Physics weights revolve around a principle that prevents one of us ... Gravity. And 'the attraction of the earth, we use our muscles every day in all our movements. If we do not focus on the battle, we simply lie down and even our lungs stop working.

With the fight against gravity, we can strengthen our bodies, little or as much as we need or desire. The higher the density of an object, the moreAttraction. Therefore, it is harder and harder for us to lift and maneuver. This is the basis of lifting weights. You move an object against gravity.