Abstract：
Landing from heights is a common movement for active-duty military personnel during training. And the additional load they carry while performing these tasks can affect the kinetics and ankle kinematic of the landing. Traditional motion capture techniques are limited in accurately capturing the in vivo kinematics of the talus. This study aims to investigate the effect of additional trunk load on the kinematics of the talocrural and subtalar joints during landing, using a dual fluoroscopic imaging system (DFIS).
Fourteen healthy male participants were recruited. Magnetic resonance imaging was performed on the right ankle of each participant to create three-dimensional (3D) models of the talus, tibia, and calcaneus. High-speed DFIS was used to capture the images of participants performing single-leg landing jumps from a height of 40 cm. A weighted vest was used to apply additional load, with a weight of 16 kg. Fluoroscopic images were acquired with or without additional loading condition. Kinematic data were obtained by importing the DFIS data and the 3D models in virtual environment software for 2D-3D registration. The kinematics and kinetics were compared between with or without additional loading conditions.
During added trunk loading condition, the medial-lateral translation range of motion (ROM) at the talocrural joint significantly increased (p < 0.05). The subtalar joint showed more extension at 44-56 ms (p < 0.05) after contact. The subtalar joint was more eversion at 40-48 ms (p < 0.05) after contact under the added trunk load condition. The peak vertical ground reaction force (vGRF) significantly increased (p < 0.05).
With the added trunk load, there is a significant increase in peak vGRF during landing. The medial-lateral translation ROM of the talocrural joint increases. And the kinematics of the subtalar joint are affected. The observed biomechanical changes may be associated with the high incidence of stress fractures in training with added load.
Fourteen healthy male participants were recruited. Magnetic resonance imaging was performed on the right ankle of each participant to create three-dimensional (3D) models of the talus, tibia, and calcaneus. High-speed DFIS was used to capture the images of participants performing single-leg landing jumps from a height of 40 cm. A weighted vest was used to apply additional load, with a weight of 16 kg. Fluoroscopic images were acquired with or without additional loading condition. Kinematic data were obtained by importing the DFIS data and the 3D models in virtual environment software for 2D-3D registration. The kinematics and kinetics were compared between with or without additional loading conditions.
During added trunk loading condition, the medial-lateral translation range of motion (ROM) at the talocrural joint significantly increased (p < 0.05). The subtalar joint showed more extension at 44-56 ms (p < 0.05) after contact. The subtalar joint was more eversion at 40-48 ms (p < 0.05) after contact under the added trunk load condition. The peak vertical ground reaction force (vGRF) significantly increased (p < 0.05).
With the added trunk load, there is a significant increase in peak vGRF during landing. The medial-lateral translation ROM of the talocrural joint increases. And the kinematics of the subtalar joint are affected. The observed biomechanical changes may be associated with the high incidence of stress fractures in training with added load.
摘要：
背景：从高处着陆是现役军人在训练期间的常见动作。他们在执行这些任务时承担的额外负载会影响着陆的动力学和脚踝运动学。传统的运动捕获技术在准确捕获距骨的体内运动学方面受到限制。这项研究旨在研究在着陆过程中附加躯干载荷对距骨和距骨下关节运动学的影响，使用双荧光成像系统（DFIS）。
方法：招募了14名健康男性参与者。对每个参与者的右脚踝进行磁共振成像，以创建距骨的三维（3D）模型，胫骨,和跟骨.使用高速DFIS捕获参与者从40厘米的高度进行单腿着陆跳跃的图像。一个加权背心被用来施加额外的负载，体重16公斤。在有或没有额外负载条件的情况下获取荧光图像。通过在虚拟环境软件中导入DFIS数据和3D模型来获得运动学数据，以进行2D-3D配准。在有或没有附加负载条件的情况下比较了运动学和动力学。
结果：在添加的中继加载条件下，滑膜关节的内外侧平移运动范围（ROM）显着增加（p<0.05）。距下关节在接触后44-56ms（p<0.05）显示出更多的伸展。在附加躯干载荷条件下接触后，距下关节在40-48ms（p<0.05）时外翻更多。峰值垂直地面反作用力（vGRF）显着增加（p<0.05）。
结论：随着后备箱负载的增加，着陆期间vGRF峰值显着增加。颅骨关节的内侧-外侧平移ROM增加。距下关节的运动学受到影响。观察到的生物力学变化可能与增加负荷的训练中应力性骨折的高发生率有关。
方法：招募了14名健康男性参与者。对每个参与者的右脚踝进行磁共振成像，以创建距骨的三维（3D）模型，胫骨,和跟骨.使用高速DFIS捕获参与者从40厘米的高度进行单腿着陆跳跃的图像。一个加权背心被用来施加额外的负载，体重16公斤。在有或没有额外负载条件的情况下获取荧光图像。通过在虚拟环境软件中导入DFIS数据和3D模型来获得运动学数据，以进行2D-3D配准。在有或没有附加负载条件的情况下比较了运动学和动力学。
结果：在添加的中继加载条件下，滑膜关节的内外侧平移运动范围（ROM）显着增加（p<0.05）。距下关节在接触后44-56ms（p<0.05）显示出更多的伸展。在附加躯干载荷条件下接触后，距下关节在40-48ms（p<0.05）时外翻更多。峰值垂直地面反作用力（vGRF）显着增加（p<0.05）。
结论：随着后备箱负载的增加，着陆期间vGRF峰值显着增加。颅骨关节的内侧-外侧平移ROM增加。距下关节的运动学受到影响。观察到的生物力学变化可能与增加负荷的训练中应力性骨折的高发生率有关。
