Why Drake Johnson is susceptible to ACL tears
So, I was bored this afternoon and decided to watch some games from last year and I made an observation, which some of you may be interested in, others maybe not. But, Drake Johnson has obviously torn his ACL twice and I think I know why.
Before I get into why Drake’s susceptible lets do a quick anatomy lesson. Your ACL attaches to your femur (upper leg) and tibia (lower leg) and is one of the major ligaments (attaches bone to bone) that cross your knee. Its role is to prevent your tibia from rotating independently of your femur. To illustrate, cross your right middle finger over your index finger. This is a model of how your ACL crosses over your knee joint. Next wrap your left hand around your crossed fingers and externally rotate your right hand. You’ll notice this force tightens your fingers. If instead you internally rotate your right hand, your fingers loosen and come apart. The former is a stable position for your knee, the latter an unstable one. When your feet are pointed straight ahead of your body/torso and your knees are slightly outside of your feet you are creating a stable ACL. When your feet open up it becomes difficult to track your knee outside unless your have incredible glute control and your tend to internally rotate or collapse your knee, collapse at the ankle, and lose the arch in your foot.
It looks like Drake wears ankle supports, which is a possible indication that he’s been doing this for some time. The arch you won’t see in a fully padded football player wearing cleats, but the knee you certainly can. I believe this latter foot/knee position is exactly what I see Drake doing and why he is susceptible to ACL tears and he’s allowing his feet to externally rotate which is driving his knee inward and losing torque at his knee joint and making his ACL susceptible when under high speeds/loads. But, this all starts by losing force through the hips. Here’s a few pictures that illustrates what I mean.
Notice the knee internally rotated and inside the foot and the ankle collapsing
Again here, foot externally rotated and knee internally rotated.
Again, same thing
Drake uses this strategy over and over. The vast majority of the time it is not an issue as he's obviously a high level athlete and a very strong guy. However, when he uses this strategy under high loads or speeds the ACL becomes more susceptible and eventually as his past has show will tear under the pressure. If he can learn the maintain torque through the hip, knee, ankle, and foot by pointing his toes straight ahead of him, not allowing his arch to collapse, and tracking his knee over or slightly outside of his foot, the will greatly reduce the chances of this happening.
But I followed your instructions to cross my hand over my crossed fingers, and that seems to make sense. Very nice post
Are you Barwis?
I appreciate the time you've put in to this but as inappropriate as I can be in my post sometimes I feel like this is over the top. Mostly because if you ever played sports and had a major soft tissue injury you'd realize that the inertia and force that can cause an injury like this can be random. Maybe you were being tackled and maybe you weren't. I beileve its more of a cumulative effect on the joint along with other factors more than anything which is actually kinda in alignment with your assertions.
When I had my achilles repaired after a complete tear and asked my othopedic surgeon who was the Ortho surgeon for the Cal AD at the time what he thought, he said "I tore mine taking out the trash one day". Athletes in high impact sports are more succeptable but if you're active it can happen to anyone.
Lets let him get healthy and just enjoy his time as a UM student and Football player without critiquing his injuries.
Have you ever tried to "cut hard" with your femur internally roated, your tibia externally roated and your ankle pronated?
Uhh...maybe?
Every day, bro. Every day.
A few pionts. One, Drake's first tear was against Central Michigan in 2013. I don't recall that one. His second one however was last year against OSU and although there was contact it didn't appear to impact the injury. The injury appeared to occur due to the motor pattern described above.
Every circumstance is different and there could certainly be other factors involved. However, this faulty motor program is without a doubt part of the problem IMO. FWIW it's very common for middle aged men to tear their achilles playing pick up basketball for instance. This is probably because we don't realize what our body is doing while we're doing it and lack the motor control and/or awareness to prevent it.
I'm sorry if you took offense to the topic. This was merely an exercise in biomechanics about a relevant football player that I tought folks might be interested in. It's not intended to be negative towards him. Analyzing human movment is simply what I do and is my educational background so take it for what it's worth.
Like I said I appreciate your perspective. I'm really only taking fault with you critiquing a current student athlete's affliction, he is trying to rehabilitate after two major injuries, and could potentially be the end of his athletic collegiate career. It takes a lot of determination and effort to get back to earning a place on the roster not to mention just being able to not walk without a limp especially when he's middle aged. I personally just don't think its fodder for internet fans of the sport and team regardless of your medical background.
