To get ready for any race distance, you need a mix of runs on your schedule. Easy runs build your aerobic base, comfortably hard threshold training builds speed endurance , and speed intervals , including VO₂ max workouts, elevate your peak aerobic capacity.

To execute these workouts effectively, it helps to have pace targets. “Pacing is just one of the many tools we can use to expose the body to those different intensities,” says Mike McMillen , Charlotte, North Carolina–based RRCA level II- and USATF-certified run coach and founder of Flow Motion Running .

But there’s a catch: Training with a single pace target can make any workout feel like a pass-fail exam rather than a useful training session.

“Having a range is extremely valuable,” says McMillen.…