Preventing The ACL Injury Epidemic with Strength & Conditioning

I was asked this year point blank at one of my seminars, “What’s the secret to preventing non-contact ACL injuries?” and I honestly didn’t have a definitive answer.

With decades of “research” and prevention programs focusing in on ACL Injuries and Prevention from our industry, we’ve made no ground in systemizing a way to avoid these traumatic injuries, and statistics actually show our “prevention programs” are predisposing the injuries they are supposed to be preventing.

Setting the record straight this week we have Dr. Greg Schaible on JRx showing how prioritizing coaching and old school S&C can be the prevention everyone’s been searching for.

Here’s What You Need To Know…

1. With sky rocketing rates of non-contact ACL injuries in youth and amateur athletics over the past two decades, it’s safe to say that all of our popularized “ACL Prevention” programs aren’t working, and are making things worse.

2. Sure, there are a multitude of statistics to throw at this problem regarding non-contact ACL injuries in female and male athletes, but here’s the deal, weak athletes get hurt more often. No statistics needed.

3. Want to prevent ACL injuries in youth athlete? Lets start with the basics of proper core, hip, knee and foot mechanics in the jump step and change in directions. And yes, these must be executed perfectly to translate into injury prevention.

4. Prioritizing motor control reeducation drills such as depth jumps, single leg jumps and drop step to jump gives athletes the stimulus to create sound biomechanics and the kind of movement that leads to protective physical actions on the field.

5. Putting an emphasis on pure strength movements such as the goblet squat, deadlift, push-up and split squat while ingraining a mastery level execution of these exercises will do more preventative good than any pretend ACL injuries prevention program. You can’t go wrong with strength.

Unfortunately, We ALL Know What ACL Stands for By Now…

ACL injuries have been well documented publicly by the media over the past few years. This extra publicity has brought to light the disturbing frequency of which these injuries occur. More specifically, the number of non-contact ACL injuries which occur. A number of studies have found that 70-75% of ACL injuries sustained are non-conact^1,2.

Contact injuries happen in sports, this is an unavoidable fact. Depending on your sport, the risk for a contact ACL injury can vary significantly. The number of non-contact injuries is much more alarming, because these injuries are much more preventable. We have all seen the athlete who goes to stop on a dime, turn,pivot, or jump and their knee gives out. Next thing you know, you can kiss your fantasy football season goodbye.

In all seriousness, this is not just an issue with pro sports. A large majority of ACL injuries happen every day in high school athletics. Statistics have shown that the prevalence of this injury is much higher in females as opposed to males. It has been reported that females could be 8-9x more likely of sustaining ACL injuries³.

Most of the rehab and performance training world have become well aware of these statistics and have adjusted their treatment and prevention strategies accordingly. That being said, ACL injuries still seem to be on the rise². I believe part of this issue has been the lack of communication from the rehab professionals to properly relay what coaches can do to better prevent this. On the other hand, the coach needs to be willing to possibly change his/her coaching style in some cases. Looking at the pro and collegiate levels, this communication has improved, but resistance still exists.  However, if we truly want to change these statistics we need to start at the source.

Are Youth Coaches The Missing Link In ACL Injury Prevention?

Youth coaches have a very strong impact in the development of an athlete. During the age range from 6–11 years, the body grows at a relatively slow but steady rate, and movement proficiency improves steadily⁴. Knowing this, your next door neighbor’s dad who coaches your daughter’s youth basketball team just became an integral part of the athlete’s long term development.  This then transitions into grade school with the math teacher who coaches the 8th grade basketball team.

While we as rehab professionals and strength coaches like to think we have a large role in preventing ACL injuries, it is the team coaches and parents who have the greatest impact.  Like it or not, most youth athletes do not seek out a rehab professional until after they have already sustained an injury. While the number of youth athletes that seek out a strength and conditioning specialist is higher, this is still a small percentage in the grand scheme of things. So again, it all falls on the coaches and parents who see them the most; yet these are the individuals, who in most cases, are left in the dark.

There are many different areas that could be discussed in ACL prevention such as fatigue levels, previous injuries, excessive practice volumes, or ramping up high intensity practice levels too quickly. While all are very important, I’d rather start with a simple tweak coaches can make that would be very simple to implement and would not require a huge paradigm shift in how coaches run their practice.

Is Strength & Conditioning The Key To Injury Prevention?

As mentioned before, female ACL injury rates are higher than males. Rehab professionals and strength coaches have learned a great deal about potential causes and differences between genders. The largest concern being a significant inward collapse of the knee which happens commonly upon landing from a jump or while changing direction⁵. This is often contributed to lack of motor control and a general level of strength.

