Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
There are times when you're walking that the pressure on your feet exceeds your body weight, and when you're running, it can be three or four times your weight.
62
Poor eyesight (myopia) is associated with higher IQ.
232
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
Your thumb is about the same size as your nose.
124
When you take a step, you are using up to 200 muscles.
886