4种算法评估落地动作中ACL负荷的对比研究

Comparative Study on Four Calculation Methods of ACL Load Evaluation during Landing

目的:采用4种不同的算法模型估算落地动作过程中ACL动态载荷并进行对比分析,探讨造成差异的生物力学机制。方法:选择1名女性田径项目运动员为对象,同步采集40 cm高台垂直落地动作中的下肢运动学、动力学和表面肌电数据。4种算法模型及相应技术路线分别为:1)基于逆向动力学算法模型计算胫前剪切力(ATSF_1);2)基于Paul Devita数学模型计算胫前剪切力(ATSF_2);3)采用Open Sim CMC过程优化膝关节周围肌肉群肌力,代入Paul Devita数学模型重新计算胫前剪切力(ATSF_3);4)基于Julia Kar提供的Open Sim ACL模型计算ACL拉力(F_(ACL))。结果:Open Sim CMC结果与EMG信号在曲线形态有较高的一致性;4种计算方法下所对应的落地过程中,ATSF_1、ATSF_2、ATSF_3、F_(ACL)峰值分别为1.1BW、2.0BW、4.5BW、1.7BW;峰值时刻分别为落地周期的62%、80%、55%、36%。结论:基于传统逆向动力学算法的ATSF_1可能低估了运动过程中的ACL载荷,可量化肌群肌力的不同算法模型下ACL载荷结果的不同,主要归因于估算肌力方法的本身差异。

Objective： This study aimed to utilize four popular modelling calculation methods to estimate and compare the loadings on ACL during landing, and to investigate the biomechanical principle behind the differences. Methods： choosing a female athlete performed jumping landing from a 40 cm platform with the kinematics, kinetics, and EMG of the lower extremities recorded by the 3 D infrared motion capture system, 3 D force plate, and EMG recording system. Four calculation methods were as follows： 1） calculate the anterior tibia shear force based on inverse dynamic method（ATSF1）; 2） calculate the anterior tibia shear force based on Paul Devita＇s mathematical model（ATSF2）; 3） calculate the muscle forces around the knee joint by Open Sim CMC optimization, then introduce the muscle forces into Paul Devita＇s model to recalculate the anterior tibia shear force（ATSF3）; 4） calculate the force on ACL based on the knee model in Open Sim offered by Julia Kar（FACL）. Results： The results from the Open Sim CMC optimization corresponded very well with the curve patterns of the EMG signals. The peak values of loadings on ACL during landing were 1.1 BW（ATSF1）, 2.0 BW（ATSF2）, 4.5 BW（ATSF3）, 1.7 BW（FACL）. The times when the peaks occurred during landing were 62%（ATSF1）, 80%（ATSF2）, 55%（ATSF3）, 36%（FACL）. Conclusion： The traditional inverse dynamic method through calculating ATSF underestimated the loadings on ACL because it failed to quantify the muscle forces. Differences in ACL loading results under different algorithmic models that quantify the muscle force are mainly due to differences in methods of estimating muscle force.