ACL tear

Could the crowding of the sideline on the field could contribute to ACL injuries?

I ran track in college, and my coach would send you home for the day if you pumped to brakes too hard after sprinting. If you decelerate too abruptly it puts way too much stress on your knees.

I see this very often in the NFL. A player is running and goes or gets pushed out of bounds, and within a few feet they are either plowing into the sideline staff or into benches/gatorade tables/etc.

So they do the logical thing and slam their heels into the dirt and go from a full sprint to stopping in a few feet. Any sprinter would be internally screaming from watching this. These players are destroying their knees when they slow down like that. No surprise that the ACLs and MCLs give out so often in the NFL compared to other sports.

Is this an issue that has been brought up before? Why can't they give the sideline's a wider berth, for both player and staff safety? Didn't Wade Phillips get knocked out last year from a player collision? Didn't Reggie Bush tear his ACL on some concrete a few yards from the sideline? And this is only in addition to the aforementioned risk of slowing down from full sprint to zero in just a few steps.

Hey everyone, my latest is on Jimmy G’s ACL injury and specifically the non-contact nature of it (the “classic” mechanism you often see).

For reference, I’m a DPT with my own rehab and athletic development/performance clinic in West LA.

You can find the original on my sports injury blog, TheInjuryInsight.

During , Niners starting QB Jimmy Garoppolo (aka Jimmy G) was scrambling on third and goal when he went to plant his left foot into the ground to take on an incoming defender.

Here’s the video of that moment:

Jimmy G was carted off the field and the medical staff likely performed a hands-on test known as the Lachmann test to test the looseness (laxity) of the ACL:

Based on the testing, the team feared an ACL rupture and those fears on Monday through MRI imaging. The team promptly announced that Jimmy G

After watching the replay, I was pretty sure he had ruptured the ACL. It was the classic mechanism, nearly to a tee, for a non-contact ACL injury. In general, most ACL ruptures happen during a non-contact movement (click , and for more info).

That classic non-contact mechanism for ACL rupture is an unanticipated/reaction cut on an extended (straight) leg followed by adduction (going inwards) and internal rotation (rotating towards midline) of the leg.

Lets go through each phase of that mechanism:

I. Unanticipated/Reaction Cut

Reactionary movement relies on what is known as the neuromuscular system (it’s actually multiple integrated systems). It provides unconscious feedback to your brain about where your body is in space. Through this feedback, muscles are timed and activated to optimize joint stability and promote efficient and effective movement.

The following schematic is a bit heavy (doc) but it’s the cleanest representation I’ve found of the complex neuromuscular system (and believe me, I’ve looked for hours):

If we think of the physical components of the body (muscle, heart, ligaments, etc) as the “hardware”, then the neuromuscular system is part of the “software” that activates the hardware. During reactionary and unanticipated movement, this software has to recognize body position and then maintain joint stability.

As Jimmy G was scrambling out of the pocket towards the sideline, looking for open targets and incoming defenders, and then finally cut towards a defender, his neuromuscular system was in overdrive – dealing with constant reaction movements and integrating all the information coming at it.

That’s a lot of information for any player to deal with but especially for a QB because they don’t train for these unstructured situations (what I refer to as “chaos” training). It’s quite possible his neuromuscular system was overwhelmed and unable to keep up, impairing his knee joint stability during the cut and increasing injury risk (to learn more about the neuromuscular system and it’s relationship to ACL injuries, I wrote ).

To make matters worse, his left leg was planted in an extended (straight) position during that last cut which added a huge risk of injury….

II. Extended (straight) knee during a cut

When the leg is straight like in this picture, the knee joint is at end range. The closer the knee joint is to end range, the more the muscles are in a disadvantaged position and can’t complete one of their key roles – absorbing force. Instead, this force now gets transferred into the joint and into what are known as “passive restraints”, including the knee ligaments.

