Looking for a way to spice up your time on the treadmill? Try sprinting intervals.

You've probably seen this done on "The Biggest Loser," but you don't need Jillian or Bob breathing down your neck to do it yourself. Simply increase your speed by 25 percent above your average speed and run at this pace for 20 seconds. Piece of cake? Increase it to 30 seconds and do this two or three times per workout. Gradually increase your sprinting time until you're able to keep it up for two straight minutes. Just make sure you do it safely -- practice jumping onto the side panels a few times in case you need to stop suddenly while you're sprinting.

Why should you do this? Well, you'll up your calorie-burn, you'll give yourself an energy boost in the middle of your workout and you'll gradually increase your running speed, endurance and overall fitness. Is 20 seconds of pain worth all that? You betcha.