There are three kinds of runners, says Roy Benson, a trainer based in Atlanta, Georgia, and author of The Runner's Coach: competitive runners, recreational runners, and fit joggers. Competitive runners know who they are, so we'll leave them out of this. "Recreational runners can finish a race with a smile," says Benson. And fit joggers? "Those are people who want to lose weight and don't give a damn about anything else. They run around and around the block until they wear a path in the concrete." For those who find themselves in the second category or want to bust out of the third, it's time to strap on an HRM. This weekly program devotes four days to recovery training and two to aerobic and threshold training, via fartlek or "speed play" exercise. "It means running your heart rate up and down like a roller coaster," says Benson. "Swedish runners popularized it on trails through forests, where they would spurt ahead when the path was clear."

THE PLAN:
Monday, Wednesday, and Friday: Easy recovery days. Run your standard route for 20 to 45 minutes, at 60 to 70 percent (recovery training zone) of your MHR.

Tuesday and Thursday: Set your monitor to signal both 70 and 85 percent of your max heart rate. Warm up for ten minutes in the 60 to 70 percent, or recovery range. Then, over 30 to 90 seconds, increase your pace until your alarm signals you've reached the 85-percent mark—placing you into the threshold zone. "You don't want to sprint," says Benson. "Your heart rate doesn't actually rise that much during a sprint. Instead, gradually increase your heart rate to your target." Then ease off the intensity until your monitor signals you're back at 70 percent. When you feel sufficiently recovered, repeat. Shoot for five to ten reps per workout, spread out over 30 to 45 minutes.

Saturday or Sunday: endurance day. Run at 60 to 75 percent of your MHR for 60 to 75 minutes.

THE PLAN:
Monday, Wednesday, Friday: Over a period of eight weeks, do three ten-minute intervals at your target SSHR. Allow eight minutes of rest between intervals. Each week, take two minutes off your rest period. After you can ride 30 consecutive minutes at your SSHR, restart the process with 15-minute intervals and ten-minute rests. Shorten your rests weekly until you can ride 45 minutes at SSHR. Armstrong started this drill at six 15-minute intervals, eventually building up to riding for two hours at his SSHR target—with fairly impressive results.