Single-Leg Vertical Jump Change After Anterior Cruciate Ligament Reconstruction

Abstract

Abstract Background After anterior cruciate ligament reconstruction, patients still experience residual weakness, thus necessitating a comprehensive training program and assessment before returning to sports. The purpose was investigating the effect of a progressive resistance training program on the recovery of patients. Methods We prospectively enrolled 67 patients who underwent anterior cruciate ligament reconstruction. Four weeks after the reconstruction, 24 weeks of progressive resistance training was initiated. Demographic, questionnaire, single-leg vertical jump, and muscle strength were collected preoperatively and at 16, 28 weeks, and 1 year postoperatively. Results Of the 42 patients were finally included: 22 patients in the progressive resistance training group and 20 in the control group. At 28 weeks, the height of the single-leg vertical jump for the injured knee was 20.3 ± 1.7 and 15.7 ± 1.7 cm and the peak knee flexion angle for the injured knee was 31° ± 3° and 23° ± 2° in the progressive resistance training and control groups, respectively. The progressive resistance training group showed a significant increase in the knee extensor symmetry index after completing 24 weeks of the training program, which lasted up to 1 year postoperatively, and a decrease in the hamstrings/quadriceps ratio for the injured knee. Conclusion The progressive resistance training increases the single-leg vertical jump height and peak knee flexion angle after landing, which can, at least in part, be attributed to the increased muscle strength in patients with anterior cruciate ligament reconstruction. Improvement in lower-limb muscle strength can also improve biomechanical asymmetry during the single-leg vertical jump.