Dear Coach With Gordo Byrn

  • By Gordo Byrn
  • Published Mar 29, 2012
  • Updated Oct 31, 2014 at 4:37 PM UTC
Photo: John Segesta

What are the best interval sets to improve speed on the bike? These three sets specifically address the limiters that I see most often when working with athletes.

» To improve your performance on the flats, do Big Gear Intervals: Try 5×8 minutes in a big gear with 2-minute spinning recoveries.

Aim for 60 RPM in your TT position.

Use a threshold effort, where you build to a burning in the legs then back off a touch.

Keep your head up when riding fast!

» To improve your ability to boost effort then recover at race pace, do 12/3s: Alternate 12 minutes at race-specific intensity with 3 minutes one zone up (if you’re racing Ironman, do your 3 minutes at half-Ironman race pace).

Olympic-distance athletes can build to 45-minute sets (3×12/3 continuous), 70.3-distance athletes can build to two 75-minute sets (5×12/3) and iron-distance athletes can build to two 90-minute sets (6×12/3).

Most athletes overestimate optimal bike effort, so start a little easier than you think you need to.

For an added benefit, change your cadence in the middle of each 12-minute segment. For example, alternate 92/60/92 RPM for each 4-minute chunk.

» 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, the co-author of Going Long and a past champion of Ultraman Hawaii.

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