I talked a bit about the rhythm of walking down stairs over a year ago. I was thinking about it again recently while watching Resident Evil.
There is one scene in the movie where the commando team realizes the elevator is out of service. So, they take the steps. The shot shows the team descending an open staircase in the middle of a larger sort of warehouse room. It was absolutely, far and away, my favorite scene from the movie.... and here is why:
There are two parts that leave me in awe. The first part of the scene shows one woman wielding a large gun and she smoothly goes from walking forward to walking backward. She moves at a completely even pace. Her shoulders stay level and solid the whole time. The second part is that as each gun-carrying soldier descends the steps they entirely avoid the "pa-dum, pa-dum" rhythm. It is so graceful.
I don't know if going down stairs at an even pace allows one to go faster. I also don't know if they really train people to do that in the army and such. I suspect that both are true (the latter because of the former). But, it's a pretty consistent thing in movies where soldiers go down steps.... and I find it awe-inspiring every time.