Wow, I had no idea Lou needed a stunt double.
They'd rather not have their main star do the most dangerous stunts (in case something bad happens) since (if the show/movie is popular) you will lose alot of money.
If the stuntman is injured, they will get another stuntman, but if the star is injured, they have to have the production on half for a while, which is bad.
I didn't think The Hulk-series had such dangerous stunts though, but you learn something new every day.