What happens to your nerves when you stretch, walk, bend or move from one position to another? Now consider your nerves are like wires running through your body. So if you bend your knee the wires bends and nothing happens to them. But when you reach out to something, grab it and lift it overhead, your nerves gets straightened and tightened and gets reproached. The nerve also gets glided to prevent over stretching. This gliding is needed to prevent the building up of tension in the nerve.