How do we best address this issue? A number of people have implemented strength programs and jump training programs as part of an injury prevention program.  This is excellent start! However, your athletes may have a technical flaw that is ruining all your efforts.

Reportedly, females sustain 3x more ACL injuries in basketball than males³. Naturally, basketball is a high risk sport because of the amount of reactive running, jumping, and change of direction which will occur through the course of a game. If you watch closely during a youth basketball game, you will start to notice a very common difference between how a female and male will jump up for a rebound. Males will perform a step through pattern (also known as a penultimate step) prior to jumping. Females will often perform a jump stop prior to jumping. This is also very prominent if you watch a female jumping up to spike a volleyball. Don’t know what I’m talking about, here’s a few examples of correct and incorrect mechanics:

Correct Jumping Mechanics – Step Through / Penultimate Step

Incorrect Jumping Mechanics

Lets Take A Deeper Look At The Movement Patterns

Let me walk you through what is wrong with this faulty jumping pattern. When an athlete sprints forward then performs a jump stop into a vertical jump, there is an immediate change in the application of force from horizontal to vertical. This sudden change in explosive power places a lot of shear stress through the knee and ACL. This shear force is increased the further you see the knee collapse.

Athletically, it is a very inefficient way of transitioning the horizontal force you have created into a vertical jump (vertical force).  It may be the quickest way to change your direction, but it is not the optimal strategy if your goal is to jump as high as possible. The best way to transition horizontal force into the highest vertical jump possible is to perform a step through pattern. This technique is also referred to as the penultimate step. High Jumpers perform this technique better than anyone. Their second to last step is the longest, and the final step is the shortest. This creates a spring board effect that best harnesses all your power into a vertical jump. The pattern should be performed no matter if jumping off of two feet or jumping off of one foot.

This jumping pattern can also be noticed to a lesser extent during a jump shot. When a boy is taught how to shoot a basketball, often they will be taught a step to pattern for a jump shot. Girls on the other hand, frequently perform a jump stop before shooting a basketball. A step to technique should be emphasized when teaching a jump shot. A step to pattern will again transfer any forward momentum into vertical momentum much more efficiently than a jump stop.

The video below demonstrates a step to pattern where force is transitioned from my left foot/leg into both legs. The video then shows a jump stop prior to shooting the basketball. As you will notice, it is a much more abrupt stop. This abrupt stop is often why you will see the knees collapse inward more frequently, because the body has more force to absorb over a shorter period of time.

Step To Pattern

Watch closely at a middle school or high school girls basketball game, and you will notice this happening all the time. Most girls will perform a jump stop prior to shooting a basketball as a method to get the ball to the rim and overcome generalized upper body weakness. Now let me clarify, that I am not trying to tell a coach to never teach a player how to perform a jump stop. I realize a jump stop can be very advantageous for the offensive player at times during a basketball game. I’m simply suggesting that when teaching kids how to play basketball, first teach the athlete how to jump properly utilizing a step through pattern and a step to pattern for a jump shot. Once these have been perfected, then teach them how to control a jump stop. This way, they only use it when necessary and have the body awareness to control the movement.

If you ignore these movement patterns, chances are after numerous jump shots, practices, and games these faulty movement patterns are then engrained into their body’s habits. Next thing you know, the same pattern starts to form in other sports. Interestingly, one study found that ACL tears during volleyball are much less common². I would argue that volleyball is not as dynamic of a sport as basketball. It is slower paced and less fatigue takes place. However, again, if you watch a female youth athlete jump up to spike a volleyball, chances are you still see them perform a jump stop prior to jumping vertical to hit the volleyball.

Many females will play both volleyball and basketball. While volleyball may not be as aggressive, there is still a lot of jumping which takes place. Isn’t it possible that if not addressed these poor jumping mechanics will translate into a basketball game where the risk for injury is much higher?

This technical error should be corrected immediately, and better yet, never be taught. Think about how many times an athlete will jump during the course of a season in sports such as basketball, volleyball, and even soccer.

The Progression of ACL Prehabilitation – Jump Mechanics

Just like in training, technique should be addressed first. We need to be careful about applying speed, power, and explosiveness on dysfunctional movement patterns. A proper youth training program should focus on both technique and general strength.

First, teach the athlete how to properly sequence a jump. This is important for skill acquisition. Here are some drills to perform that will help develop a step to or step through pattern. While performing these exercises, have the athlete pay close attention during takeoffs and landings, that the knee does not collapse inward.

Drop Jump Mechanics

Coaching Points: 

Find a box that comes up to your kneecap or one that is appropriate to skill level. Step off the box landing on both feet equally and softly as possible. Knees should stay in line with your middle toe upon landing.

