以下详细说明暂以英文提供。
How the Riegel formula works
Peter Riegel, an American research engineer and marathoner, observed in 1981 that elite and recreational runners alike slow down with distance along a near-power law: T₂ = T₁ × (D₂ ÷ D₁)^1.06. The exponent 1.06 means doubling the distance costs about 9% more time per kilometer. It is a statistical fit over many runners, not physiology, but it tracks real race results remarkably well from the mile up to the marathon when training matches the goal event.
Reading the prediction honestly
The formula assumes you have trained for the target distance. It is optimistic for a 5K specialist attempting their first marathon without long runs, and slightly conservative for a high-mileage marathoner racing a 10K. Heat, hills, altitude, and crowding at the start line all push actual results slower than the model. Use the number as a pacing anchor — run the first third of a goal race at or a touch slower than the predicted pace, then judge how much is left.
中国本地参考
日常计算时值得知道的中国本地规则：
- 计量的单位习惯: 住房面积用平方米，土地常用亩（1 亩 ≈ 666.7 平方米）；里程用公里，油耗用 L/100km。
- 日期与数字格式: 日期写作 2026年10月13日（年-月-日）；大数习惯用万、亿（1 万 = 10,000，1 亿 = 100,000,000）。
- 法定节假日: 全年法定节假日 11 天，春节与国庆为长假；调休安排每年由国务院办公厅发布。
- 速度与限速: 高速公路最高限速 120 km/h，城市快速路多为 80 km/h，均以公里每小时计。
- 鞋服尺码: 鞋码用中国码（毫米制），服装常用 155/80A 这类身高围度组合，与欧美码不同。
数据核对：2026 年 10 月
常见问题
Which recent race gives the best prediction?
A hard, recent, all-out effort at a distance close to your target. A parkrun 5K from last weekend predicts far better than a hilly half marathon from two years ago, because fitness drifts and tough courses inflate times.
Why 1.06 and not another exponent?
Riegel fitted 1.06 to world-record and club-runner data; it remains the standard because it matches observed fatigue between roughly 3 km and the marathon. Jack Daniels’ VDOT tables use essentially the same curve, while some predictors raise it toward 1.08 for first-time marathoners.