I'm sure he's getting the best care available and don't think that any of Your patients would benefit from a posting of "how to not tear your ACL" courtesy of so and so, bouught to you by "poor mechanics" who's trying to rehab right now! I certainly wouldn't want you making any prognosis while you were bored. Medicine is about the patients and not the cure.
Again, I don't think your op intent was malicious in any way. I just hope this doesn't become a trend here. I've had several soft tissue injuries myself and I know how even after rehabilitation they can affect your lifestyle and experience, so its a touchy subject. HIPPA is the law of the land for a reason though, even if not for collegiate athletes. Rant ova!
on the level and effects of Jason Pierre-Paul's finger injuries and his chances of playing? I think this is a well thought out and prepared observation of a potential cause. He's not speculating on comebacks or future injuries. He's saying, in his opinion, he needs to look at a few things to lessen the chances of future injuries. I don't see how this is different from the coaches on the board giving their opinions on how a young man will develop.
I iappreciate the infromation.
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I was watching last year's games and it just occurred to me and I guess I didn't consider that some may take it negatively. Although my hunch is the topic becomes a little less interesting once the ahtlete graduates if I were to wait. I guess I could have brought up other athletes from years past, but that wasn't really the point of what I saw.
I do understand and appreciate the work that goes into rehad and the lingering affects it can cause. I am a former college baseball player and I have also had a number of injuries during my playing days including a bimalleolar transverse fracture, which basically means I shattered both bones in my ankle. I had 3 surgeries and was no weight bearing for 4 months and I still do regular soft tissue work and mobility drills to try and maintain normal function in the ankle and I'm 36 years old. I have no doubt I will be dealing with the lingering affects of this injury the rest of my life.
I guess my point is that analyzing why an injury occured IMO doesn't take away or from the work required to rehab it nor the discomfort you have to endure with it. The two are mutually exclusive IMO. It's more matter of fact and is just an interesting analysis IMO. I do believe in today's information age that conversations like these may make these injuries occur less often through awareness and education. Not that I think my little post will do that, but that it may contribute in some small way that makes this information more accessible to those wihtout the background knowledge in the subject.
a running back scoring two touchdowns!!! those are different touchdowns, no?
Did anyone besides me read this post and start humming: The ankle bone connected to the shin bone, the shin bone connected to the thigh bone...??
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I appreciate the mechanics discussion, and I don't want to be condescending, but there are a few well defined risk factors for ACL tears. These are implicated in an increased incidence of adolescent females tearing their ACL compared to their male counterparts. These scientifically validated reasons include diminished ratio of hamstrings strength to quad strength and anatomy of the intercondylar femoral notch in females (smaller than males). This is obviously not Drake's problem...
non-contact ACL-tears like Drake's are the norm and are more common in people who have had an ACL reconstructed previously, so not totally surprising....
People are different in now much rotation exists in their femur and tibia and how much their toes point out when they walk. (duck foot vs pigeon toed) that has never been shown to affect their likelihood of tearing their ACL
Long story short... Go on Drake. Keep up the good rehab and kill it this fall
Dr Vorax
I was about to say... did OP just watch Khan Academy on the anatomy of the knee or something?
What possibly spurred this thread LOL
I love it tho don't get me wrong.
Certainly they are a somewhat common injury and you are correct in that having a previous ACL reconstruction does place one at higher risk for re-injury. Yes, athletes are likely at higher risk for injury of the ACL due to monsterous joint reaction forces caused by large magnitude, multi-planar accelerations and decelerations, but the risk for non-contact ligamentous damage can be increased with improper hip loading resulting in the knee valgus/tibial external rotation fault noted with lateral cutting. Derrick Rose is another athlete which demonstrates this dysfunctional mechanic and likely contributes to his nagging knee issues which have plagued him since his initial tear. The ankle can play a part in the mechanics of the leg, but even more important is motor control of the hip in the context of football movements. I see this all the time as a PT where a movement can be strong statically and dynamically in the clinic, but once on the field, old motor planning takes over and similar dysfunction is observed placing him/her at risk for reinjury. Movement patterns are learned over many years and can be difficult to re-train. The success of therapy can hinge on whether or not there is adequate carryover from clinic to field.
