Hill Repeats

What they are and what they do

A hill repeat session is a set of hard uphill efforts, each followed by an easy jog or walk back down. Short reps of 30 to 60 seconds build power and leg strength. Longer reps of a few minutes work your aerobic system the way a tempo or threshold session does, and a long hill or an uphill treadmill (see the guide on the uphill treadmill) makes them easy to repeat.

Run them by effort, not pace. The same effort gives a slower pace uphill, so a pace target on a hill sends you too hard.

Running uphill softens the landing. In a 2020 treadmill study, at the steepest uphill slope (10 degrees, about 18%) and the fastest speed, the average loading rate of the force into the treadmill was 28% lower than on the level at the same speed¹. The way down is where impact rises: in a 2005 lab study at minus 9 degrees, impact force peaks were 54% larger and braking force peaks 73% larger than on the level, which is why you jog or walk down and do not race down².

Hills are not a substitute for lifting. In a 2022 study of 24 collegiate-level athletes sprinting on hills of up to 17.6%, every slope was low resistance, and the authors concluded that hills up to that grade do not provide enough resistance to optimize power development³. The guide on strength training for runners covers the lifting.

The training trials are small and short, and none tested a marathon. In a 2013 trial, twenty well-trained runners who did one of five uphill interval programs for 6 weeks improved a 5 km time trial by 2.0% on average, and the highest-intensity program was clearly best for running economy (2.4%) and for jumps on a force plate⁴. In 40 moderately trained middle-distance athletes aged 16 to 20, 8 weeks on the steepest gradient (about 7.6%) beat the control group on a 30 meter sprint speed, an 800 meter time trial and a one-minute burpee test⁵. So run the reps hard but controlled, and keep the grade moderate.

How to run them

Warm up with easy running and a few strides before the first hard rep.

• Pick a moderate grade, roughly 4 to 8%: steep enough to feel resistance and gentle enough to keep good form.
• Start with efforts of 30 to 60 seconds and 4 to 8 reps. Build toward 1 to 2 minutes as you adapt. Past three minutes, run the reps relaxed.
• Run hard and controlled, about 7 to 8 out of 10. Stay tall, drive your arms and push off the ground without overstriding.
• Jog or walk back down until you are fresh, then cool down easy.

Where they fit

Hill repeats suit a base or an early build, and they are a first taste of faster running for newer runners, who start with 15 to 30 second hill strides before full repeats. A hill repeat session is a hard session: count it in your two a week, and never put it next to another hard workout. The guide on interval workouts covers the flat version.