Ishida Tomoya, Samukawa Mina, Koshino Yuta, Ino Takumi, Kasahara Satoshi, Tohyama Harukazu
Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
Faculty of Health Sciences, Hokkaido University of Science, Sapporo, Japan.
Orthop J Sports Med. 2023 Jun 29;11(6):23259671231182105. doi: 10.1177/23259671231182105. eCollection 2023 Jun.
Although double-leg squatting is less dynamic and places less demand on the quadriceps compared with landing tasks, the relationship between double-leg squatting biomechanics and persistent quadriceps weakness after anterior cruciate ligament reconstruction (ACLR) is unknown.
To clarify the relationships between asymmetries in quadriceps strength and lower limb biomechanics during double-leg squatting >1 year after ACLR.
Controlled laboratory study.
A total of 26 participants (5.5 ± 3.8 years after ACLR) were enrolled. The limb symmetry index (LSI) of isokinetic quadriceps strength was used to divide participants into the high-quadriceps (HQ) group (LSI ≥90%; n = 18) and the low-quadriceps (LQ) group (LSI <90%; n = 8). The knee, hip, and ankle extension moment (relative to body weight and support moment [sum of knee, hip, and ankle moments]) and vertical ground-reaction force during double-leg squatting were analyzed using 3-dimensional motion analysis. The association of quadriceps strength and biomechanical variables was tested using 2-way analysis of variance and univariate regression analysis.
A significant group-by-limb interaction was found for the peak knee extension moment and the ratios of knee and hip extension moment to support moment ( < .001, = .015 and < .001, respectively). The LQ group showed a significantly smaller peak knee extension moment and knee to support moment ratio but a larger hip to support moment ratio in the involved limb than in the uninvolved limb (95% CIs: knee extension moment, -0.273 to -0.088 N·m/kg; knee to support moment ratio, -10.7% to -2.2%; hip to support moment ratio, 3.2% to 8.5%). No interlimb difference was found for the HQ group. The LSI of quadriceps strength was significantly associated with the LSI of peak knee extension moment ( = 0.183), knee to support moment ratio ( = 0.256), and hip to support moment ratio ( = 0.233). The mean maximum isokinetic quadriceps strength and peak knee extension moment during squatting on the involved limb of the LQ group were 2.40 ± 0.39 and 0.90 ± 0.16 N·m/kg, respectively.
Asymmetrical biomechanics during double-leg squatting was associated with persistent quadriceps weakness after ACLR. The LQ group had reduced knee extensor moment on the involved side during squatting despite loading at approximately half the maximum strength.
Quadriceps strengthening exercises, together with interventions to improve neuromuscular control, may reduce asymmetrical biomechanics during double-leg squatting.
尽管与落地任务相比，双腿深蹲的动态性较低，对股四头肌的需求也较小，但前交叉韧带重建（ACLR）后双腿深蹲生物力学与股四头肌持续无力之间的关系尚不清楚。
阐明ACLR术后1年以上双腿深蹲时股四头肌力量不对称与下肢生物力学之间的关系。
对照实验室研究。
共纳入26名参与者（ACLR术后5.5±3.8年）。使用等速股四头肌力量的肢体对称指数（LSI）将参与者分为高股四头肌（HQ）组（LSI≥90%；n = 18）和低股四头肌（LQ）组（LSI<90%；n = 8）。使用三维运动分析来分析双腿深蹲时的膝关节、髋关节和踝关节伸展力矩（相对于体重和支撑力矩[膝关节、髋关节和踝关节力矩之和]）以及垂直地面反作用力。使用双向方差分析和单变量回归分析来测试股四头肌力量与生物力学变量之间的关联。
在峰值膝关节伸展力矩以及膝关节和髋关节伸展力矩与支撑力矩的比值方面发现了显著的组×肢体交互作用（分别为P<0.001，P = 0.015和P<0.001）。LQ组患侧在深蹲时的峰值膝关节伸展力矩和膝关节与支撑力矩的比值明显较小，但髋关节与支撑力矩的比值比未患侧大（95%可信区间：膝关节伸展力矩，-0.273至-0.088N·m/kg；膝关节与支撑力矩的比值，-10.7%至-2.2%；髋关节与支撑力矩的比值，3.2%至8.5%）。HQ组未发现肢体间差异。股四头肌力量的LSI与峰值膝关节伸展力矩的LSI（r = 0.183）、膝关节与支撑力矩的比值（r = 0.256）以及髋关节与支撑力矩的比值（r = 0.233）显著相关。LQ组患侧在深蹲时的平均最大等速股四头肌力量和峰值膝关节伸展力矩分别为2.40±0.39和0.90±0.16N·m/kg。
双腿深蹲时的不对称生物力学与ACLR后股四头肌持续无力有关。尽管负荷约为最大力量的一半，但LQ组在深蹲时患侧的膝关节伸肌力矩仍降低。
股四头肌强化训练以及改善神经肌肉控制的干预措施可能会减少双腿深蹲时的不对称生物力学。