Dr. Erik
There are many risk factors, not the least of which is previous injury. It’s worth noting there is a difference between a risk factor and a mechanism of injury. Many of these risk factors, with the exception of neuromuscular control, have the same outcome on osteokinematics…an internally rotated knee (valgus) and landing with a low knee flexion angle (too straight). At first sight I focused on the former, but I think both are probably happening here.
There was a good review of literature in 2012 in The Journal of Strength and Conditioning Research on mechanisms of non-contact ACL injury. There is a body of research on kinematics using video analysis combined with retrospective surveys that suggest low knee flexion angles, knee joint rotation, and valgus collapse as a culprit in ACL injury. There are also several studies that adopted a descriptive epidemiological video analysis method that had similar outcomes including one with minimal knee rotation. There are also a number of cadaveric studies that show ACL strain or anterior tibial translation increased with low flexion angles combined with valgus stress. And, there's an MRI study I’m familiar with that revealed impingement of the ACL against the lateral wall of the intercondylar notch can occur with external rotation which combined with valgus movement, elongates the ligament putting it at greater risk of rupture. In addition, research suggests that anterior tibial translation is greater when the knee joint is moved through the kinematic and kinetic extremes believed to stress the ACL, highlighting the importance of knee joint stability for dynamic tasks for preventing noncontact ACL injury.
One problem with some of the studies on knee joint stability as a mechanism of injury is they typically only measure stability in a passive state. I’m not aware of any research that has actually shown that passive stability correlates with dynamic stability. Also, it assumes passive knee joint stability is a sufficient measure of dynamic knee joint stability. The research fails to find cause and affect relationships, rather it simply notes a higher incidence in experimental cohorts. Now that doesn’t mean it’s not happening, but it leaves room to question and suggests more research is needed, which is the beauty of science why I have provided merely a theory of why I think Drake is at increased risk.
BTW I’d be happy to provide any of the citations if you’re interested.
thanks MgoStrength,
it's obvious that you have thought a great deal about the subject and are not at all defensive regarding differing opinions like others who feel the need to flex their credentials on the blog.
I guess the difference in our opinions stems from your conjecture (which you rightly acknowledge is theory (no disrespect)) vs what I was trying to highlight as peer reviewed evidence. maybe part of the disconnect is the difference in terminology used in our fields. as orthopaedic surgeons we refer to valgus as an increase in the tibiofemoral angle (or amount of knock-knee) not the rotation of one bone relative to the other.
Ashish Bedi (U-M orthopaedic surgeon) studied hip rotation contributing to ACL tears, and found an increased incidence of injury with restricted hip motion, but this was in relation to femoroacetabular impingement and differences in pivot landing (not how he injured his ACL). something that we have no reason to believe that Drake Johnson suffers.
Moreover, many of the in vitro tests of ACL failure study fatigue failure vs catastrophic failure which is the likely mode of failure in live human subjects.
In addition, as you note, there are differences between studies of passive stability vs dynamic stability and which better represents real-life events. In the end, both of our fields have their own ideas regarding why people tear their ACL. both of us are probably right (and wrong) to some degree)
Here are some recent orthopaedic reviews regarding risk factors for ACL tears...
Risk Factors for Anterior Cruciate Ligament Injury
No worries, it's all a part of the discussion, which hopefully sheds light on the subject, may help multiple minds re-think things, or at the very least is an interesting relevant intellectual discussion. Thanks for adding in some literature and I will take a look and let you know what I think. Regarding credentials, yes we are often proud of ours. I have a graduate degree in exercise science with a concentration in performance enhancement and injury prevention and am quite used to supporting my stance with peer reviewed literature. While a certain degree can let others know of pre-requesite knoweledge, it doesn't prevent those without it from having relevant information, so I try not to push it unless questioned. Plus, there are lots of well educated folks on this board that you may never realize until they told you. And, I have had many good discussions with people with very little formal education. As long as you have an intellectual curiosity, are willing to provide evidence to support your view, and don't mind others asking questions, then it's all good.
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The way I saw that injury occur, Drake tried to make a sharp cut at high speed and put too much internal lateral force on his knee. The abductors that push the leg out to the side are stronger than the adductors that pull the leg in. What happened to Drake seemed like what happens when you catch an inside edge in skiing.
