Crouzier Marion, Hug François, Sheehan Frances T, Collins Natalie J, Crossley Kay, Tucker Kylie
Laboratory "Movement, Interactions, Performance" (UR 4334), University of Nantes, Nantes, France.
Université Côte d'Azur, LAHMESS, Nice, France.
Orthop J Sports Med. 2023 Jun 7;11(6):23259671231155894. doi: 10.1177/23259671231155894. eCollection 2023 Jun.
An alteration in the force distribution among quadriceps heads is one possible underlying mechanism of patellofemoral pain. However, this hypothesis cannot be directly tested as there are currently no noninvasive experimental techniques to measure individual muscle force or torque in vivo in humans. In this study, the authors considered a combination of biomechanical and muscle activation measures, which enabled us to estimate the mechanical impact of the vastus medialis (VM) and vastus lateralis (VL) on the patella.
PURPOSE/HYPOTHESIS: The purpose of this study was to determine whether the relative index of torque distribution for the VM and VL differs between adolescents with and without patellofemoral pain. It was hypothesized that, relative to the VL, the VM would contribute less to knee extension torque in adolescents with patellofemoral pain compared with controls.
Cross-sectional study; Level of evidence, 3.
Twenty adolescents with patellofemoral pain and 20 matched control participants were included (38 female; age, 15.3 ± 1.8 years; weight, 58 ± 13 kg; height, 164 ± 8 cm). Muscle volumes and resting moment arms were quantified from magnetic resonance images, and fascicle lengths were obtained from panoramic B-mode ultrasonography. Muscle activation was estimated using surface electromyography during submaximal isometric tasks (wall-squat and seated tasks). Muscle torque was estimated as the product of muscle physiological cross-sectional area (ie, muscle volume/fascicle length), muscle activation (normalized to maximal activation), and moment arm.
Across tasks and force levels, the relative contribution of the VM to the overall medial and lateral vastii torque was 31.0% ± 8.6% for controls and 31.5 ± 7.6% for adolescents with patellofemoral pain (group effect, > .34).
For the tasks and positions investigated in this study, the authors found no evidence of lower VM torque generation (relative to the VL) in adolescents with patellofemoral pain compared with controls.
股四头肌各头之间力分布的改变是髌股疼痛的一种可能潜在机制。然而，由于目前尚无在人体体内测量个体肌肉力量或扭矩的非侵入性实验技术，这一假设无法直接得到验证。在本研究中，作者考虑了生物力学和肌肉激活测量方法的结合，这使我们能够估计股内侧肌（VM）和股外侧肌（VL）对髌骨的力学影响。
目的/假设：本研究的目的是确定有和没有髌股疼痛的青少年中，VM和VL扭矩分布的相对指数是否存在差异。研究假设是，相对于VL，与对照组相比，患有髌股疼痛的青少年中VM对膝关节伸展扭矩的贡献较小。
横断面研究；证据等级，3级。
纳入20名患有髌股疼痛的青少年和20名匹配的对照参与者（38名女性；年龄，15.3±1.8岁；体重，58±13kg；身高，164±8cm）。从磁共振图像中量化肌肉体积和静息力臂，并通过全景B型超声获得肌纤维长度。在次最大等长任务（靠墙蹲和坐姿任务）期间使用表面肌电图估计肌肉激活。肌肉扭矩估计为肌肉生理横截面积（即肌肉体积/肌纤维长度）、肌肉激活（归一化为最大激活）和力臂的乘积。
在所有任务和力水平下，VM对股内外侧肌总扭矩的相对贡献，对照组为31.0%±8.6%，患有髌股疼痛的青少年为31.5±7.6%（组间效应，P>.34）。
对于本研究中所调查的任务和姿势，作者发现没有证据表明与对照组相比，患有髌股疼痛的青少年中VM产生的扭矩较低（相对于VL）。
