If you've never done a fartlek workout (or don't even know what that is), here's your chance to give it a try. Picking up the pace once a week goes a long way toward making you faster. But that doesn't mean you have to race around a track or keep your eye on a watch. Speed play, or "fartlek" in Swedish (the concept originated in Sweden), is a free-flowing format in which you run faster for however long (or short) you want to. Many great athletes, including the Finnish Olympic medalist Lasse Virén, have done their speed training this way. Choose from the two workouts below, or make up your own. Warm up by walking for three minutes, jogging for five, and finishing with six accelerations (of about 80 yards) to get your body ready for a faster pace.