Liebensteiner M C, Szubski C, Raschner C, Krismer M, Burtscher M, Platzer H P, Deibl M, Dirnberger E
Institute of Sports Science, Leopold-Franzens University of Innsbruck, Innsbruck, Austria.
Knee. 2008 Jun;15(3):180-6. doi: 10.1016/j.knee.2008.01.009. Epub 2008 Mar 4.
The role of frontal plane tibiofemoral alignment in subjects with patellofemoral pain syndrome (PFPS) is controversial and rarely discussed in the literature. As well, little research has been done on the effects of the hamstrings muscles on PFPS. The aim of the current study was to determine whether, in individuals with PFPS, frontal plane tibiofemoral alignment or muscular activity of the index knee's crossing muscles is altered during maximum eccentric leg press exercise.
This cross-sectional study involved 19 patients with PFPS and 19 control subjects who were matched according to gender, age, and physical activity. During eccentric leg press action, frontal plane tibiofemoral alignment was assessed with a motion analysis system based on skin markers. Simultaneously, surface-electromyography was used to assess the activity levels of the relevant knee crossing muscles. To assess the activity under functional conditions, a leg press with a footplate having variable stability was used for barefoot testing.
The PFPS subjects did not have significantly different frontal plane leg alignment compared to controls. On electromyography (EMG), PFPS patients had significantly lower levels of hamstring activity during eccentric leg exercise. The differences between the two groups (%; absolute differences normalized EMG) ranged from 20% (semitendinosus; stable footplate; p=0.017) to 21% (biceps femoris; unstable footplate; p=0.019) and 32% (semitendinosus; unstable footplate; p=0.002).
PFPS is not linked to altered frontal plane leg alignment during eccentric leg pressing. However, PFPS is associated with eccentric under-activation of the hamstrings, which may be a compensatory strategy that maintains patellofemoral joint pressure within bearable levels.
在髌股疼痛综合征（PFPS）患者中，额状面胫股对线的作用存在争议，且在文献中很少被讨论。同样，关于腘绳肌对PFPS的影响的研究也很少。本研究的目的是确定在进行最大离心腿举运动时，PFPS患者的额状面胫股对线或患侧膝关节交叉肌肉的肌肉活动是否发生改变。
这项横断面研究纳入了19例PFPS患者和19名对照受试者，后者根据性别、年龄和身体活动情况进行匹配。在离心腿举动作过程中，使用基于皮肤标记的运动分析系统评估额状面胫股对线。同时，使用表面肌电图评估相关膝关节交叉肌肉的活动水平。为了评估功能状态下的活动，使用带有可变稳定性踏板的腿举装置进行赤脚测试。
与对照组相比，PFPS患者的额状面腿部对线没有显著差异。在肌电图（EMG）方面，PFPS患者在离心腿部运动期间腘绳肌活动水平显著降低。两组之间的差异（%；绝对差异标准化EMG）范围为20%（半腱肌；稳定踏板；p=0.017）至21%（股二头肌；不稳定踏板；p=0.019）和32%（半腱肌；不稳定踏板；p=0.002）。
PFPS与离心腿举过程中额状面腿部对线改变无关。然而，PFPS与腘绳肌离心激活不足有关，这可能是一种将髌股关节压力维持在可承受水平的代偿策略。
