The Collapser is exactly what it sounds like.  Someone who conforms to the ground way too much.  They absorb force in an alternative plane to the sagittal, leading to abnormal forces.  How important is this?

Let’s look at what a Collapser looks like first.  You’ll notice the 2 hallmark signs of a Collapser (Picture to the Right):  Pelvic drop and an adducted/internally rotated hip. 

Typically, a runner will have one or the other, but you’ll note that this runner has both.  This can correlate with anterior knee pain³, lateral hip pain¹, and a host of other issues.

So back to why it is so important.  When we walk, 3x our body weight goes through our knee.  When we run, this...