Department of Exercise Sciences, Brigham Young University.
J Sports Sci Med. 2010 Dec 1;9(4):572-9. eCollection 2010.
The causes of able-bodied gait asymmetries are unclear. Mild (< 3 cm) leg-length inequality (LLI) may be one cause of these asymmetries; however, this idea has not been thoroughly investigated. The purpose of this study was to investigate the nature of the relationship between LLI and able-bodied gait asymmetries. We hypothesized that subjects (n = 26) with relatively large LLI, quantified radiographically, would display less symmetrical gait than subjects with relatively small LLI. Gait asymmetries for joint kinematics and joint kinetics were determined using standard gait analysis procedures. Symmetry coefficients were used to quantify bilateral gait symmetry for sagittal-plane hip, knee, and ankle joint angles, moments, and powers. A Pearson product-moment correlation coefficient (r) was used to evaluate the relationship between LLI and the aforementioned symmetry coefficients. Also, these symmetry coefficients were compared between subjects with relatively small LLI (LLI < 1 cm; n = 19) and relatively large LLI (LLI ≥ 1 cm; n = 7). Statistically significant relationships were observed between LLI and the symmetry coefficient for knee joint moment (r = -0.48) and power (r = -0.51), and ankle joint moment (r = -0.41) and power (r = -0.42). Similarly, subjects with relatively large LLI exhibited significantly lower symmetry coefficients for knee joint moment (p = 0.40) and power (p = 0.35), and ankle joint moment (p = 0.40) and power (p = 0.22) than subjects with relatively small LLI. Degree of bilateral symmetry for knee and ankle joint kinetics appears to be related to LLI in able- bodied gait. This finding supports the idea that LLI is one cause of able-bodied gait asymmetries. Other factors, however, are also likely to contribute to these gait asymmetries; these may include other morphological asymmetries as well as asymmetrical neuromuscular input to the lower limb muscles. Key pointsModerate negative relationships were observed between mild limb-length inequality and gait symmetry for knee and ankle moment and power.Subjects with relatively large mild limb-length inequality (between 1.0 and 2.3 cm) exhibited significantly less symmetrical gait for knee and ankle joint moment and power than subjects with relatively small mild limb-length inequality (< 1 cm).These results indicate that the degree of symmetry for knee and ankle joint kinetics appears to be related to mild limb-length inequality in able-bodied gait.These results further our understanding of normal human walking and provide important background information for future studies on gait pathology associated with mild limb-length inequality.
肢体健全步态不对称的原因尚不清楚。轻度（<3cm）肢体长度不等（LLI）可能是这些不对称的原因之一；然而，这一观点尚未得到彻底研究。本研究的目的是探讨 LLI 与肢体健全步态不对称之间的关系。我们假设，通过影像学定量测量的 LLI 较大的受试者，其步态不对称性将低于 LLI 较小的受试者。通过标准步态分析程序确定关节运动学和关节动力学的步态不对称性。使用对称系数来量化矢状面髋关节、膝关节和踝关节角度、力矩和功率的双侧步态对称性。皮尔逊积矩相关系数（r）用于评估 LLI 与上述对称系数之间的关系。此外，还比较了 LLI 较小（LLI<1cm；n=19）和 LLI 较大（LLI≥1cm；n=7）受试者之间的这些对称系数。LLI 与膝关节力矩（r=-0.48）和功率（r=-0.51）以及踝关节力矩（r=-0.41）和功率（r=-0.42）的对称系数之间存在显著的关系。同样，与 LLI 较小的受试者相比，LLI 较大的受试者的膝关节力矩（p=0.40）和功率（p=0.35）以及踝关节力矩（p=0.40）和功率（p=0.22）的对称系数显著降低。膝关节和踝关节动力学的双侧对称性似乎与肢体健全步态中的 LLI 有关。这一发现支持 LLI 是肢体健全步态不对称的一个原因的观点。然而，其他因素也可能导致这些步态不对称；这些因素可能包括其他形态不对称以及下肢肌肉的不对称神经肌肉输入。关键点在轻度肢体长度不等与膝关节和踝关节力矩和功率的步态对称性之间观察到中度负相关。与 LLI 较小（<1cm）的受试者相比，LLI 较大（1.0-2.3cm）的受试者的膝关节和踝关节力矩和功率的步态对称性显著降低。这些结果表明，膝关节和踝关节动力学的对称性程度似乎与肢体健全步态中的轻度肢体长度不等有关。这些结果进一步加深了我们对正常人类行走的理解，并为与轻度肢体长度不等相关的步态病理的未来研究提供了重要的背景信息。
