A couple playing defensive lineman (played both ways, but my offensive stance was more upright) and one when I was hit by buick while riding my motorcycle.
The first one I woke up on the practice field, after being out for a couple of seconds, was dizzy and nauseous, got driven home by a friend and put to bed. Woke up a few hours later with him playing video games and we got some dinner. Scared him more than me and I was fine by that evening. The other ones had no real long lasting effects more than a sudden blackout and being mildly woozy and having headaches for a few hours afterward.
The first one I woke up on the practice field, after being out for a couple of seconds, was dizzy and nauseous, got driven home by a friend and put to bed. Woke up a few hours later with him playing video games and we got some dinner. Scared him more than me and I was fine by that evening. The other ones had no real long lasting effects more than a sudden blackout and being mildly woozy and having headaches for a few hours afterward.