I've only been there once since they built those steps. Do you have any idea how many steps there are? I have a challenge where I have to run 2,000 steps. There aren't many outdoor staircases in our area.
I believe there are about 85 on that metal stairway. There are also some cedar board steps further up river on the trail.
The Booth Rock trail in Algonquin would be a good place to do a lot of outdoor steps. Not sure about "running" them.