“Muscles that are constantly contracted are working very hard even if we’re standing still. So as you can imagine, they require a great deal of energy in the form of ATP. But unfortunately, contracted muscles squeeze the blood vessels in the area, restricting blood flow and reducing the amount of oxygen and glucose that can be carried to the working muscle. This compression does not create long-term problems when muscles are given a chance to relax. But when muscles are held in a state of contraction for too long, constant compression of the blood vessels leads to ischemia, a condition in which lack of oxygen and nutrients can lead to pain, loss of function, cell damage, and even cell death.”