将非接触性前交叉韧带损伤（ACLD）患者急性期健侧下肢的等速肌力指标和表面肌电（sEMG）信号与健康人群进行对比，为ACLD患者健侧下肢继发性ACL断裂的预防提供理论依据。方法为21名前交叉韧带损伤急性期的患者为ACLD组和21名健康人为对照组，对两组实验对象进行髋屈、伸、内收、外展和膝屈、伸等速肌力测试，单腿跳跃动作时股内侧肌、股外侧肌、半腱肌、股二头肌、臀大肌的sEMG信号采集，通过独立样本t检验分析两组之间相对峰力矩、拮抗肌比率、均方根振幅、共收缩指数等指标之间的差异。结果显示ACLD患者的健侧下肢的伸膝（P=0.040）和伸髋肌力（P=0.041）降低；在单腿跳跃落地动作中，在预激活阶段表现出较低的股内侧肌激活（P=0.014）,在反应阶段表现出较低的股内侧肌（P=0.030）和臀大肌(P=0.022)激活，此外，股二头肌-半腱肌（BF-ST）的共激活水平也降低(P=0.020)。ACLD患者健侧下肢功能在损伤早期就出现了变化，这可能提示了ACLD患者面临较大对侧下肢损伤风险的原因。

Compare the isokinetic muscle strength indicators and surface electromyography (sEMG) signals of the healthy side lower limb of non-contact anterior cruciate ligament injury (ACLD) patients in the acute phase with those of healthy individuals to provide theoretical basis for the prevention of secondary ACL rupture in the healthy side lower limb of ACLD patients. The method was to divide the 21 patients with ACLD in the acute phase into the ACLD group and divide the 21 healthy individuals into the control group. Both groups of experimental subjects were subjected to isokinetic muscle strength tests for hip flexion, extension, adduction, abduction, and knee flexion, and electromyography signals of the vastus medialis, vastus lateralis, semitendinosus, biceps femoris, and gluteus maximus were collected during the single-leg jumping action. The differences between the two groups in relative peak torque, antagonist muscle ratio, root mean square amplitude, and co-contraction index were analyzed by independent sample t-test. The results showed that the extension of the knee (P=0.040) and hip flexion strength (P=0.041) were lower in the healthy side lower limb of ACLD patients; in the single-leg landing action, there was lower activation of the vastus medialis muscle in the pre-activation phase (P=0.014), lower activation of the vastus medialis (P=0.010) and gluteus maximus (P=0.002) in the reaction phase, and also lower co-activation level of the biceps femoris-semitendinosus (BF-ST) (P=0.020). The function of the healthy side lower limb of ACLD patients showed changes in the early stage of injury, which may suggest the reason why ACLD patients face a greater risk of contralateral lower limb injury.