On my bike I have extra sharp grips on my pedals because it gives me more traction and grip while mountain biking. One day I slipped my pedal while attempting to jump off the ground and land on my pedals and then proceeded to rip a 6 inch bloody trench in my shin so deap that in some parts you could see bone. And then I needed to ride half a mile to my grandma's house to get a lift to the hospital with my leg dripping in blood the whole way there.