How do you assess a patient to see if they have a leg length discrepancy? If they do, what could it mean exactly? (Is it an instability in the hip, a muscle locked short or long, etc) If it is not a true LLD, would you attempt to fix it? If so, what would you do? Lastly, do you think trainers should be looking at this before we begin a session and trying to fix it?

There are probably a couple ways to measure leg length, but the valid by my standards (I don’t know what the literature says) is this.
Tape measure from ASIS to medial malleolus.
For better at least intra-rater reliability, I would suggest thumbing up from underneath the bony landmarks, and measure from where the button starts to jut out. This way you can have a good shot at measuring the same way every single time.

I'm saying medial malleolus to ASIS

You can measure standing bilaterally, standing on 1 leg, and then laying down in the both positions also.
If there is a consistency, then there is really a leg length difference. If there is a difference standing vs. unloaded, it’s a muscular tension somewhere.

If it is a very real structural difference, the shoe can be built up.  Or you can have an osteotomy somewhere if you want.  That might not be preferrable though.
If it’s a muscular dysfunction, it can/should be fixed.

I would say you probably don’t need to be looking at it, especially at first, because if it’s real, I’ve got to think the person already knows. If it’s functional, it will come out in the wash with the FMS asymmetry.
I typically discard anyone that tells me they have a leg length discrepancy especially from another clincian. It’s part arrogance on my part, and part I know the reality that it will come out as we go through the movement screening and assessment. Leg length itself is a Test. It doesn’t tell me enough.

I think the key here is this.  Always look at dynamic patterns first.  If the person moves well, that is all we care about in the first place.  If there are major problems or asymmetries that show up, they should be addressed.  Tag out if you have to.
But static postural tests and exams should only come after movement has been exposed to be in error.

Like most things, leg length should come out in the wash.

Recently…attended a [student] seminar put on………..who could come up with the best rehab program for a complete ACL tear in a female basketball player . The three teams were to present on the specif surgery that would be done and how they would handle the case. One of the common themes amongst every one was the use of isometric hip adduction while performing dynamic squats. Essentially they recommended performing a squat while squeezing a ball between there legs.

Good for ACL rehab according to the "literature." Thanks, APTA!!!

This is very foolish and old school.

1) The dated research that links ADDuctor isotonics to VMO cross-sectional area was 1) studied with open-chain movements, and 2) I believe was second to poor soft tissue quality in regards to binding of the ADDuctor Longus to the VM and VMO. That poor soft tissue quality is likely what led to the injury in the first place that warranted a belief for VMO attention.

Keep in mind that the VMO is a player in PF stability, as all knee structures are, however, it’s dysfunction is 100% reactive. A healthy neuromuscular system marked by centration never has a deficient VMO. Focusing on training it up is benign at best.  It is inhibited as a part of pain/injury/threat and recovery there of, while other muscles like the ADDuctors and RF become facilitated. Releasing or relieving the reasons for facilitated tone is the answer for restoring the VMO, not investigated local approaches. This does not work.
The VMO is not the problem before injury, and it is not the problem after injury. It is just the expression to get you to stop hurting yourself.
I mean is there anyone without an old school physical therapy or bodybuilding background that even still talks about the VMO?

It's like building up the floor without worrying about the roof.

2) If you aggressively ADDuct with something in between your knees and feet apart, try to visualize where the femur and midfoot would “want” to go if you removed the ball or pillow. You are cranking into valgus collapse, but there is an illusion of alignment because of the ball in between the knees. This is just straight out dumb.
We know in fact, we should probably be doing the opposite, banding the knees and demanding the valgus collapse be reacted to and met with femoral external rotation and mid-foot rotation.

There are times in which activating the ADDuctors in an effort to prime the core to stabilize prior to a pattern is useful. This hopefully temporary use of a high threshold strategy is supported by the Superficial and Deep Front Lines of Thomas Myers’ Anatomy Trains, mainly he Deep. The ADDuctors have concurrent neurological pathways through the fascia with many of the abdominals, so there is irradiation as a result.
However, in a technique such as the Toe Touch Progression in the FM System, the feet are as close together as possible to create a bony block against pronation and further valgus collapse. This brief approach is also used sparingly, and is reloaded with glute activation as soon as the hip hinge is satisfactory.

Maybe interested in pre- and post-VMO EMG with this…………….

3) Researching concurrent ADDuctor and glute medius activation is not interesting to me. It is typical contrarian nonsense to try to be a renegade and prove everybody wrong. Not everybody needs to be Galileo.
More importantly than that, the laws of reciprocal inhibition will dominate such a study, and dumb people will look at the research and make some silly attempt to rekindle ADDuctor isotonics just because they are “dimmed” when the glute medius is heavily activated.  In fact, we would want the opposite.  Luckily, this notion hasn’t really fallen into the hands of the Champions of the Stupid as much as some other things.
Just make the move look right and have good underlying mobility and stability. Don’t try to reinvent the wheel.  A centrated hip joint will have comparable muscle activation around all aspects of the joint.  A big EMG isn’t always a good one.
And how or why this equates to the VMO does not click to me.

