Authority · the models explained
Training Philosophies & Zone Models
The people behind the models: Coggan, Friel, Seiler, Maffetone, Daniels and Lydiard. How their zone systems differ and when to use each.
The main training models
Every endurance plan is some mix of easy, threshold and hard work. These are the named ways athletes balance that mix. Pick one to go deeper.
Polarized Training & the 80/20 Rule
Seiler's 3-zone polarized model and the 80/20 intensity distribution: why most endurance athletes should train easy most of the time, hard rarely.
Pyramidal Training: The Intensity Distribution Explained
Pyramidal training is an intensity-distribution model: a large base of easy volume, moderate threshold work, and a small amount of high intensity. Here is how it works.
Threshold Training and the Norwegian (Double-Threshold) Method
What threshold training is, how the Norwegian double-threshold method works, and how amateurs can borrow the principle without a lactate meter.
High-Intensity Interval Training (HIIT) for Endurance
What HIIT is, how much endurance athletes really need, and how to apply it: VO2max intervals like 4x4 minutes and 30/15s, with honest fatigue caveats.
Aerobic Base Training: Building Your Endurance Engine
What aerobic base training is, why a big easy Zone 2 base (the Lydiard tradition) builds your engine, and how to apply it without going too hard.
Sweet Spot Training: Time-Efficient Power Gains
Sweet spot training means riding at roughly 88 to 94 percent of FTP for time-efficient FTP gains. Learn how it works, the trade-offs, and how to apply it.
Most training-zone systems trace back to a handful of coaches and scientists. They disagree on the details, number of zones, what anchors them, how hard to go, but agree on the fundamentals: build a large aerobic base, anchor intensity to a measurable threshold, and keep easy days easy. Here's who built each model on this site, and where to use it.
Andrew Coggan, Power zones & FTP
Exercise physiologist; co-author of Training and Racing with a Power Meter.
Anchor cycling training to Functional Threshold Power (FTP) and a seven-zone model expressed as percentages of it.
Coggan's framework made power-based training mainstream. FTP, roughly the power you can hold for an hour, anchors zones from active recovery (≤55% FTP) to neuromuscular power (>150%), with Sweet Spot (88–94%) as a high-efficiency band. It also introduced metrics like Normalized Power, Intensity Factor and Training Stress Score.
Joe Friel, LTHR zones
Endurance coach; author of the Training Bible series.
Set heart-rate zones from lactate-threshold heart rate (LTHR) measured by a 30-minute time-trial field test.
Friel popularized threshold-anchored heart-rate zones for amateurs, with a simple, repeatable field test: the average heart rate of the final 20 minutes of a hard 30-minute solo effort. His sport-specific zone tables for cycling and running are still a default for coaches worldwide.
Stephen Seiler, Polarized / 80/20
Sports scientist who quantified how elite endurance athletes train.
A three-zone intensity-distribution model: about 80% easy, 20% hard, with little time in the middle.
Seiler's research found that across rowing, running, cycling and skiing, elite athletes converge on a polarized distribution split at the two lactate turnpoints. The insight is less about exact zone borders than how much time is spent low versus high intensity.
Philip Maffetone, MAF / aerobic base
Endurance coach and clinician; creator of the 180 Formula.
Build a deep aerobic base by training almost entirely at or below a heart-rate ceiling of 180 minus your age (adjusted).
Maffetone's MAF method is deliberately conservative, prioritizing fat metabolism, health and injury prevention over short-term speed. Progress is tracked with the MAF Test: pace at a fixed aerobic heart rate should improve over weeks. It's influential in ultra-endurance and triathlon.
Jack Daniels, VDOT & pace zones
Legendary running coach and exercise physiologist; author of Daniels' Running Formula.
Derive every training pace from a single fitness number (VDOT) calculated from a recent race result.
Daniels combined VO₂max and running economy into VDOT, then defined five training paces, Easy, Marathon, Threshold, Interval and Repetition, as fractions of it. One race result yields a complete, individualized pace plan. His Daniels–Gilbert equations underpin most modern running-pace calculators.
Arthur Lydiard, Aerobic base & periodization
New Zealand running coach whose methods reshaped distance running.
Build a huge aerobic base first, then layer hill strength and speed in distinct training phases.
Lydiard's periodized approach, months of high-volume aerobic running before sharpening, produced Olympic champions and shaped generations of coaches. His emphasis on aerobic development at controlled effort is a direct ancestor of today's Zone 2 and polarized thinking.