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How to prevent an ACL injury

Posted on Jun. 30, 2017 ( comments)
Girls playing volleyball

An ACL rupture is certainly one of the most serious knee injuries in sport. The anterior cruciate ligament (ACL) helps stabilize your knee joint and can become torn during sports that involve sudden stops and changes in direction.

Many prevention programs have been developed in an attempt to address potential deficits in strength and coordination of the stabilizing muscles around the knee joint. One popular program is the Prevent Injury, Enhance Performance (PEP) program developed by a team of physicians, therapists and athletic trainers.

The PEP program can be done on a field. It requires no special equipment, takes approximately 15 to 20 minutes and should replace your standard warm-up routine. The exercises should be completed in the order listed below two or three times each week.

*The PEP exercises described here are for athletes who are at least 12 years old.


Avoidance, the first step of the program, stresses avoiding injury by teaching good running technique. Concentrate on keeping the knees flexed and the hips and knees over the ankles. The three avoidance exercises should be done with little or no rest between each one. They also serve as a warm-up for the flexibility exercises that follow.

1. Jogging

2. Shuttle Run with Sidestepping

3. Backward Run

Do each of these exercises by running 40 to 50 yards, two times.


Flexibility, or stretching, follows the avoidance exercises. Never stretch a cold muscle. By performing these stretches, you can improve your range of motion, reduce joint stiffness and reduce post-exercise soreness, reduce the risk of injury and improve your overall performance.

General guidelines for stretching

  • Do a large muscle warm-up such as light running/jogging for five to 10 minutes before stretching.
  • Don’t bounce or jerk when you stretch.
  • Gently stretch to a point of tension and hold.
  • Hold the stretch for 30 seconds. Concentrate on lengthening the muscles when you’re stretching. Repeat two times on each side.
  • Breathe normally. Don’t hold your breath.

1. Calf Stretch

Stand leading with your right leg. Bend forward at the waist and place your hands on the ground (V formation). Keep your right knee slightly bent and your left leg straight. Make sure your left foot is flat on the ground. Hold for 30 seconds. Switch sides and repeat.

2. Quadricep Stretch

Place your left hand on your partner’s left shoulder. Reach back with your right hand and grab the front of your right ankle. Bring your heel to buttock. Make sure you are standing up straight and your knee is pointed down toward the ground. Hold for 30 seconds and switch sides.

3. Figure-Four Hamstring

Sit on the ground with your right leg extended out in front of you. Bend your left knee and rest the bottom of your foot on your right inner thigh. With a straight back, try to bring your chest toward your knee. Try not to round your back over. If you can, reach down toward your toes and pull them up toward your head. Hold for 30 seconds and repeat with the other leg.

4. Inner Thigh Stretch

Remain seated on the ground. This time, spread your legs evenly apart. Slowly lower yourself to the center with a straight back. You want to feel a stretch in the inner thigh. Now reach toward the right with the right arm. Bring your left arm overhead the stretch over to the right. You should feel a good stretch along the left side of your waist. Hold the stretch for 30 seconds and repeat on the opposite side.

5. Hip Flexor Stretch

Lunge forward leading with your right leg. Drop your left knee down to the ground. Placing your hands on top of your right thigh, lean forward with your hips. The hips should be square with your shoulders. If possible, maintain your balance and lift back for the left ankle and pull your heel to your buttocks. You should feel this stretch all along the left thigh. Hold for 30 seconds and repeat on the other side.


The third part of the program is strengthening, a crucial component of PEP. By increasing the strength of the muscles of the leg, you can increase the stability of the hip, knee and ankle, thereby reducing the chance of injury.

1. Walking Lunges

Lunge forward leading with your right leg. Push off with your right leg and lunge forward with your left leg. Drop the back knee straight down. Make sure that you keep your front knee over your ankle. Keep the hip/knee/ankle in alignment and the shoulders over the hips. Control the motion and try to avoid you front knee from caving inward. If you can’t see your toes on your leading leg, you are doing the exercise incorrectly. Do 30 repetitions.

2. Russian Hamstring

Kneel on the ground with hands at your side. Have a partner hold firmly at your ankles. With a straight back, lean forward leading with your hips. Your knee, hip and shoulder should be in a straight line as you lean toward the ground. Do not bend at the waist. If you feel a cramp, stop the exercise, stretch, and then resume. Repeat the exercise for three sets of 10, or a total of 30 repetitions.

3. Single Toe Raises

Stand up with your arms at your side. Bend the left knee up and maintain your balance. Slowly rise up on your right toes with good balance. Slowly repeat 30 times and switch to the other side.


Next come plyometrics. These exercises are explosive and help to build power, strength and speed. The most important element of these exercises is the landing. It must be soft! When you land from a jump, you want to softly accept your weight on the balls of your feet, slowly rolling back to the heel with a bent knee and a straight hip. By landing in this manner, you actively contract your hamstring muscles, which reinforces the ACL ligament. Be sure to take the time to perform these exercises correctly.

1. Side-to-Side Hops Over Cone

Stand with a 6-inch cone or ball to your left. Hop to the left over the cone softly landing on the balls of your feet and bending at the knee. Repeat this exercise, hopping to the right. Do 20 repetitions. To complete one rep you must jump to one side of the cone and then back to the original side.

2. Frontward/Backward Hops Over Cone

Stand facing a 6-inch cone or ball. Hop over the cone/ball softly landing on the balls of your feet and bending at the knee. Now, hop backward over the ball using the same landing technique. Be careful not to snap your knee back to straighten it. You want to maintain a slight bend to the knee. Perform 20 repetitions. To complete one repetition you must hop forward and then backward to your original spot.

3. Single Leg Hops Over Cone or Ball

Follow the previous instructions, but while standing on one foot. Alternate sides after 20 reps.

4. Vertical Jumps with Headers

Take one step forward with your right leg. Slightly bend the left leg and push off the left foot to jump straight up. Remember the proper landing technique; accept the weight on the ball of your foot with a slight bend to the knee. Do 20 repetitions and switch sides.

5. Scissors Jump

Stand forward with hands at your side. Jump forward with your right leg. Keep your right knee over your ankle. Now, push off with your right foot and propel your left leg forward into a lunge position. Look at your positioning and make sure it is correct. Be sure your knee does not cave in or out. They should be stable and directly over the ankle. Remember the proper landing technique. Do 20 times.


Agilities are the last portion of the program and involve proprioceptive training; that is, developing your sense of joint position. This allows you to train the knee joint to deal with situations encountered in a game. They are sport specific.

1. Shuttle Run with Forward/Backward Running

Set up two lines of cones using eight to 10 cones total. The lines should be about 10 yards apart. Space them so that you will make a diagonal pattern as you run from one line to the other. Starting at the first cone, sprint forward to the second cone. Run backward to the third cone. Sprint forward to the fourth cone, and so on. It should take 30 to 60 seconds to run through the course. Perform three times.

2. Diagonal Run

Set up cones as described above. Face forward and run to the first cone on the left. Pivot off the right leg (outside foot) and run to the second cone. Now pivot off the left leg and continue onto the third cone. Make sure that the inside leg or the pivot leg does not cave in. Keep a slight bend to the knee and make sure the knee stays over the ankle joint. Perform three times.

3. Bounding Run

Starting on the near sideline, run to the far side with knees up toward chest. Bring your knees up high. Land on the ball of your foot. Keep a slight bend at the knee. Your hip should be level, rather than dipping to one side or the other. Increase the distance of the run as this exercise gets easier. Perform 30 to 60 seconds.

About The Author

Dr. Mason Platt
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