What is the ACL?
The anterior cruciate ligament (ACL) is a ligament which provides stability to the knee joint. Injuries most often happen from a non-contact injury, usually from a movement such as a quick change of direction, twist, or landing from a jump.
Why are ACL tears more common in women?
ACL tears happen more commonly in women than men, with estimates ranging from 2 to 8 times more likely in women.
There are many theories as to why ACL tears are more common in women. The possible contributing factors are:
Structure: Women have wider hips than men, which makes women’s knees naturally in more of a valgus position (knees caving in). This may increase strain on the ACL and make it more prone to injury. Women also tend to have less muscle mass in general than men. Less muscle mass in the muscles surrounding the knee may also contribute to instability and therefore injury risk.
Hormones: During the menstrual cycle, the increase in release of the hormone estrogen may increase laxity in joints and ligaments.
Training: Due to gender disparities in funding for sport, strength and conditioning programs for female athletes are often not seen at the same frequency and quality levels as male athletes. This means a female athlete is more likely to have a lack of strength or stability which increases the likelihood of injury.
At the moment, more research needs to be done before we can conclusively say how much each of these factors are contributing to the disparity.
What can you do to prevent it?
Performing a variety of exercises to build strength and stability specific to the demands of your sport will help to reduce your risk of injury. The three main areas to focus on are strength, balance, and plyometrics.
Strength
Strength training increases muscle and tendon strength and flexibility. Increasing the strength and mass of muscle and tendon surrounding a joint helps to provide stability and decreases the risk of injury.
The main muscles that cross the knee joint are the quadriceps and hamstrings. It has been suggested that a lack of hamstring strength in women in particular may be a contributing factor to ACL injuries.
Balance & Proprioception
Improving balance helps to increase coordination, stability, and joint alignment which decreases risk of injury. Proprioception is an awareness of where a joint or body part is in space and is an essential part of balance.
As mentioned earlier, knee valgus (or knee caving in) is a major risk factor in ACL injuries. Improving your proprioception increases your ability to avoid excessive valgus or twisting on the knee joint.
Plyometrics & Neuromuscular Control
Plyometrics are quick, explosive movements such as a jump, hop, or quick change of direction. These movements are obviously an essential part of sport, and are also the movements that are the highest risk for injuring the ACL.
By performing these movements consciously and in a controlled environment (such as home or a gym), you can train your body to move with proper form. The more often that you perform a movement with proper form, the more likely that your brain will automatically use that movement pattern even when you are distracted by other factors, such as the ball or other players.
The right prevention exercise program varies from person to person and the exercises listed below may not be appropriate for everyone. Here a few exercises that will help prevent ACL injury:
Single leg RDLs
This is a great exercise to build strength in your glutes and hamstrings. Since it’s performed on one leg, it also helps to improve your balance and stability throughout the leg and core.
Lateral step ups
This exercise builds strength in the quadriceps, glutes, and hamstrings. Similar to the RDL, since it is performed primarily using one leg, it will also help to improve your balance and stability.
Bosu single leg squats
This exercise will primarily challenge your balance and proprioception, with the added benefit of strengthening the quadriceps, glutes, and hamstrings as you perform the squat movement.
Cone taps
This exercise will challenge your balance while also strengthening the glutes and hamstrings through multiple angles.
Bosu lateral jumps
This is a plyometric exercise which involves jumping, landing, and quick changes in direction. Landing on the Bosu ball increases the difficulty as your hips, knees, ankles and core have to work harder to stabilize on the uneven surface.
Single leg box jumps
This is a challenging exercise as it is both a plyometric and strength building exercise. The jump movement builds strength in the quadriceps, hamstrings, glutes, and calves with the added difficulty of stability while landing on the step and absorbing your force as you jump down from the step.
If any of the exercises feel too easy or too hard, there are many ways to progress or regress each of them to make them the appropriate level for you. If you would like guidance on how to personalise a preventative program, book in for an appointment with one of our physios online or by calling 0117 329 2090.