If you can't invert the gun and holster without it falling out, it is too loose in my opinion. If the holster has a retaining strap that is disconnected it can be loose until the strap is fastened.
I can squat, jump or run a couple of steps without any of my gun/holster combos letting go. They still release with ease when I draw.
I could run her without a problem if I had better breathing.