3. The most demanding workout of the week should challenge you above and below the pace that you will actually run on race day.
For all distances, I find that the most effective workout is a high-quality two-hour long run (for less experienced runners, strive to get your long run up to the two-hour mark, even if that means running slowly or integrating walking breaks). To simulate race-day stress, place main sets at the end of the workout. The purpose of placing the main sets late in the session is to create a habit of negative splitting the back half of your runs. All other run volume in this session should be an easy or steady effort. These workouts will help train your body to recover while running slightly slower than race pace, and expand your ability to tolerate pace changes around average race pace.
Ironman: Insert 3×25 minutes running 10 seconds per mile faster than average race pace. Recover with 5 minutes running 20 seconds per mile slower than average race pace.
70.3: Insert 2×4 miles where you alternate a mile 10–15 seconds per mile faster than average race pace with a mile 10–15 seconds slower than race pace for recovery. Power walk for 10 seconds after each mile and 60 seconds between sets.
Olympic: Insert 2×3 miles where you alternate a half-mile at 10 seconds per mile faster than average race pace with a half mile 10 seconds per miles slower than average race pace. Do 2 miles at 1 minute per mile slower than average race pace between sets.
These sessions are demanding but achievable when done as prescribed. A successful session will prove your ability to handle that specific pace, which will give you the confidence to extend your limits on race day.
Gordo Byrn is the founder of Endurance Corner (Endurancecorner.com), a past champion of Ultraman Hawaii and co-author of Going Long.