3. To improve your intensive aerobic ability, do Lactate Threshold (LT) Intervals.
LT intervals are intense, aerobic efforts where you can hear your breathing but do not feel burning in the legs. A monthly 40-minute LT test serves as a good benchmark to track fitness.
Aim for a cadence of 92 RPM, build your effort gradually and stay just below the point where you feel burning.
For the technically minded, 80–85 percent of functional threshold power (FTP) is optimal, and you should cap your heart rate at 8 BPM under FTP heart rate. With experienced athletes, the duration of LT benchmarking can increase up to 2.5 hours (use very sparingly).
Gordo Byrn is the founder of Endurancecorner.com, the co-author of Going Long and a past champion of Ultraman Hawaii.