so yes if you can flex it, that is great but does it flex when you need to use it in movement? one does not imply the other. it has proven that movement patterns do not translate to other movement patterns automatically. just because your glute is firing in one movement doesn’t mean it will fire correctly in another movement.

standing ideally demands the glutes. most of us stand around with our glutes turned off which is bad. but it is entirely possible (i’m a prime example) that one glute fires better than the other. like you, my right glute fires much more cleanly and easily in a variety of movements. but my left for some reason lags. 

i’ve been consciously squeezing glutes during a variety of movements to get them to fire properly (i’m not a CF guy but a KB guy).  i also worked with Roop and he had me work the TFL and adductors and it turns out they were inhibiting my left glute from firing.  now my left glute is doing much better AND it also keeps my navicular bone on my left foot from collapsing…