Movement Thread:
@FFStudentDoc started a conversation about Jerry Jeudy's unique knee mechanics and possible injury risk.

Whether he is at risk or not is tough to measure, and these characteristics are actually how he wins. https://twitter.com/FBInjuryDoc/status/1227037998866288641

Jeudy displays laxity in his knees that produces a "valgus" mechanism, meaning his knee collapses inward.

This distinct pattern shows up constantly. It's simply part of who he is.

The concern here is that dynamic knee valgus is associated with ACL tears.

While many ACL ruptures occur with this motion, the research is mixed on the relevance of knee valgus as a risk factor. Many athletes enter these positions or have predispositions to it and do not suffer a tear.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6088120/

In fact, many athletes explode by way of their knee valgus. The laxity they create through their hip/knee/ankle complex also allows them to create fluid deceptive movements.
You might recognize these guys.

The valgus gives them different access to quads/glutes to create power.

Accessing knee valgus is a valuable ability that makes reading the hips more difficult for the defender and allows the athlete to create more lateral power. https://twitter.com/sidelinehustle/status/1113572687090266112

You don't have to look far to find another effective valgus WR. Calvin Ridley's knees look a lot like Jeudy's. This slippery mover often operates in valgus.

Jeudy and Amari use their knee valgus to sell angles more aggressively. While other athletes need to square up to create lateral displacement, they can sell hips outside until last possible moment.

This is precisely why his routes and jukes are so violent.

There is no correlation shown btwn observed dynamic valgus during a vertical drop test and ACL risk.

But your therapist will tell you to avoid valgus position during jumping/squatting.

Athletes adapt around their anatomy, and they build strength on top of their mechanics.

Edwin cited an article from @GregLehman stating that even though training/prehab reduces risk, biomechanical patterns don't change. The question remains: how much do mechanics matter if the athlete has created dynamic strength around their pattern?

http://www.greglehman.ca/blog/2017/9/19/when-biomechanics-matters

Injury occurs when load exceeds capacity.

Knee valgus and ACL risk are difficult to connect bc athletes adapt around to their anatomy. Jeudy's body has found a way to support his knee consistently & repeatedly. He has developed the capacity to absorb loads that others do not.

In my experience, the risk is amplified when another injury in the kinetic chain disrupts the typical pattern of support.

An injury alters the neurological firing patterns, and thus the compensating support mechanisms for a "risky" mechanic are no longer there.

This also occurs in athletes with or without anatomical valgus patterns:

Dalvin struggled w/ a hamstring his last yr of college.
Guice an ankle.
Edelman: broke his right foot twice
Klay: playing on a bum hammy.
Fuller: recovering from a groin injury.

When surrounding tissues cannot support the same way, the risk is amplified.

If the foot sticks a bit longer in the ground, they overstride, don't flex enough, or the firing pattern from their hip or ankle delays/isn't as strong, then they don't absorb the force the same way.

From a scientific perspective, when an at-risk athlete suffers multiple or nagging lower extrem injuries, I'll activate #ACLwatch.

In the end though, safe/unsafe is different for each body. Measuring risk for an individual is more of a theoretical exercise.

If Jeudy walked into my lab, I'd be tempted to play with creating power from a different position, but would I tell Jordan to avoid bringing his knees together during a dunk?

If someone is special, you don't want to take away the pattern they've built or tell them it's "risky."

From a fantasy perspective, everyone gets hurt, even bow-legged athletes like Edelman or Guice.

Instead of delving into hypotheticals, just fade Jeudy cuz his dominator rating doesn't meet your threshold and that's way riskier amirite, my nerd friends?