Tone and strengthen your arms, shoulders, back, legs and other muscle groups with a set of stretchy resistance bands that are durable and easy to use. Check out sets of resistance cables with anchors designed to remain securely attached to your door or ceiling, as well as flex bands that loop below your feet or around your legs while you exercise. You can start out using bands with lower levels of resistance and work up to the higher levels as you get stronger. Many sets offer color-coded systems, so you know whether you're working with high or low resistance at a glance. You can even amp up the challenge by using a combination of bands simultaneously. Some sets of resistance cables come with guides and workout DVDs, so you get the basics down quickly.