Exercises to Help Rehabilitate Your ACL Injury

The anterior cruciate ligament (ACL), is one of the key support structures of your knee. A torn ACL is a common injury among athletes or physically active people. Minimally invasive arthroscopic surgery is highly successful for the treatment of this problem. Following the surgical procedure, you will most likely be referred to physical therapy for specific rehabilitation exercises that are most appropriate for you.

Diagram of anterior cruciate ligament.

Ellen Lindner / Verywell

Goals of Rehabilitation

While you should always follow the rehabilitation program prescribed by your healthcare provider or therapist, the following general rehabilitation protocol gives you an overview of the type of exercises and the progression through therapy that you can expect following surgery for an ACL repair.

The majority of ACL surgery patients will be prescribed a specific exercise program that focuses on regaining range of motion and gradually bearing weight on the knee. The goal of the initial rehabilitation phase is to gain full flexion and extension of the knee joint and then build balance and strength.

According the Centers for Disease Control and Prevention (CDC), ACL joint injuries are commonly associated with diminished hamstring strength. Much of the rehabilitation should be focused on strengthening these stabilizing muscles.

There is a standard progression of exercises over the 12- to 14-week program. Your program may vary based on the speed of your recovery. The following is considered a general guideline.

Weeks 1 to 2

Following surgery, you should meet with your physical therapist for an initial evaluation and to learn how to perform your home exercise program. In most cases, you will be advised to focus on range-of-motion exercises and gradual weight bearing on the knee.

  • Slowly wean yourself off crutches and begin bearing weight as tolerated.
  • Build a range of motion from 0 to 75 degrees in the knee.
  • Work toward achieving full knee extension.
  • Begin passive knee extension exercises. Sit in a chair and place your heel on another chair of equal height. Relax your leg and allow your knee to straighten. Rest in this position 1 to 2 minutes several times a day to stretch out the hamstrings.
  • Begin straight leg raises to build strength.

Weeks 2 to 4

The next two weeks, you will continue to increase your range of motion, increase quadriceps strength, and perform easy balance exercises.

  • Build a range of motion from 0 to 110 degrees.
  • Start heel slides. Sit on the floor with legs outstretched. Slowly bend the knee of your injured leg while sliding your heel/foot across the floor toward you. Slide back into the starting position and repeat 10 times.
  • Start isometric contraction of the quadriceps. Sit on the floor with your injured leg straight and your other leg bent. Contract the quadriceps of the injured knee without moving the leg by pressing down against the floor. Hold for 10 seconds. Relax. Repeat 10 times.
  • Start half-squats, partial lunges, and calf raises as tolerated and as directed.
  • Half-Squat: Stand holding a sturdy table with both hands. With your feet placed shoulder’s width apart, slowly bend your knees and squat, lowering your hips into a half-squat. Hold 10 seconds and then slowly return to a standing position. Repeat 10 times.
  • Partial Lunges: Stand holding a sturdy table with both hands. With your feet placed shoulder’s width apart, take a half step forward, keeping your weight evenly distributed. Slowly bend your knees and sink down slightly. Hold 10 seconds and then slowly return to a standing position. Repeat on the other side. Do 10 times per side.
  • Heel Raises: While standing, place your hand on a counter or back of a chair for balance. Raise up onto your toes and hold for five seconds. Slowly lower your heel to the floor and repeat 10 times.
  • Begin stationary bicycling, water exercise (swimming), and upper-body strength training as directed.
  • Begin balance and proprioception exercises as directed.

Weeks 4 to 6

During the next two weeks, you will continue to build a range of motion and balance while you add some resistance to your strengthening exercises.

  • Continue building a range of motion per your therapist's directions.
  • Increase strength-building exercises with resistance (hold light hand weights or use elastic tubing or stretch cords as directed)
  • If directed, begin prone knee flexion exercises. Lie on your stomach with your legs straight. Bend your knee and bring your heel toward your buttocks. Hold for five seconds. Relax. Repeat 10 times.
  • Begin single-leg exercises, such as one-leg half squats and climbing stairs.
  • One-legged balance: As tolerated, stand unassisted on the injured leg for 10 seconds. Work up to this exercise over several weeks.
  • Begin core stabilization exercises as directed.
  • Continue balance and proprioception exercises.
  • Increase the intensity of aerobic exercise to increase heart rate.
  • Begin using endurance equipment such as the stair climber or elliptical trainer if tolerated.

Weeks 6 to 8

During these weeks, you will progress with the previous exercises. Generally, your therapist will recommend lateral (side-to-side) stepping and lateral step-ups and step-downs. Because everyone progresses at their own pace, it's important to follow your therapist's instructions regarding these exercises, your progression, and limitations.

Weeks 8 to 12

Continue building strength and range of motion in the next month.

  • Build strength during knee flexion.
  • Knee extension strengthening exercise: You may be given an elastic band for this exercise. If so, loop one end of the band around a table leg and the other around the ankle of your injured leg. While facing the table, bend your knee to 45 degrees against the resistance of the tubing, then return to the starting position.

Weeks 12 to 14

By this time, many patients are ready to begin light jogging. Agility and plyometric exercise may also be introduced.

At a follow-up visit with your surgeon or healthcare provider, functional tests will be performed to evaluate the success of the rehabilitation program. If cleared, you will be provided a specific plan on how to return safely to sports without re-injuring yourself.

According to research published in 2017 in the Orthopedic Journal of Sports Medicine, the risk of a repeat ACL injury within 24 months is six times greater than in someone who has never had an ACL tear.

​However successful your treatment and rehabilitation may have been, it is important to follow the ACL injury prevention guidelines to reduce your risk of future injury.

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  1. Myer GD, Paterno MV, Ford KR, Hewett TE. Neuromuscular training techniques to target deficits before return to sport after anterior cruciate ligament reconstruction. J Strength Cond Res. 2008;22(3):987-1014. doi:10.1519/JSC.0b013e31816a86cd