VIDEO CASE:  Is this lateral  compartment weakness

Trying again here.  VIDEO CASE:  Is this lateral  compartment weakness ?
 
Quite simply, there are too many people playing doctor out there that do not have the ability to examine their clients appropriately. Here is another case of just that. 
It is clear that this client has left lateral compartment deficits. Or is it too much medial compartment tone ? Your screens and loading tests will not likely show you this specifically, this client may merely present, as they did in this case of left frontal plane hip-pelvis drift and a right cross over step.  If you have been with us for awhile, you know these 2 match up when it comes to locomotion. But one must solve the "Why" for the "how" to be accurate (how to fix it).  
But, if you are looking for weakness, you will find it here, yes, peronei and lateral gastroc are weak. But is it inhibition or neurologic or frank weakness ?  It is because of heightened medial compartment tone ? It could be, thus making one think of possible centrally mediated processes. 
And, is the ankle the source or the frontal plane drift (glute weakness) the source ? Cart or the horse ? Chicken or the egg ?  You have to examine your clients, on and off their feet, shoes off, socks off (yes, i took the socks off afterwards). Screens are not enough if you are trying to solve problems. Fixing how your client's improper loading is not a fix always, it could merely be teaching a compensation over a compensation to a problem.   Be smarter than the rest, get the knowledge to examine your clients deeper , and more specific, function. Then, how they are moving, and the movements that you see that you do not like, will make more sense.  
in this case, if you do not address the foot and the hip abductors and pelvis stabilizers, you lose, and so does your client as you build more strength into their asymmetry . . . .  eventually leading, possibly, to complaints.

More on landing mechanics.
Here is a recent article on landing mechanics. This article talks about the landing mechanics far past where I feel the first stage of vulnerability is, which is initial forefoot load, as i discuss in the video pertaining to landing from a jump or if sprinting (forefoot loading). IF landing occurs in low gear (lateral half of the forefoot), inversion risks are higher.
The medial foot tripod, high gear toe off (1st and 2nd mets) is where we should be taking off from, and landing initially upon. Anything lateral is vulnerable without the lateral column strength (lateral gastrocsoleus complex, peronei longus/brevis).
This article talks about knee flexion angles and ACL vulnerability, far after this initial loading response. The article some valid conclusions in that phase.

- Dr. Shawn Allen

Posture specific strength and landing mechanics.

http://lermagazine.com/article/posture-specific-strength-and-landing-mechanics

https://www.youtube.com/watch?v=8T9UzOaYxmo