You're right. Human joints are not meant to handle all of that weight. You can do it up to about 350 lbs, and then it gives out. It's not meant to support more than that. If Hamber really wanted to get healthy, she'd swim or do water yoga/aerobics. The water could support her and she'd get a good workout.Just imagine all of the energy required to lift her 600 elbees upright and maintain a standing position. That’s what being destributed through her body on impact when she hits the concrete. Definitely enough to do some major damage. Even from only a few feet.
Of course, we know she doesn't want to be healthy and only "swims" to show the haydurs that she's liveeen.