initial landing phase of a 45-cm drop jump. Multiple linear regressions determined the extent to which the three joint laxity variables combined to predict hip, knee, and ankle work absorption and stiffness. Associations between joint laxity and joint kinematics, joint kinetics, and muscle activation amplitudes were also investigated to further interpret significant relationships.
Higher AKL and GJL and lower GR combined to predict greater knee work absorption (R2 = 0.210, P = 0.002) and stiffness (R2 = 0.127, P = 0.033) and lower ankle stiffness (R2 = 0.115, P = 0.048) in females. These associations were modulated through greater peak knee extensor moments and flexion angles, lower hamstring activation, and lower ankle extensor moments. In males, joint laxity had little impact on knee energetics, but a significant association was observed between greater GJL and decreased ankle stiffness (R2 = 0.209, P = 0.012), a product of both greater peak ankle flexion and decreased ankle extensor moment.
Females with greater AKL and GJL and lower GR demonstrated a landing strategy that increased work absorption and stiffness about the knee, whereas females with greater GR demonstrated a landing style that reduced knee work absorption and stiffness. The findings suggest that AKL, GR, and GJL may represent distinct risk factors and support the need to consider more comprehensive laxity profiles as they relate to knee joint function and anterior cruciate ligament injury risk.
研究男性和女性在进行 45 厘米落差跳落地初始阶段时，前膝松弛度（AKL）、膝反屈（GR）和整体关节松弛度（GJL）与矢状面能量之间的关系。
共有 68 名女性和 50 名男性接受 AKL、GR 和 GJL 的测量，并在其优势肢上进行仪器测量，以获取神经肌肉和生物力学数据，用于研究在 45 厘米落差跳的初始着陆阶段。多元线性回归确定了三个关节松弛变量组合预测髋、膝和踝关节吸收和刚度的程度。还研究了关节松弛与关节运动学、关节动力学和肌肉激活幅度之间的关系，以进一步解释显著的关系。
AKL 和 GJL 较高，GR 较低，共同预测女性的膝关节吸收（R2=0.210，P=0.002）和刚度（R2=0.127，P=0.033）增加，踝关节刚度（R2=0.115，P=0.048）降低。这些关联通过更大的峰值膝关节伸肌力矩和弯曲角度、较低的腘绳肌激活和较低的踝关节伸肌力矩来调节。在男性中，关节松弛对膝关节能量影响不大，但 GJL 较大与踝关节刚度降低（R2=0.209，P=0.012）之间存在显著关联，这是踝关节弯曲角度增加和踝关节伸肌力矩降低的结果。
AKL、GJL 较大和 GR 较低的女性表现出一种增加膝关节吸收和刚度的着陆策略，而 GR 较大的女性则表现出一种降低膝关节吸收和刚度的着陆风格。研究结果表明，AKL、GR 和 GJL 可能代表不同的风险因素，并支持需要考虑更全面的松弛度谱，因为它们与膝关节功能和前交叉韧带损伤风险有关。
