The exercise place

Near the marina, there's a place that has several yellow devices that are used for exercise. The thing is, I have no idea what they are. There was this thing that looked like it was supposed to be for rubbing your back. After that, there was an interesting mechanism that had a seat that went up if you pulled down on two handles. There was also a thing that had a seat that dumped you out if pull back and a handle. If anyone has any idea concerning what this is, I am open to suggestions.

--By Rigel