A warm-up is designed to do a great many things: It prepares your body for action, it gently eases the muscles into a power-up mode. It makes sure your body temperature and blood flow begin to rise in an easy gradient. It hopefully helps prevent injuries that can occur when muscles are not quite ready to fire at their peak just yet. It also helps take your mind into the right headspace so that you can really focus on what you're doing. This should be your go-to warm-up drill before you launch into any exercise program.