Weeks 1–3 (Foundation)
Credit: Michael Dodge / Getty Images

Swim
Join a master's swim class and make sure you get filmed. It's the only way to really see and correct flaws in your stroke and breathing. After three weeks you should be able to swim at least 1,000 yards without stopping. Tip: Practice with buddies. Open-water swimming is a contact sport.

Workout

Mon., Wed., Fri.
Warm up (10 percent of your total distance), then 600-750, 900-1,000, and 1,000-1,200 yds respectively at low intensity (65 percent of max heart rate – 220 minus your age), broken into intervals (20x50 yds with 20 secs rest or 10x100 yds with 30 secs rest).

Bike
Have your road bike properly fitted at a cycling shop to prevent lower back pain. By week three, be able to bike an hour at a brisk pace.

Workout

Week 1
Tues.: 45 mins at moderate intensity (65–85 percent max heart rate). Sat.: 60 mins at low intensity.

Week 2
Tues.: 55 mins at moderate intensity. Sat.: 70 mins at low intensity.

Week 3
Tues.: 60 mins at moderate intensity. Sat.: 80 mins at low intensity.

Run
Try running on your forefoot, striking with your toe first (not your heel), to help reduce the shock to your knees, ankles, and back. After three weeks, be able to run three miles easily.

Workout

Week 1
Wed.: 20 mins at low intensity. Sun.: 25 mins at low intensity.

Week 2
Wed.: 25 mins at low intensity (right after swim). Sun.: 35 mins at low intensity; 30 mins at moderate intensity.

Week 3
Wed.: 30 mins at low intensity (right after swim). Sun.: Six striders (100 yd run on a soft, slightly downhill surface, gradually accelerating to a controlled sprint) with 20 sec rests between sets.