rollstep

a type of walking motion used in a number of contexts; it is where you walk slightly crouched, and you roll your feet.

the net effect of this is that your torso stays relatively still, even when in motion. This makes it easier to, say, play an instrument, as opposed to having your torso moving up and down like in a normal walking motion.

It is also used by Rainbow Girls and Eastern Star, as they tend to wear ankle length dresses and hoop skirts. In order to appear like their torsos aren't moving, they do what they call "glide walking" but is really rollstepping.

in marching band and drum corps, rollstepping (or crabwalking, if you're in the drumline; color guard is cool too.) is used to make it a little easier to play an instrument.