A rehabilitation program should be started immediately after ACL reconstruction. The physician must be careful to protect the ACL reconstruction and take into account the physiological changes in the ACL during postoperative rehabilitation. It has been reported that the graft is strongest at the time of reconstruction and then undergoes necrosis, revascularization, and plastic reconstruction. The strength of the reconstruction decreases during the necrotic phase and gradually increases during the revascularization and plastic reconstruction phases. In general, mechanical stop reconstruction takes approximately 3 to 6 weeks. Patients will gradually regain function, and rehabilitation will be completed 4-6 months after surgery. An important preoperative component is health education. A preoperative rehabilitation program prepares the patient or athlete mentally for postoperative exercises. Education and the resulting independence in postoperative rehabilitation exercises can accelerate the rehabilitation process and reduce complications. Specific preoperative rehabilitation programs: 1. Heel pad towel roll passive hyperextension (Figure 1). 2.Quadriceps contraction exercises (Figure 2). 3.Straight leg raising exercises (Figure 3). 4, Active flexion exercises or active knee extension exercises with the contralateral healthy limb to help the affected limb (Figure 4). 5, Ice packs at the end of the training (Figure 5). Figure 1: Passive knee extension with a towel roll at the heel to promote early full knee extension. Figure 2: Quadriceps contraction exercises with towel rolls to synergize contraction and increase comfort. Figure 3: Postoperative brace fixed at 0° for straight leg raising exercises. Figure 4: Active flexion/active knee extension with the help of the contralateral limb (ROM of 90°-0°). The patient supports the affected limb with the healthy limb, slowly flexes the knee under gravity, and when there is a pulling sensation, the affected knee is fully straightened with the active help of the healthy limb. Figure 5: Ice application.