Sprints and midgets, at least when I was driving, required arm restraints, a "Head net" on the right side of the cage to keep your head from getting outside the cage, and a screen to keep objects from hitting you in the face. I don't remember the drivers name but a guy got a dried mud ball in the face at Perris 10 or 12 years ago, crushed his face pretty bad.
I believe the Head net was conceived after Rich Vogler was killed when he slapped the wall with the right side of the car and his head stretched outside the cage. It wasn't a super violent hit, but he got far enough out that he hit his head on the wall or a pole or something.
The reality is the cages are so small it doesn't take much to get outside when you crash, the body can stretch incredibly when forced to do so.
One night at Ventura (sprint cars) my buddy crashed on the front straight and got his bell rung pretty good. Someone had video of it, and when we watched it, after a couple of flips and rolls the car came down hard and flat on the left side. You could clearly see him stretch and his head impacted the dirt.
Lost Coyotes MC