Every PaceWOD article explains why a number differs between your watch, a calculator, and lab testing — then tells you which one to train with. We cite methods (Riegel, Daniels, Friel, MET), show real scenarios, and link to the tool that produced the estimate.
Running Science
Physiology, pacing models, and what your race data actually means.
How to Improve VO2 Max
Interval formats, weekly structure, and why watch VO2 trends lag behind race fitness.
Read →VO2 Max Running Guide
What ml/kg/min measures, VO2 max pace, and when intervals actually move the number.
Read →Why Garmin VO2 Max Differs from Lab Tests
Firstbeat modeling vs gas exchange — and which number to use for training decisions.
Heart Rate Training
Zone definitions that match how you actually run — LTHR, max HR, and device presets.
Zone 2 vs Zone 3 Running
When easy runs drift into gray zone — and why most runners train too hard on recovery days.
Read →Zone 2 Running Guide
Talk test, decoupling, and building aerobic base without chasing pace on easy days.
Read →Best Heart Rate for Fat Burn
Why “fat burn zone” on your watch is misleading — and what zone 2 actually does.
Read →Zone 2 Based on LTHR vs Max HR
Side-by-side ranges for the same athlete — and why Garmin defaults often feel too low.
Wearable & Device Analytics
Garmin, COROS, Apple Watch — accuracy limits and how to interpret conflicting data.
Garmin vs COROS Heart Rate Accuracy
Chest strap ground truth, wrist optical failure modes, and when to trust each device.
Why Garmin VO2 Max Differs from Lab Tests
Algorithm inputs, update lag, and trend vs absolute value.
Performance Optimization
Race prediction, pacing, calories, and training plans with honest limits.
Sub 2 Half Marathon Plan
12-week structure for breaking 1:59:59 — threshold work, long runs, race-pace sessions.
View plan →Sub 4 Marathon Plan
16-week build to finish under four hours with marathon-pace specificity.
View plan →How Many Calories Does Running Burn?
MET-based estimates vs watch calories — and why distance matters more than pace.
Read →Running for Weight Loss
Deficit math, easy-run volume, and why speed work alone rarely moves the scale.
Read →Why Race Predictors Are Often Wrong
Riegel exponent, marathon specificity, and when to add 3–8% to the spreadsheet.
CrossFit Conditioning
Workout design for mixed-modal athletes — separate from running physiology content.
Best EMOM Workouts
Twelve EMOM templates by level — pacing, movement selection, and time domains.
See workouts →Training Plans
Structured blocks for common race goals — use with our Race Predictor and Pace Chart.
Beginner 5K Plan
8 weeks from walk-run to race day.
View plan →Beginner 10K Plan
10-week build with tempo and long runs.
View plan →8-Week 5K Plan
Full schedule with quality sessions.
View plan →10-Week 10K Plan
Progressive overload for PR attempts.
View plan →