What is the Role of my Anterior Cruciate Ligament (ACL)?

The human knee is one of the most complex hinge joints in the body and is responsible for absorbing shock and providing stability when in motion. Whether walking, running, or even standing, the ligaments in your knee are responsible for providing stability. Ligaments are the fibrous bands connecting bone to bone. There are 4 ligaments that connect your femur (upper leg/thigh bone) and tibia (lower leg/shin bone). One of those 4 ligaments is the Anterior Cruciate Ligament (ACL) which runs diagonally through the knee, from the lateral aspect of the femur to the medial tibia. One of the primary functions of the ACL is to prevent the tibia from translating forward on the femur.

a diagram of the anatomy of the knee and the ACL ligament

While standing can put strain on the knee, engaging in sports that require change of direction, jumping, and pivoting can put additional strain on the ligaments in your knee, specifically your ACL. When the ACL is injured or torn, the knee lacks inherent stability and may require ACL reconstruction surgery.  Each year, approximately 350,000 ACL reconstructions are performed in the United States and roughly one million worldwide¹. Taking preventative action with these 4 tips will help reduce your chances of experiencing an ACL injury:

Proper Pre-Workout Warm Up

Performing a proper warm-up regimen before exercising or participating in sporting events can reduce the chance of injury to the ACL, amongst other parts of the body. Properly warming up with dynamic movements will increase blood flow to muscles resulting in improved elasticity, which will reduce the amount of stress put on ligaments and joints throughout the body. Here are a few effective warm-up drills to try before exercising:

  • Forward Walking or Running– For 1-2 minutes, focus on lifting your knees and landing on the ball of your foot to better engage your calves, hamstrings, and glutes. Start off slow and increase your pace as you feel comfortable.

 

  • Backward Walking or Running– For 1-2 minutes, have a slight lean forward driving your legs backwards to engage the muscles in your quadriceps more. Start off slow and increase your pace as you feel comfortable.

 

  • Side Shuffle– Start in an athletic stance with a slight bend in your knees. Lead with your right foot moving to the right and the left foot pushing off and following. Always keep your weight on the balls of your feet while keeping about 12 inches between your feet. After 30-60 seconds, be sure to switch directions to engage your hips, glutes, and quadriceps equally.

Strengthening for Your Knees

While running, jumping, pivoting, and performing activities, our bodies fatigue and musculoskeletal alignment strains, putting stress on our joints. Strengthening the muscles around the hip, knee, and entire lower extremity chain can keep your hip, knee, and ankle in proper alignment, which aids in reducing stress to joints and ultimately, injuries. These exercises should be performed with minimal to no pain. If you do experience pain while performing these exercises, consult a medical professional.

  • Bridges– While lying on your back with your feet on the floor, hip-width apart, tighten your abdominals, squeeze your glutes, and lift your hips off of the floor. Be sure to avoid arching your back. Hold the bridge position for 2-3 seconds and then return to starting position. Repeat 10 times for 2-3 sets, twice a week.

 

  • Clamshells – While lying on your side with your knees bent and legs together, keep your feet together and lift your top knee until it is parallel with your hip. Be sure to avoid rotation at your hip or back. Hold your leg up for 2-3 seconds and then lower to starting position. Repeat 10 times for 2-3 sets and then switch sides.

 

  • Lunges– Standing with your feet about hip-width apart, take a large step forward with your right leg and lower your thigh until parallel with the floor. Pretend you are going to pick up two suitcases that are along your sides. Your knee should be directly above your ankle- and remember to keep your torso upright so that you do not lean forward. Press into your right heel to engage your glutes and return to standing position. Repeat 10 times each leg for 2-3 sets twice a week.

Athletic Stance

When engaging in multi-directional sports, it is always important to be in an athletic stance. This stance can vary from sport to sport, but it will allow you to quickly accelerate, decelerate, and change directions quickly without adding stress to your knees.

  • Start with your feet wider than your shoulders
  • Position knees inside of your feet with toes pointing forward
  • Your chest should be positioned over your feet with a neutral spine

Injury Prevention Screen

Excessive strain can be placed on the ACL when performing lateral movements, pivoting, or when performing activities such as running, jumping, and landing with improper mechanics. At IMPACT Physical Therapy, our physical therapists are movement specialists who can perform functional movement assessments to identify asymmetries and movement impairments that can contribute to strain/stress on the body and increase risk for injuries. During the screen, a therapist will take you through fundamental movement patterns and sport-specific activities and will assess your body’s mobility, ability to stabilize while moving, mechanics, and symmetry. Once the assessment is complete, the physical therapist will recommend exercises that will assist in improving alignment and body mechanics to improve movement patterns and function.

What to Do if You Suspect an ACL Injury

If a suspected ACL injury occurs, please consult with your physician or physical therapist for proper evaluation and treatment. Whether you decide on a non-surgical or surgical course of treatment, our clinicians at IMPACT Physical Therapy are here to guide you through your ACL rehabilitation. If you are planning your post-surgical rehabilitation, our ACL Rehab and Return to Play Program utilizes a comprehensive protocol created with your sports medicine team. The program focuses on pre- and post-surgery treatments; specifically, improving range of motion, strength, and ultimately getting you back to full function so that you can return to participation. Contact us today to talk to one of our ACL rehab specialists or to schedule a consultation!

 

References

¹. The Effectiveness of a Functional Knee Brace on Joint-Position Sense in Anterior Cruciate Ligament-Reconstructed Individuals.

Sugimoto D, LeBlanc JC, Wooley SE, Micheli LJ, Kramer DE

J Sport Rehabil. 2016 May; 25(2):190-4.