Quite often when the quads go numb, it is due to the hip
closing down and shutting off either blood or nerve flow to the area. The
antidote is to raise the spine, opening the hip slightly, while keeping the
knees still in space. If the knees go backwards in space, you know you are
simply hinging the hip, which will do little to help. You’re looking for the
space in the hip to internally open. After doing this, keep the spine where it
is and re-drop the tailbone to help the energy to descend into the earth. If
for any reason this doesn’t work for you, then, after a few minutes of standing
and the feeling of numbness, do some side to side weight shifts while maintaining
all of your alignments (without extending the width of your stance) to allow
blood and qi flow to return to the area. Then, revert back to your standing
practice. Hope this helps!