Strengthening Routine to Prevent ACL Injuries

Strengthening Muscles That Support the Anterior Cruciate Ligament

Anterior cruciate ligament (ACL) injuries, including sprains or tears, are among the most common knee injuries athletes endure. While accidents are bound to happen, there are ways to help strengthen the supporting muscles of the knee and help prevent injury or unnecessary strain on the knee.

A woman doing lunges with weights
Erik Isakson / Getty Images

This strengthening program focuses on increasing strength in the leg muscles. This will lead to increased leg strength and a more stable knee joint. Remember, the technique is everything; pay close attention to your form during the performance of these exercises to avoid injury. Here are three exercises to strengthen leg muscles and prevent an ACL injury.

Quadriceps Strengthening Exercise to Prevent ACL Injury

The quadriceps muscles are four separate muscles in the front of the thigh.

Walking Lunges (3 sets x 10 reps)

  • Elapsed Time: 6.5 - 7.5 min
  • Purpose: Strengthen the thigh (quadriceps) muscle

How to:

  • 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
  • Control the motion and try to avoid your front knee from caving inward
  • If you cannot see your toes on your leading leg, you are doing the exercise incorrectly

Hamstring Exercise to Prevent ACL Injury

The hamstring muscles are five separate tendons in the back of the thigh.

Hamstring Leans (3 sets x 10 reps)

  • Elapsed Time: 7.5 - 8.5 min
  • Purpose: Strengthen hamstrings muscles

How to:

  • Kneel on the ground with hands at your sides
  • 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
  • You should feel the hamstrings in the back of your thigh working
  • Repeat the exercise for 3 sets of 10, or a total of 30 reps

Balance Exercise to Prevent ACL Injury

Studies show that lower hamstring strength vs. quadricep strength may play a part in ACL injury. Therefore, increasing balance is shown to help create an equilibrium between the strength of the quadriceps muscles vs. the hamstring muscles.

Single Toe Raises (30 reps x 2 sets)

  • Elapsed Time: 8.5 - 9.5 min
  • Purpose: The single-toe raise strengthens the calf muscle and increases balance

How to:

  • Stand up with your arms at your sides
  • Bend the left knee up and maintain your balance
  • Slowly rise up on your right toes with good balance
  • You may hold your arms out ahead of you in order to help
  • Slowly repeat 30 times and switch to the other side

As you get stronger, you may need to add additional repetitions to this exercise to continue the strengthening effect of the exercise. There are dynamic exercises that when coupled with these will also help strengthen supporting muscles and prevent ACL injury.

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Padua DA, Marshall SW. Evidence Supporting ACL-Injury-Prevention Exercise Programs: A Review of the LiteratureAthletic Therapy Today. 2006;11(2):11-23. doi:10.1123/att.11.2.11

  2. Nessler T, Denney L, Sampley J. ACL Injury Prevention: What Does Research Tell Us?Curr Rev Musculoskelet Med. 2017;10(3):281–288. doi:10.1007/s12178-017-9416-5

Additional Reading
  • PEP Program. Santa Monica Sports Medicine Research Foundation.

By Elizabeth Quinn
Elizabeth Quinn is an exercise physiologist, sports medicine writer, and fitness consultant for corporate wellness and rehabilitation clinics.