The forecast for 10km would be 76 secs/400m.”īottom line: John’s 1500m time is comparable to 8:30 for 3K, 15:00 for 5K, and 31:40 for 10K. If we add a further 4 secs to the 3km prediction (72 secs), that is his forecast for 5km. “If we now add 4 secs to this (68 secs), that is his forecast for running 3K. Horwill’s brainstorm was to note that paces at the standard race distances: 1500m, 3000m, 5K, 10K, half-marathon, and marathon follow a fairly linear progression, with each step up the ladder entailing about the same amount of slow-down as the one before it.įor example, he wrote in an undated article now reprinted by the London-based Serpentine running club, consider “John,” a 4-minute 1500m runner. It’s also a pretty good rule of thumb for road runners trying to extrapolate a 5K goal from a mile, or a marathon goal from a half-marathon or even a 10K.

Some decades ago, British coach Frank Horwill, founder of the British Milers Club, developed what he called the 4-second rule for establishing training paces.įor Horwill, it was mostly an adjunct to his five-pace training system, used by such 1970s and ’80s luminaries as Sebastian Coe (two-time Olympic gold medal winner at 1500m), Tim Hutchings (4 th in the 5000m at the 1984 Olympics), and Said Aouita (world-record holder at four distances, and 1984 Olympic 5000m winner).īut the rule isn’t just a way to establish training paces under Horwill’s system (in which you train at race pace, plus two “paces,” faster and slower, to each side of it).

Download calculating half marathon pace