Part of me wants to print off that interview and leave it on the front desk at my gym so some of the trainers can realize what frauds they are.
You ain't kidding it looks dangerous. A while ago someone posted a picture of some guy squatting on a full Swiss ball with 135 pounds. Now, that was dangerous for him and the unlucky guy that was "spotting" him.
It's more like risk to risk ratios. There is not a benefit to be had from a strength perspective to doing squats on bosu balls.
It's not the potential for knee injury that scares me in that picture. It's the way his ankle is tweaked that just makes me cringe. You can't tell me he's not going to have some serious ankle issues later.
I partially tore my acl in december and it's STILL not 100%, everything makes me worried about a knee injury