Guides
Plain-English explanations of the topics behind our tools, with worked examples.
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How to Estimate Your One-Rep Max Safely
Why estimated 1RMs are useful, how the Epley and Brzycki formulas work, and how to use percentages of your max in a training plan.
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Running Pace, Race Predictions and Heart Rate Zones
How to calculate running pace, predict race times with the Riegel formula, estimate VO2 max, and train by heart rate zone.