This is why players are taught to cut and land with bent (soft) knees. In this position, the muscles are able to be shock absorbers and dissipate force. Additionally, because Jimmy G (or any other football player) doesn’t train to cut in this extended knee position, the neuromuscular system is further impaired and unsure of what to do.

This leads to a “point of no return”….

III. Adduction and Internal Rotation

During any high speed inward cut, the plant leg is going to go into some adduction (inwards) and internal rotation (rotating towards midline). That’s natural. However, with an impaired neuromuscular system that can’t recognize joint position quickly and the leg extended which negates shock absorption by muscles, Jimmy’s leg is approaching what is called “a point of no return”:

That “point of no return” is the point at which the knee joint can’t move out of its current trajectory and the ACL experiences a level of stress that’s beyond it’s capacity to tolerate (like the “one more drink” that completely alters the course of the night). At that point, the ACL snaps and the knee buckles:

And here’s the reverse angle which clearly shows Jimmy G looking at the defender and bracing while cutting which speaks to the multi-tasking nature of that final plant and cut movement:

As I said at the start of the piece, Jimmy G was subsequently carted off and his ACL rupture confirmed via MRI.

According to , he will be having ACL reconstruction surgery in the next week or two after the swelling in his knee diminishes. Speaking of surgery…

IV. Jimmy G ACL Surgery

ACL ruptures are one of the most common injuries with upwards of 200,000 per year in the US alone (click , , , , or for more info) so surgeons have it down to an exact science. Here’s one example of how the reconstruction is done (if you’ve read any of my stuff recently, you should be very familiar with this video):

After surgery is completed, Jimmy G begins the long road back…

V. Timeline For Return

On average, NFL players return from an ACL injury in and the outcomes on ACL repair in elite athletes, generally, are very good. has shown that nearly 83% of elite athletes (irregardless of sport) returned to sport following an ACL surgery and most performed comparably to non-injured counterparts.

Further, that early participation and accelerated ACL protocols, like are often used in the NFL, do carry some risk of re-injury. Athletes in accelerated rehab programs may have ongoing abnormal motion and relative weakness for up to 22 months following surgery, in addition to an increased risk for knee arthritis (click and for more info).

Generally, the consensus amongst medical providers I’ve spoken to is the longer the timeline the better – it allows for the ACL graft to heal more and for the player to reduce side to side asymmetries which is a key indicator of injury risk. It would be very prudent of the Niners to let Jimmy G take his time but I expect he’ll be back on the field in nine or ten months, barring any setbacks (the most recent example is Carson Wentz who ).

Once he does get back to the field, what can we expect?

VI. Long-Term Ramifications

There are certainly some long-term consequences after an ACL rupture. Like my NAU professor Dr. Carl DeRosa alway said, “it’s never the same model.”

First and foremost, there’s of re-rupturing the same ACL after surgical repair . It’s no coincidence that . Perhaps even more disconcerting, the risk of rupturing the other side (“contralateral”) ACL after surgical repair is Bio-mechanics, proprioception, and compensation are quite sensitive to injury.

Further, that side to side movement asymmetries (jumping distance, landing distance, mechanics) can exist for up to two years after ACL surgery.

Lastly, there’s potential ramifications for the knee cartilage.

For reference, femur = thigh bone, patella = knee cap, and tibia = shin bone.

After ACL injury, research shows a of knee cartilage and nearly a in developing arthritis compared to an uninjured knee. Arthritis risk is even higher when the original ACL rupture also involves direct damage to the knee cartilage, which may or may not be the case for Jimmy G. Research shows anywhere from an to increase in osteoarthritis risk with this combined injury compared to only an ACL rupture.

To top it all off, we know that kinesphobia (aka fear of movement or re-injury) is one of the last things to dissipate for athletes (click and for more info) returning from ACL ruptures. In other words, one of the last things to return is confidence of movement.

As a Niners fan or just someone concerned for Jimmy G, you might be thinking “oh crap, he’ll never be the same dude”. However, that’s very likely NOT the case.

