Willson John D, Sharpee Ryan, Meardon Stacey A, Kernozek Thomas W
Department of Physical Therapy, East Carolina University, Greenville, NC 28734, USA.
La Crosse Institute for Movement Science, Department of Health Professions - Physical Therapy Program, University of Wisconsin - La Crosse, La Crosse, WI 54601, USA.
Clin Biomech (Bristol). 2014 Mar;29(3):243-7. doi: 10.1016/j.clinbiomech.2013.12.016. Epub 2013 Dec 30.
Patellofemoral pain is common among runners and is frequently attributed to increased patellofemoral joint stress. The purpose of our study was to examine the effects of changing step length during running on patellofemoral joint stress per step and stress per mile in females with and without patellofemoral pain.
Ten female runners with patellofemoral pain and 13 healthy female runners performed running trials at 3.7m/s in three conditions: preferred step length, at least +10% step length, and at least -10% step length. Knee flexion angles and internal knee extension moments served as inputs for a biomechanical model to estimate patellofemoral joint stress per step. We also estimated total patellofemoral joint stress per mile based on the number of steps necessary to run a mile during each condition.
Patellofemoral joint stress per step increased 31% in the long step length condition (P<.001) and decreased 22.2% in the short step length condition (P<.001). Despite the inverse relationship between step length and number of steps required to run a mile, patellofemoral joint stress per mile increased 14% in the long step length condition (P<.001) and decreased 7.5% in the short step length condition (P<.001).
These results suggest a direct relationship between step length and patellofemoral joint loads. Total stress per mile experienced at the patellofemoral joint decreased with a short step length despite the greater number of steps necessary to cover this distance. These findings may have relevance with respect to both prevention and treatment of patellofemoral joint pain.
髌股关节疼痛在跑步者中很常见，通常归因于髌股关节压力增加。我们研究的目的是检查跑步时改变步长对有或无髌股关节疼痛的女性每步髌股关节压力以及每英里压力的影响。
10名患有髌股关节疼痛的女性跑步者和13名健康女性跑步者在三种条件下以3.7米/秒的速度进行跑步试验：偏好步长、至少增加10%步长和至少减少10%步长。膝关节屈曲角度和膝关节内伸力矩作为生物力学模型的输入，以估计每步髌股关节压力。我们还根据每种条件下跑一英里所需的步数来估计每英里髌股关节的总压力。
在长步长条件下，每步髌股关节压力增加31%（P<0.001），在短步长条件下减少22.2%（P<0.001）。尽管步长与跑一英里所需步数呈反比关系，但在长步长条件下，每英里髌股关节压力增加14%（P<0.001），在短步长条件下减少7.5%（P<0.001）。
这些结果表明步长与髌股关节负荷之间存在直接关系。尽管短步长跑相同距离所需步数更多，但髌股关节每英里承受的总压力却降低了。这些发现可能与髌股关节疼痛的预防和治疗都有关。
