eli5: Why do we feel a sort of whiplash when we miss a step, or try to step on a stair that isn’t there, like when you’re going up a set in the dark?

Question

eli5: Why do we feel a sort of whiplash when we miss a step, or try to step on a stair that isn’t there, like when you’re going up a set in the dark?

In: 3

Answer 1

Your brain expects your foot to land on a step, so it tells your body to keep moving forward. But your foot doesn’t land on a step, so your body stops moving forward. Your head and neck, however, keep moving forward because your brain hasn’t gotten the message that your body has stopped. This sudden, forceful movement of your head and neck is what causes whiplash.