The covering on your brain is very delicate and even a car wreck of around 20-25MPH can cause a serious brain bleed if you are not wearing a seatbelt.
When I was little I flew off a tire swing that was spinning really fast and hit my head on a wooden post, actually blacking out before I hit it. I woke up and got up to play, though I was falling over and losing my balance constantly.
I had no ill effects from this I had no ill effects from this I had no ill effects from this I had no ill effects from this.
Just a slight tick.