Why do all of the lifeguards in the water park shake their head yes all the time and swoop their head? I've been to other water parks and the lifeguards don't do that.

This is how they are trained to look for issues that arise in the runtime for the park, be it, a child by themselves struggling with something or whatever. I'd ignore it, as it shouldn't impact your fun at the park.

I believe that's how they are trained to constantly look for issue's.

Unfortunately I never saw this done. But I believe it would be to properly scan the area.

That is the proper technique for lifeguards to scan a pool. I'd be worried if they weren't doing this. It's a mark of proper training.

Great Wolf Lodge lifeguards also do this

Like the previous comments Nd also I was told by an employee that is how they are trained. This helps them.to address an issue quickly.

New England way!