Gale Sayers used to make cuts like that, and it caught up with him. Barry Sanders and Marshawn Lynch run with a wide stance, and most of their change of direction involved loading the outside of the knee, that is structured for high lateral loads.
Drake has guts, and he runs with abandon. No doubt he's doing a lot of lateral leg movement rehab using therapy bands. I hope he learns to moderate the stress he puts on the inside of his knee.
I had a medial collateral ligament strain in football. Sometimes those things never come back 100%. I had to stop playing racquetball, which inevitably overloads the inside of the knee. Basketball and skiing were still okay.
Godspeed Drake. Comeback strong!
What you pointed out with those pictures indicates a tight Soleus, the inside of the calf. Trigger poinst release and strengthening the Gastronemius and Gluteus Medius could help.
Blake Griffin had a Strength and Conditioning coach who found he had similar biomechanics when he first came into the league, and took corrective measures. Seems like it worked okay for him.
I was watching the Florida capital one win yesterday on B1G and that 20 jersey cutting down the field looked top notch. I see a lot of Hart in the way Drake cuts.
Interesting write up. What would make it more compelling is if you posted pictures of running backs not displaying the issues you describe. Something that allows visual comparison.
...it's hard to imagine any running back "using a strategy" for running. They run naturally, the way they feel most comfortable running. I'm not sure one can "learn" to run another way and consciously point their toes while dodging linebackers.
Everyone is a bit different. Some RBs run high and fast like sprinters (I think of Eric Dickerson or Robert Smith) and some run low and hard (I think of Peyton Hillis or Brandon Jacobs).
I think ACL tears are more a result of torque resulting from quick change of direction that puts tremendous strain on the joints rather than pure running technique. Some athletes may have stronger knees and tendon flexibility than others.
Respectfully, I must disagree. If you're running track, you can enhance a bit, but everyone runs differently. Gate, style, etc... remain unique to the individual, IMHO.
Kinda like the golf swing. You can try to emulate Niklaus, Mickelson or Woods, but at the end of the day, your swing is yours and yours alone. You can enhance aspects of it, but not to the point where it changes that dramatically.
If one is pigeon-toed, a supinator or a pronator, you're stuck with that. Orthotics may help to a limited degree.
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They certainly do, but that is what coaches do, correct technical flaws. Now, it's a bit of a gray area, who would cover this particular area. If you want to go waay back, PE teachers in grade school instruct fundamental movement skills, but let's be honest, how many really correct them when they are faulty or have a good understanding of them? An offensive line coach would instruct a lineman to get his pad level or hips down if he's too upright and a RB coach would do the same. A good strength coach should be able to spot these things, but lets say they do, is there really time in their day to address every individual athlete in this manner and create a program of interventions to fix the issue?...in my experience as a strength coach, no. Is it the medical staff's job?
S&C workouts certainly perform drills on footwork, deceleration/acceleration mechanics, change of direction mechanics, landing mechanics, etc. Also, his rehab would include this from the previous injury. But, some research suggests while it's pretty easy to correct passive movement flaws in isolation, it's much more difficult to do so in competition or under stress and/or high speeds. It's very difficult to change old motor habits. So, while every athlete may run differently, they should be aware of how that style impacts their risk of injury, especially one that has already gone through an injury and rehab IMO.
This was really interesting. I mentioned it to my wife as an example of cool things on MGoBlog, and she knew about this problem from some experience she has with ballet, where the problem is called "turn out" and is to be avoided for the sake of one's knees: "you do a lot of pointing your toes out and if you don't keep your knees over your toes, you'll screw up your knees. ...it probably looks stupid, too."
Was this is pretty cool, thx!
I did the middle finger - index finger thing and twisted as instructed, and broke both of my fingers. Thanks, OP. Thanks a lot.
Please excuse typos - written with my nose - because of the OP.
He is succeptible to ACL tears because he is our best running back right now and we can't have nice things.
Nice. You should do a writeup that explains why when I drink a bunch, I think quesadillas are delicious.
Because they are.
/end writeup
Weird that he is known as a speed guy in high school though (excellent hurdler...one of the better in the entire Midwest if I remember correctly) and his form /stride is so "off".
Anyway...great illustration on the last pic of his externally rotated foot and internally rotated knee.
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His problem likely won't show up in linear running (straight ahead) unless it involves a fast stop and re-start. It is much more likely to rear its ugly head in change of direction or landing.
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