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Half marathon
Rating
A half marathon is a distance of 21.0975 km, exactly half of a marathon. It's one of the most popular distances among amateurs: long enough to be a serious challenge, but without requiring marathon-level training volume.
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Race time predictor
In detail
Unlike the marathon, glycogen depletion usually doesn't have time to become a decisive factor for most runners in a half marathon — the result depends more on tempo/threshold fitness (lactate threshold) than on pure endurance. This makes it a convenient distance for assessing current fitness ahead of a marathon.
How to use it
A half marathon is a good "check-in race" 4-6 weeks before your target marathon — the result lets you recalculate a realistic target marathon pace using a prediction calculator.