How biomechanical factors and compensatory strategies influence joint contact forces?

许多研究报道，个体特征（如年龄、性别、遗传因素）和生物力学因素（如体重、机械对齐）的差异可能使关节易患退行性疾病。研究还报道，一些代偿策略（例如，增加脚趾向外角度，增加躯干倾斜）经常被个人在日常活动中（有意或无意）采用，以应对关节疾病，以尽量减少疼痛。为了量化这些策略的效率，作者通常报道了步态中下肢关节力矩的减少。然而，最近的研究质疑这些参数对最小化关节接触力的真正影响。根据我们的知识，在功能性任务（例如，楼梯上升和下降，坐姿到站立的转换）中，代偿策略的影响以及它们与生物力学因素的相互作用对关节完整性的影响知之甚少（即，关节完整性的保存可以表示为关节接触面上负载的最佳分布的结果）。

Many studies have reported that individual characteristics (e.g., age, sex, genetic factors) and differences in biomechanical factors (e.g., body weight, mechanical alignment) may predispose the joint to degenerative diseases. Studies also report that some compensatory strategies (e.g., increased toe-out angle, increase trunk lean) are often adopted by individuals during daily activities (consciously or not) to cope with joint disorders in order to minimize pain. To quantify the efficiency of these strategies, authors generally reported the reduction of lower joint moments during gait. However, recent studies have questioned the real impact of these parameters on the minimization of joint contact forces. Based on our knowledge, little is known about the influence of compensatory strategies as well as their interaction with biomechanical factors on joint integrity (i.e., the preservation of joint integrity could be represented as the result of optimal distribution of loads on joint contact surfaces) during functional tasks (e.g., stair ascent and descent, sit-to-stand transition). The long term goal of the proposed research program is to better understand both the influence of biomechanical factors and compensatory strategies on lower body joint integrity in a dynamic context of evaluation. The specific objectives will be (1) to determine the contribution of biomechanical factors on the magnitude of lower joint moments during functional tasks (i.e., level gait, sit-to-stand, stair ascent and descent); (2) to determine the contribution of compensatory strategies on the minimization of lower joint moments during functional tasks (i.e., level gait, sit-to-stand, stair ascent and descent); (3) to use a musculoskeletal model to quantify the contribution of compensatory strategies to the reduction of joint moments and minimization of joint contact forces at the lower limb and; (4) to use a complex statistical approach to better understand the interactions between biomechanical factors and compensatory strategies on the control of joint contact forces during functional tasks. This research program will contribute significantly to the understanding of biomechanical factors and compensatory strategies that have a major contribution on the reduction of joint contact forces during functional tasks. More specifically, it will contribute to increase our knowledge about the interactions between biomechanical factors, whole-body mechanisms and human intrinsic characteristics having significant impact on mechanical joint integrity and their possible future contribution to the degeneration of mechanical-biological properties associated with the various joints (e.g., knee, hip). Finally, the proposed program will add knowledge related to compensatory strategies used by individuals to reduce joint loads.