Get more from your walking workout by putting it in reverse.
Walking backward burns more calories, improves coordination, and gives your heart and lungs a better workout than hoofing it forward -- as long as you maintain your speed. The reason? It forces your leg muscles to work harder and in different ways. Just do it in a safe place (like the local high school or college track) where you won't bump into something and take a spill.
You can benefit from working out in reverse -- even if you're recovering from certain knee or leg injuries -- because it puts less stress on the knee joint compared with walking or running forward. It's not only a great way to build or maintain cardiorespiratory fitness, but it also requires your leg muscles to work in different ways -- and that takes energy (meaning it burns calories). Walking backward also forces a "concentric contraction" (shortening) of your quadriceps, a metabolically expensive movement (meaning it burns lots of calories) compared to the "eccentric" (lengthening) movement these thigh muscles make when you walk forward.
If you have problems with balance, walking in reverse is not recommended. If you think it sounds like something you'd like to try but you're concerned about falling, buy a lightweight bike helmet with a rearview mirror so you can see where you're going. Or try walking on a treadmill while holding onto the side rails; start slowly until you get the hang of it. Then, just put one foot behind the other. Step for step at the same speed, you'll get bigger benefits going backwards!
SOURCES: The metabolic transition speed between backward walking and running. Terblanche, E., Cloete, W. A., du Plessis, P. A., Sadie, J. N., Strauss, A., Unger, M., European Journal of Applied Physiology 2003 Nov;90(5-6):520-525. Epub 2003 Jul 26.