Single Leg Box Jumps

Coaching Points:

Find a box that comes up to your kneecap or one that is appropriate to skill level. Explode off of one leg, and land on the opposite foot as softly as possible. Knee should stay in line with your middle toe upon landing.

Drop Step To Box Jump

Coaching Points: 

Find a box that is appropriate to skill level. While facing sideways to the box, perform a quarter turn by first moving your inside foot followed by the outside foot. Explode up to the box, land under control with both knees in line with your middle toe.

General Box Jump Coaching Points

The box height should be about knee height, but ultimately up to skill level and what you are able to perform in a technically sound manner. Repetitions should be kept low so the athlete can focus on power development and proper technique.  3-5 sets of 2-5 reps is a good place to start.

Primary Strength Work To Prevent ACL Injuries

A baseline level of strength should also be developed to withstand these forces during sporting events. Focus on proper technique and proper knee control. The knee should stay in line with the athlete’s middle toe. Goblet squat, DB deadlift, SL deadlift, FFESS are all good options.

Goblet Squat

Coaching Points: 

Grip the dumbbell tightly and hold against your chest. Feel your entire foot as you sit down between both legs. Keep knees in line with toes and chest up proud.

Dumbbell Deadlift

Coaching Points: 

The dumbell will start directly underneath the body. Push your butt back and chest up proud. Grip the dumbbell and drive through both legs to stand up tall.

Dumbbell Single Leg Romanian Deadlift (RDL)

Coaching Points: 

Soft knee bend. Reach as far backwards as you can with your heel. Your body should create a nice straight line from your heel to your head.

Front Foot Elevated Split Squat

Coaching Points: 

Get in a split stance position with one foot up on a 6”-8” block. Lean your upper body slightly forward to feel your front foot. Drop hips down toward the floor and drive through your front foot to stand back up tall.

General Strength Coaching Points

Sets/Repetitions at an early age should be higher for skill acquisition and general strength gains. 3-4 sets of 8-12 reps is a good place to start.

Upper body exercises are also important for a number of different reasons. In youth athletes, females more so than males, this will help develop a jump shot without needing as much leg power. Inclined pushups and DB floor press are great options.

Incline Push-Up

Coaching Points:

With your hands shoulder width apart and your core and glutes engaged, lower your chest down to the bar under control and dynamically push back up off the bar.  Keep your body in perfect alignment during the movement and hold the pillar strong and stable.

Dumbbell Floor Press

Coaching Points: 

While on your back, bring your knees up with feet flat on the ground allowing your lower back to drive into the ground. You will slowly control the dumbbells down as your elbows make smooth contact with the ground. From that position, drive up the dumbbells directly over the shoulders. For parameters, 3-4 sets of 8-12 reps will work here as well.

About The Author

Dr. Greg Schaible is a physical therapist and strength coach specializing in athletic performance.  He attended The University of Findlay as a Student Athlete.  As an athlete he competed in both Indoor and Outdoor Track & Field where he earned honors as a 5x Division II All-American and a 6x Division II Academic All-American. In 2013 he completed Graduate School earning his Doctorate of Physical Therapy (DPT).  Greg is the owner of On Track PT and Performance. In addition to his rehabilitation services, Greg has a passion for sport specific youth athlete training. Follow On Track PT and Performance on Facebook at On Track Performance.

References

1. Boden BP, Dean GS, Feagin JA, Jr, Garrett WE., Jr Mechanisms of anterior cruciate ligament injury.Orthopedics. 2000;23:573–578.

2. LaBella, Cynthia R., et al. “Anterior cruciate ligament injuries: diagnosis, treatment, and prevention.” Pediatrics 133.5 (2014): e1437-e1450.

3. Prodromos, Chadwick C., et al. “A meta-analysis of the incidence of anterior cruciate ligament tears as a function of gender, sport, and a knee injury–reduction regimen.” Arthroscopy: The Journal of Arthroscopic & Related Surgery 23.12 (2007): 1320-1325.

4. Kinanthropometry. JAP Day, ed. Champaign, IL: Human Kinetics; 29-43, 1986.

5. Malina, RM and Beunen, G. Matching opponents in youth sports, in: The Child and Adolescent Athlete. O Bar-Or, ed. Oxford, England: Blackwell Science, Ltd; 202-213, 1996.

6. Hewett, Timothy E., Joseph S. Torg, and Barry P. Boden. “Video analysis of trunk and knee motion during non-contact anterior cruciate ligament injury in female athletes: lateral trunk and knee abduction motion are combined components of the injury mechanism.” British journal of sports medicine 43.6 (2009): 417-422.