These guys are far more important for the knee than the bogus VMO.

4) Squatting wide with toes out puts the ADDuctors into a better line of pull to be hip extenders and cover up for inhibited glutes. This may be desirable in unique static situations like powerlifting or some versions of KB swings. But this does not support the original idea of more ADD = more VMO.  In fact, it may support bigger glutes, which is really where the money is at in training after an ACL.

To bottom line it, if the knee hurts, and the VMO is soft, leave it alone and use what you know to limit the pain. In the mean time, spare the knee with hip-dominant patterns and core work.  Obviously post-surgically, there is room for Russian NMES and standing TKE, but not much more than that as I see it.

I think Coach Boyle wrote an article that ACL prevention, which is ACL rehab after the ACL is fixed), is just Good Training. I guess the students at the conference must have missed it.

I’m currently working on my kettlebell moves, and I’d like to improve my hip mobility to achieve a perfect windmill and the double KB TGU.
I do my SMR regularly, can get a three (but barely) on the ASLR, and am starting to wonder if more “traditional” flexibilty methods would be what I need to get to that level of hip mobility, where I can bring my leg up 90 degrees while maintaining lordosis. By traditional methods, I mean static holds and some basic contract/relax, which is what another trainer here is recommending to me (she’s a former cheerleader/gymnast, to show you her bias).

First off, I will simply say that cheerleaders, dancers, and gymnasts have some of the worst quality of life in their adult ages as any of the general population folks I see.  That doesn’t mean every one is a goof, but heads of tails, traditional mobilization methods are not very contemporary as I see it.
That being said, go ahead and try it and see what you get. I’m not familiar with anyone who truly hurt himself with just stretching properly.

THESE.....are the cheerleaders you're looking for.

One reason I think passive stretching is ill is based on what I have talked before about the potentials of reflexive compensatory flexibility intra-muscularly if you are figuring out how to stretch around adhesions. The best way to figure out if you are in this boat is to have a good manual therapist scan the tissues. You can even try this yourself with a Stick.
If you have legit knots in the hamstrings, glutes, hip flexors, quads, really anywhere including the low back and calves, stretching may not get you to where you want to go.  The reason is because you may get longer in healthier regions of the tissue, but make no effect at adhesions or even worsen their tensions.  The “messages” the CNS receive from these adhesions/triggers/fibrotic tissues will likely negate the increased excursion and run the motor plan foul.  It’s not a guarantee that this will happen, but it’s probably also a measure of your tolerance of the movement.
Again, I don’t think the actual stretching will injure you. I think you might be creating an environment that leads to injury down the road. Again the only way to know is by engaging in soft tissue work before hand.
This article was from several months ago, maybe a year, where I put some thoughts together about stretching in general.

Also consider decreased ROM may be capsular. Mobilizing the stiff capsule is a very different and at times specific mobilization. Kaltenborn, Evenglyth, Maitland, and others are names to look for in terms of schools of clinical practice that can range the capsules. Stretching muscle with a stiff capsule may not yield you the answer you expect.

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A positional fault, while typically painful, may be yet another possible restriction that stretching won’t work with stretching. A different kind of manual therapy or taping may be the answer here, like a Mulligan approach, DNS active exercise, or kinesiology taping like Spidertech.

Bottom line is this though because you shouldn’t have to go through a 3-hour evaluation to get some inches on a range of motion.
1. Just don’t keep stretching if you not getting more flexibile. You are probably making it worse.
2. However you get more mobility, always lock it in with a little stability. Come back and get some more mobility, and lock it in with stability.
3. Big lifts should be full and deeply excursioned. Pull-ups to a dead hang and huge grip. Swings and DLs with a huge hamstring stretch on the back end. Lockouts on presses with a stiff packed shoulder. Long strides in sprints.

Get it the right way, of which there are many, lock it in, and then use it aggressively. This process will release the sympathetic tone that is probably what is holding you back.

In terms of the windmill specifically, I’ve found that the popping the hip out becomes so much easier with dry needling, again not stretching in the traditional definition, to the glute medius, glute minimus, and multifidus, has led to giant changes.  But those changes are not designed to last without patterning afterwards.
I just think if something’s stuck, demanding it to unstuck just doesn’t work, and it certainly doesn’t work quickly.  If needles change things so immediately, how can it be a muscle length issue that needs stretching?

It can’t.

Stretching is like kicking the locked door down. Dude, it only works in the movies.