A specifically looked at NFL QB’s recovering from a torn ACL and it found that 92 percent returned to play with only one re-injuring the ACL and needing a re-repair. Additionally, the study found that these QB’s performed just as well after the ACL injury as they did before AND there was no difference between these QB’s who tore their ACL and their injury free counterparts.

VII. All in all

The reality with an ACL rupture is that it’s always crappy – nearly a year of rehab to get back on the field and potential long-term ramifications thereafter. However, it’s not a death-knell by any means and the great news for Niners and Jimmy G is that QBs often come back at a level commensurate to their pre-injury levels.

Additionally, it’s pretty early in the season so he should be ready to go or almost back by OTAs and, for his mental piece of mind, he’s financially secure after signing that big contract. One major takeaway for Jimmy G is a better understanding of risk/reward – there was no need for him to take on that last defender and it opened him up to all sorts of risk. A very valuable, albeit painful, lesson.

In the meantime, he can keep hitting those photo shoots:

Thanks for reading and until next time. if you liked the piece, subscribe to the email list on the sidebar, join our , and follow us on or to never miss an update.

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You can find the original

Every year near fantasy draft season I see people posting that players coming off an ACL are essentially off their draft boards, and not worth their ADP risk.

Breece Hall tore his ACL the year prior, and ended up being a top 5/10 RB (depending on scoring format) despite not having a great OL and defenses stacking the box.

To anyone who usually avoids these players, does what Breece Hall did this past season make you reconsider players coming off an ACL tear / and or any other season ending injury?

Hi all. I tore my ACL in December playing football and at some point in the next couple of weeks will hopefully be going to a hospital to discuss surgery vs rehab. Curious to know if anyone else has been in the same position and what you did/how it worked out.

I'm a 36 year old guy, a bit overweight but relatively athletic. From what I gather surgery will get my knee back to a better level but takes an age to recover from, by the time I've had it and gone through that I'll likely have missed most the year. Rehab might not get it back to the same level but I'll probably give up on football now, as long as I could play golf and run every now and then I'll be ok.

Wanted to see if anyone had the same injury and what you did and whether it worked or you have any regrets. Obviously every case is different and I'll listen to the doctor's advice but after some general stories.

For some reason this fact kind of blows my mind. The mans durability before and after the injury shows he truly is an iron man.

I work in the sports performance coaching sector, and one of the current thoughts making the rounds in our industry is that many of these non-contact ACL tears are happening on Field Turf (the newer artificial turf with rubber bits embedded in it).

During a game, NFL players are constantly putting their joints in awkward positions outside their normal ranges of motion. When a player makes a sudden change of direction, there are massive forces being produced at abnormal physiological angles. Specifically, smartly commented on the original post about sideline crowding to note that extreme valgus (think of a knock kneed position) is what causes ACL tears. During a cut, if the foot excessively pronates (arch collapses in) it will cause the knee to follow into an awkward angle (valgus). If the force and angle of the movement places sufficient stress on ligaments or tendons, then an injury will occur.

Here is where the Field Turf comes into play. You'll notice that when players make cuts at excessive forces on regular grass, the grass/dirt gives way to create a divot; as a result, the foot and knee are able to recover to less extreme joint positions, and therefore become less likely to place enough stress on the ligament to injure it. However, on Field Turf, the ground doesn't give way. Even worse, it's loaded with rubber, which only serves to rebound the ground impact force back up into the joints, placing even more stress on connective tissue (such as the ACL).

Tl;dr; tell the NFL to get rid of Field Turf and use grass only.

I had a post on the subreddit about my torn ACL that has been removed.

There have been many comments asking how I tore my ACL during a lockdown position and I wanted to write this post to clarify the scenario.

In this picture you can see Craig clamping Lachlan's leg. As you can see, the awkward rotation combined with the severe lockdown flexion can lead to a complete ACL tear.

What I should have done was abandon the chest-to-chest position and move my hips back to relieve the pressure on my knee and clear the lock.

Thank you for all the good wishes in the comments! I didn't think they would mean so much as did :)