Popular Science breaks down the science of it here, but after the first couple paragraphs it just started to look like blah blah blah blah blahblahblahblah…
1 thought on “Crazy exer-ball trick”
Yeah, looks like one of those things where moms say, “What are you trying to do, break your neck?”
Yeah, looks like one of those things where moms say, “What are you trying to do, break your neck?”