Twice. Once after fucking up a backside roll in in to a vert bowl. I rolled through a puddle, my wheels slipped and I basically did a dead sailor straight to the flat bottom. That one also fucked up my sciatica for like two months. Having to sit on a cushion in high-school in the Midwest got me a lot of shit. The second time wasn't as serious. I was having some afternoon beers on a day off, and a friend hit me up to hit the local park. After getting warmed up, albeit still with a belly full of beer. I heeled out 5050ing a rail, landed on my gut, and let out a good bit of foam.