If you talk to high school athletes, they can all name at least one person they know who has suffered a knee injury. If it seems like more of these athletes are female than male, that is because females are at a much higher risk for knee injury.
-Female athletes are 8x more likely to tear their ACL than their male counterparts
-As many as 70% of ACL injuries involve little or no contact with the other player
-1 in 50 female high school athletes sustain a knee injury
-Rate of noncontact ACL injuries in soccer is twice as high in females than in males, and in basketball, nearly four times that of males
There’s been a big misconception that ACL injuries result from direct contact. In reality, less than 1/3 of all ACL injuries result from direct contact. That means over 2/3 of injuries come from other factors. These are related to:
-One step acceleration/deceleration
-Sudden change in direction
-Landing from a jump with inadequate knee or hip flexion (at or near full extension)
Why they occur more frequently in females than males:
There’s a few theories out there worth really looking at:
-Wider Pelvis and Knee Alignment (valgus)
A wider pelvis leads to a greater Q angle (quadriceps angle; where the femur meets the tibia) in women than men. A large Q angle puts increasing force on the ACL each time the knee twists. While a twisting injury in men may only stretch the ACL, that same motion creates more force rupturing the ligament in women. Women are also known to have a knock kneed alignment. This alignment tends to have women have their knees inward when they land predisposing them to injury.
-Lax ligaments and hormonal differences
Women have more flexible ligaments (especially at the time of their menstrual cycle). This can be good to prevent other injuries but in the case of the knee, normal stresses are transferred over the ACL, making the ligament making it more prone to rupture.
-Quad to hamstring ratio
Females are well known for having stronger quads than hamstrings. If the hamstring cannot balance the power of the quadriceps, the imbalance can cause the tibia to slide forward causing significant stress to the ACL, leading to injury.
-Flat Footed Landing
Just like above, where the hamstring needs to balance out the quad to prevent the knee from moving, the same needs to happen with the calf muscle. Landing flat footed (compared to on the balls on your feet) doesn’t allow your calf muscle to absorb the force, leading to the knee buckling and ACL tearing.
What can we do about it?
CONTROL THE CONTROL-ABLES. This is one of my favorite sayings and certainly applies here. While you can’t control things like hip width and knee valgus, you can control learning to properly jump, land, accelerate and decelerate. You can train single leg movements and develop the strength of your hamstrings. You can be proactive to avoid time spent on the sidelines and maximize time spent training and developing.
-Proper leg strength training & core training
-Proper neuromuscular (balance and speed) training
-Proper coaching on jumping and landing (and avoiding any straight knee landing)
Here are 5 exercises you can use towards prevention:
1. Air Squats
(3 sets of 10 reps)
-Feet shoulder width apart
-Hips push back first then down
-Knees follow over the toes
-Feet stay flat and chest stays up
2. Jump Squats
(3 sets of 8 reps)
-Feet shoulder width apart
-Load into your squat and jump up as high as possible
-Land soft with knees bent and aligned over the toes
3. Lateral Bound (with a pause in the landing)
(3 sets of 10 reps)
-Start balancing on one leg
-Make sure the knee is bent and aligned over the toes
-Hop 2-3 feet laterally and land soft with knee bent and hip, knee and toes all aligned
-Hold the landing for 3-4 seconds to show control
4. RDL (Romanian Deadlift)
(3 sets of 12 reps)
-Hold the barbell (or dummbells) at hip level
-Move the bar down by pushing your butt back first
-Keep the bar close to the body, head up and shoulders back
-Lower the bar to just above the knee
-Drive the hips forward to stand up tall
5. Medicine Ball Lateral Throws
(3 sets of 5 reps each side)
-Start with feet hip width apart
-Explosively rotate through the core and throw the med ball at the wall
-Maintain tight abs and a stable bottom position
-Receive the ball and continuously repeat
The best prevention is being proactive. The less time a player is spent on the sidelines injured, the more opportunity they have to progress and develop. One day a week is enough to make a difference!
 National Institutes of Health Medicine Plus. An Athlete's Nightmare: Tearing the ACL.
 Barber-Westin SD, Noyes FR, Galloway M. Jump-land characteristics and muscle-strength development in young athletes: a gender comparison of 1140 athletes 9 to 17 years of age. Am J Sprts Med.
 Beynnon BD, et al. The effects of level of competition, sport, and sex on the incidence of first-time noncontact anterior cruciate ligament injury. Amer J Sports Med, August 2014;42:1806-1812.