With Motorolas, I found out the hard way that the mike needs to be secure.
The standard of putting the radio on the hip and the mike on the closest epaulette works, until you start running. Like in a foot pursuit. Then the mike (at least for me) comes flying off in a ballistic arc. It should hit the ground, but mine always managed to whack me in the nuts pretty hard first. Then you have to deal with the pain, and the fact that you are running full tilt after some bad guy with your mic draggin on the ground and threatening to trip you.
I have since worked my mic around the back, through the opposite side epaulette, and clipped it to the front of my shirt. You can talk into and keep your eyes to front (instead of turning your head), and if it comes loose, the epaulette keeps the mic from flopping around and getting lost (or impacting your groin).