ACL injury mechanisms & offaxis neuromuscular diagnosis & training

描述(申请人提供)：前交叉韧带是运动相关活动，特别是旋转运动中最常见的膝关节韧带损伤。前交叉韧带损伤的机制，包括导致女性运动员的发病率是男性运动员的2-9倍的因素，仍然不是很清楚。考虑到膝关节的离轴运动(胫骨旋转和外翻/内翻)相当有限，而且在离轴属性上可能存在性别差异，前交叉韧带损伤往往与过多的离轴负荷有关。目的：研究男性和女性非接触性前交叉韧带损伤的离轴神经力学和解剖学特征，并根据诊断结果进行干预训练，以提高对高风险、潜在损伤的离轴运动的神经肌肉控制。假设1：女性在胫骨内外旋转、外翻和内翻时稳定性、僵硬和强度较低，关节松弛较大，本体感觉较不敏感。具体目标1：使用用于离轴评估的定制膝关节装置和一种新型的旋转-滑动椭圆机，在训练前对女性和男性的膝关节离轴神经力学特性进行诊断。还将进行临床/功能措施。假设2：在胫骨外旋转和外翻负荷下，女性比男性更有可能发生前交叉韧带撞击，其特征是特定于受试者的FE撞击模型。具体目标2：使用三维有限元前交叉韧带撞击模型，确定在胫骨外旋转和外翻过程中，前交叉韧带撞击外侧切迹壁的易感性。假设3：基于诊断的旋转-滑动椭圆训练机上的特定受试者训练改善了离轴神经肌肉控制。具体目标3：在训练前诊断的基础上，进行受试者特定的旋转-滑动椭圆训练，改善离轴神经肌肉控制。具体目标4：确定训练引起的神经机械和功能变化。研究设计地点：将确定个别受试者的离轴神经力学特性。将相应地实施干预计划。单位：一个神经机械评估研究实验室，以及一个用于培训/评估的学校健身房。对象：来自当地高中和青少年运动队的女运动员和男运动员各60名。干预：使用新型旋转滑动椭圆机训练离轴神经肌肉控制。培训将在每周三个40分钟的培训课程中进行，为期6周。观察指标：稳定性、肌力、僵硬、松弛、本体感觉、胫骨旋转(旋转)和外翻/内翻的反应时间、功能活动和前交叉韧带损伤的发生率。公共卫生相关性：拟议的研究将对男女受试者在内旋和外旋以及外翻/内翻中的离轴神经力学特性进行特定受试者的诊断，并根据诊断结果使用新型旋转-滑动椭圆机进行离轴神经肌肉控制的特定受试者干预训练。

DESCRIPTION (provided by applicant): ACL is the most commonly injured knee ligament in sports-related activities, especially in pivoting sports. ACL injury mechanisms, including factors contributing to the 2-9 times higher incident rate in female athletes than their male counterparts, are still not very clear. Considering off-axis knee motions (tibial rotation and valgus/varus) are rather limited and there may be gender differences in off-axis properties, ACL injuries are often associated with excessive off-axis loadings. Objectives: To investigate off-axis neuromechanical and anatomical properties of noncontact ACL injuries in men and women, and to conduct intervention training based on the diagnosis to improve neuromuscular control of risky, potentially injurious off-axis movements. Hypothesis 1: Females have lower stability, stiffness and strength, greater joint laxity, and less sensitive proprioception in external and internal tibial rotations and in valgus and varus than males. Specific Aim 1: To perform a pre-training diagnosis of knee off-axis neuromechanical properties in females and males using custom knee devices for off-axis evaluations and a novel pivoting-sliding elliptical machine. Clinical/functional measures will also be conducted. Hypothesis 2: Females are more likely to have ACL impingement than males under external tibial rotation and valgus loading, characterized by a subject-specific FE impingement modeling. Specific Aim 2: To determine the susceptibility of ACL impingement against the lateral notch wall during external tibial rotation and valgus in individuals using a 3-D FE ACL-impingement model. Hypothesis 3: Subject-specific training on a pivoting-sliding elliptical exercise machine based on the diagnosis improves off-axis neuromuscular control. Specific Aim 3: To conduct subject-specific pivoting-sliding elliptical training and improve off-axis neuromuscular control, based on the pre-training diagnosis. Specific Aim 4: To determine training-induced neuromechanical and functional changes. Study Design Setting: Off-axis neuromechanical properties will be determined for individual subjects. An intervention program will be conducted accordingly. Setting: A research lab for neuromechanical evaluations, and school gym for training/evaluation. Participants: 60 female and 60 male athletes from local high school and youth sports teams. Interventions: Training off-axis neuromuscular control using a novel pivoting-sliding elliptical machine. Training will be done in three 40-minute training session per week for 6 weeks. Outcome Measures: Stability, muscle strength, stiffness, laxity, proprioception, and reaction time in tibial rotation (pivoting) and in valgus/varus, functional activities, and incidence of ACL injuries. PUBLIC HEALTH RELEVANCE: The proposed studies will conduct subject-specific diagnosis on off-axis neuromechanical properties in internal and external rotations and in valgus/varus in individual female and male subjects, and perform subject-specific intervention training of off-axis neuromuscular control based on the diagnosis, using a novel pivoting-sliding elliptical machine.