Key takeaways
Short steep hill sprints mainly build power and running economy, while 2 to 5 minute hills at near-VO2max effort mainly build aerobic capacity
In a 6-week study of well-trained runners, adding two uphill sessions a week improved 5 km time by about 2% whatever the hill length
On a treadmill set the gradient you want to train on, and use at least 1% incline for flat running
A hill repeats workout demands more force per stride at lower speeds, loading muscles and lungs while sparing some of the impact of fast flat running. Here is how to choose the hill, what the research shows, and how to use hills on a treadmill and in marathon training.
Short vs long hills
Hill length changes what the session trains.
| Hill type | Gradient | Rep length | Main effect |
|---|---|---|---|
| Hill sprints | Steep, 10 to 18% | 8 to 15 s | Power, stiffness, running economy |
| Short hills | 8 to 15% | 30 to 60 s | Speed endurance, economy |
| Medium hills | 6 to 10% | 2 to 3 min | VO2max |
| Long hills | 4 to 7% | 4 to 6 min | VO2max, threshold, strength endurance |
| Hill tempo | 3 to 5% | 10 to 25 min | Threshold, marathon strength |
What the research says about hills, VO2max and economy
The best study on this is Barnes, Hopkins, McGuigan and Kilding (2013) in the International Journal of Sports Physiology and Performance. Twenty well-trained runners, averaging around 95 km a week, were randomly assigned to one of five uphill programmes and added two hill sessions a week for six weeks:
| Group | Gradient | Reps (week 1 to week 6) | Intensity | Work:rest |
|---|---|---|---|---|
| 1 | 18% | 12 × 8 s to 24 × 12 s | 120% of speed at VO2max | 1:6 |
| 2 | 15% | 8 × 30 s to 16 × 45 s | 110% | 1:3 |
| 3 | 10% | 5 × 2 min to 9 × 2.5 min | 100% | 1:2 |
| 4 | 7% | 4 × 4 min to 7 × 5 min | 90% | 1:1.5 |
| 5 | 4% | 2 × 10 min to 2 × 25 min | 80% | 1:1 |
Key results:
- 5 km time-trial performance improved by about 2.0% on average, with no clear best programme. Any high-intensity uphill training helped.
- Running economy improved most with the steepest, shortest sprints (about 2.4% at the optimum), along with jump and stiffness measures.
- VO2max and other aerobic measures improved most near the middle, between the 2-minute and 4-minute hills; the modelled VO2max gain at that optimum was about 4%.
Caveats: groups had only three to five runners each, and the study ran six weeks. An earlier study by Ferley and colleagues, summarised in the Barnes paper, found that both uphill and flat intervals improved performance, with the only significant difference favouring the flat group. Hills are a good tool, not a magic one; see how to improve VO2max for the bigger picture.
A hill repeats workout you can use
| Session | Warm-up | Reps | Pace / HR / RPE | Recovery |
|---|---|---|---|---|
| Hill sprints | 15 min easy plus drills | 6 to 10 × 10 s on 10 to 15% | Near-maximal, fully relaxed form; RPE 9 | Walk down, 2 min total |
| Classic VO2max hills | 15 min easy | 6 to 8 × 2 min on 6 to 10% | About 5 km effort; 90 to 95% of max HR by the end of each rep; RPE 8 to 9 | Jog down, about 2 to 3 min |
| Long hills | 15 min easy | 4 to 5 × 4 min on 5 to 7% | 10 km to threshold effort; RPE 7 to 8 | Jog down, 3 to 4 min |
| Hill tempo | 15 min easy | 1 × 15 to 20 min on 3 to 5% | Threshold effort, about one-hour race effort; RPE 7 | none, easy cool-down |
Run by effort, not pace. Heart rate lags, so short reps will not show it. Use the heart rate zone calculator to set your 90 to 95% band and the VO2max running calculator to know what 5 km effort feels like on the flat. Keep the form tall, short quick strides, and drive the arms. Jog down gently: the descent is where impact is highest.
Hill repeats on a treadmill
Treadmills make hills precise and repeatable, which is useful if you live somewhere flat.
- Baseline incline: Jones and Doust (1996) found that a 1% treadmill grade most accurately reflects the energy cost of outdoor running in trained runners at the speeds they tested. Use 1% for warm-ups and flat segments.
- Rep incline: set the gradient you want to train, as in the tables above (6 to 10% for classic hill reps), and lower the speed until the effort matches the target RPE or heart rate.
- Recovery: drop to 0 to 1% and walk or jog. Unlike outdoors, there is no descent, so your legs take less pounding, but you also miss downhill practice.
- Limits: belts and motors take several seconds to change, so 8 to 15 second sprints are awkward and the straddle-and-jump-on method is risky. Favour reps of 1 minute or longer, and press the incline button before speed.
The Norwegian 4×4 works well this way: four 4-minute uphill reps at 90 to 95% of max heart rate, close to the "long" hills above.
Hill repeats for marathon training
For marathoners, hills earn their place in the base and early build phases:
- Base: weekly short hill sprints for economy and leg stiffness, plus hilly easy runs. These pair well with strength training for runners.
- Early build: long hills or a hill tempo once a week, building aerobic power and strength endurance.
- Specific phase: swap most hill sessions for tempo runs and marathon-pace work. Keep some hills if the race course is hilly, including controlled downhill running.
- Taper: a few short hill sprints keep the legs sharp without fatigue (tapering before a race).
Fit hills into your plan with the rest of the week mostly easy (80/20 training, periodisation). Hill surges on a rolling route also make a good fartlek, and runners on the Norwegian singles method can run a long-rep day on a gentle incline, keeping effort below threshold. More guides are on the running page.
Safety: hill work loads the calves and Achilles tendons; build up gradually if you are new to it. If you have a heart condition, high blood pressure, or have been inactive, get medical advice before hard intervals.
Frequently asked questions
What is a good hill repeats workout?
A solid all-round session is 6 to 8 × 2 minutes up a moderate hill of about 6 to 10% at a hard effort, around 5 km race effort, jogging back down to recover. Warm up for 15 minutes first and cool down for 10.
How do you do hill repeats on a treadmill?
Warm up at 1% incline, then raise the incline to 6 to 10% for each rep and lower the speed so the effort matches what you would run outdoors. Drop back to 0 to 1% and walk or jog between reps. Treadmills change speed and incline slowly, so longer reps work better than short sprints.
Are hill repeats good for marathon training?
Yes, mostly in the base and early build phases. Longer hills of 3 to 5 minutes and hilly long runs build strength and aerobic fitness with less pounding than fast flat running. In the final weeks, swap them for marathon-pace work, unless your race is hilly.
How often should I do hill repeats?
Once a week is enough for most runners, counted as one of your hard sessions. In research with well-trained runners, two uphill sessions a week for six weeks improved performance, on top of normal easy running.
Sources
- Barnes KR, Hopkins WG, McGuigan MR, Kilding AE. Effects of different uphill interval-training programs on running economy and performance. Int J Sports Physiol Perform, 2013.
- Jones AM, Doust JH. A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. J Sports Sci, 1996.