I'm not sure what he's doing there. It looks like he's either exercising or performing some kind of test. He's wearing the jacket. His torso is actively moving and jerking the jacket. There is some kind of apparatus (tube) also attached to the jacket that is being propelled by his chest. His chest is bumping the apparatus is moving and jerking the jacket as well.

It's not clear how much of this motion is due to the effect of gravitation on the suit.