Why ‘Time on Feet’ Is Such a Powerful Measure of Endurance
This story is from Manual, GQ’s flagship newsletter offering useful advice on style, health, and more, four days a week. Sign up here to get it in your inbox. Most runners take pride in detailed metrics—miles logged, pace per mile, personal bests. But there’s one simpler number that might deserve more of your attention: “Time on feet” (TOF), which is all about tracking how long you’re out there rather than fixating on distance or pace. Instead of aiming for a four-mile run at 8:30 pace, you could substitute a 45-minute session on a manual treadmill without worrying about how far or fast you went. While this approach is most popular in ultrarunning, where athletes spend hours and hours on the trail, it’s also beneficial for everyone from first-time 5k participants to seasoned marathoners—and, really, anyone who wants a higher VO2 max. (Which is everyone, right?) Keep It Simple For competitive runners, the pure amount of time you spend running is a strong indicator of success. A 2023 study showed that training volume—not the average or …