The Why and How of Hill Repeats: The Simple Workout That Hurts (and Works)
Hill repeats are exactly what they sound like: you run up a hill hard, recover, then do it again. They also feel exactly how you might imagine them to feel. When they first appeared in my training calendar, my immediate reaction was to call my coach and cancel everything I signed up for that might require this exercise. However, even as someone who used to absolutely despise uphills, I quickly learned to love my hill rep days.
Written & edited by Pavlína Marek
Let’s start with what hill repeats are not. They aren’t a race up a mountain, they don’t mean “accidentally” hammering every hill you see on a normal run, and they’re (mostly) not sprinting uphill until you see stars.
The reason coaches love them while runners tend to have a love-hate relationship with them is simple: hill repeats are simple, brutal, and they work. You don’t need access to a track, fancy gear, or perfect pacing to do your hill reps; you just need one hill and a little willingness to suffer in a productive way.
The Why: What Hill Repeats Do for Your Running
Flat intervals are great. Track sessions have their place. But there are simply some things that flat speedwork can’t provide. Speed, endurance, better VO2 max,… hills give you a few upgrades that are hard to replicate on flat ground (Taddese et. al).
Strength without the gym
Hills could be loosely described as strength training that looks like running. Every step uphill forces you to produce more force into the ground, which hits the big running muscles: glutes (power and stability), hamstrings (push-off strength), calves and soleus (ankle stiffness and spring), and hip flexors (knee drive, especially when you’re tired).
Hill repeats will also help you with speed (since they’re basically speed workouts on an incline) and can significantly improve your endurance levels. However, if you decide to include then in your training plan (which you definitely should), don’t just slap them on top of what you’re already doing; replace or shorten a different session first to avoid overtraining which can come along with such intense workouts. Also, make sure you get enough recovery time.
Better running economy
Hills won’t let you cheat. On flat ground, it’s easy to overstride, slump, and kind of “reach” for speed. A hill won’t let you do that. If you overstride uphill, you will stall. When you lean from the waist, you’ll fold. If your cadence gets lazy, you’ll feel it instantly.
When done well, hill repeats naturally reinforce shorter stride, higher cadence, better posture, and stronger push behind you, all of which are needed for good running economy.
Speed and stamina crossover
When you do your hill reps, you’re not just getting better at hills. You’re building power and aerobic strength that shows up everywhere.
Lower impact than all-out flat reps
This surprises people. Uphill running usually means less impact per step than sprinting hard on the flat because you’re forced to land on your forefoot and you don’t slam the brakes with each landing.
Important note: the workout is still stressful. It’s just a different kind of stress, and often easier on joints than maxing out on the track.
Mental toughness and pacing skill
Hills teach you how to stay controlled when it gets hard (and it will get hard). You learn what “hard but sustainable” feels like, which is basically the secret skill behind smart racing.
If you can keep your head cool, your posture goo, and your legs moving on rep 6 when everything is screaming at you to stop, a lot of race moments will start feeling manageable.
Pick the Right Hill: Grade, Surface, and Length
I have to come clean with something. When you’re reading advice from articles I wrote, it’s a “do as I say, not as I do” kind of situation.
I learned that picking the right hill matters the hard way. On my first hill rep workout, I just picked the meanest hill I could find near my home, thinking that if the point of hill repeats is to suffer, I’d go big or go home. I can now confidently say that an 18% grade on a barely visible trail through the woods where you consistently slip on old beech leaves and have to look out for rocks is not a good choice for your first time. (I know, what a surprise.) Long story short, you can make hill repeats either amazing or awful just by choosing the wrong hill.
Surface: road vs trail
Both work, but they feel different and will yield slightly different results.
- Trail: softer landing, often easier on the body, but can be uneven and harder to run smoothly.
- Road/pavement: predictable and consistent for the uphill, but the downhill can be harsher on your legs.
If the downhill is sketchy (loose gravel, sharp turns, bad footing), pick another hill. It might be surprising but the downhill recovery is where you can also get hurt.
Grade: aim for 4–8% for most runners
A good general range is 4–8% incline. Too shallow and you’re basically doing flat intervals. Too steep and it turns into a power hike, your form breaks, and your calves (and back if your posture is weak) hate you for days.
What grade you choose will also depend on the length of your intervals (short sprints can generally be done on steeper terrain while longer efforts will usually call for lower grades) and your previous experience with hills (if you’re new to hills, and/or have never lived and run in a hilly area, start closer to the lower end).
Length: match the rep to the goal
As with other aspects, your rep length will depend on what your goal for the session is, what race you’re training for, your previous experience, and how your body works and responds to training.
- Short (10–30 seconds): power and speed
- Medium (45–90 seconds): strength-endurance (“runner strong” zone)
- Long (2–5 minutes): aerobic strength and stamina
Don’t do all of these every week. (Remember what we said about overtraining?) Pick one based on what you’re training for. Something else will work for you than what works for your friend. For example, my longest hill reps when training for my hundred was “only” 60 seconds, and I focused on short and medium hills on bi-weekly basis. My friend’s hill reps for the same race were in the medium to long range.
Quick safety checklist
- Can cars see you (and can you see them)?
- Is there a shoulder or safe path?
- Is the surface stable?
- Is the descent controllable?
- Is it well-lit if you run early/late?
Treadmill incline can work
No, treadmill isn’t cheating. Bad weather, bad traffic, no hills nearby? Treadmill is fine. (Though why you’d want to do that to yourself is beyond me. Me and the “Dreadmill” are not good friends, and I bow before you if you can do a treadmill workout without losing your mind a little!)
To replicate outside conditions, set your treadmill to 4–8% incline for most repeats. Don’t crank the speed so high your form falls apart, and recover by lowering speed and incline, not by stepping off every time (unless you need to).
How to do hill repeats correctly
1) Warm up like you mean it (10–30 minutes)
Don’t raw-dog hill repeats from a cold start. While research shows that warming up might not be as important for slow, endurance-based efforts, it does speak in favor of warming up for sprints and power sports (McGowan et. al), which is exactly what you’ll be doing during your hill rep workout.
- Do 15–30 minutes of easy jogging (I use this time to approach my hill since it’s further from the trailhead)
- Do a few dynamic drills: leg swings, high knees, skips, butt kicks,…
- You can add on 2–3 short strides on flat ground (10–15 seconds, smooth, not sprinting)
You want to start the first rep feeling ready and warmed up, not stiff or already exhausted.
2) Use effort, not pace
Pace is unreliable uphill. Wind, grade, and surface all mess with it. Go by RPE (Rate of Perceived Effort):
Most hill repeat sessions should feel like 7/10 (My coach had me on 7 for the longer efforts and 9 for the shorter ones. My friend, training for the same race, was between 5 and 7. Again, yours will vary depending on your strengths, weaknesses, experience, and race goals.) You should get to the point where it feels hard, you’re focused, and your breathing is heavy. Your effort should be controlled enough that you could do a few more if you absolutely had to.
If you sprint the first rep at RPE 10 and can’t replicate it in 20 seconds when it’s time for another one, the quality of your session will drop fast and you’ll not only miss out on some of the benefits of the workout but also increase your chance of injury.
3) Simple form cues
When things get ugly and the burn hits, keep your mental list of what to do very basic.
- Tall chest (don’t fold)
- Quick feet (cadence up, stride shorter)
- Push the ground behind you (don’t “reach” forward)
- Relax your face and jaw (sounds goofy, helps a lot)
Also, a slight lean is fine, but lean from the ankles, not your waist.
4) Recover on purpose
Most hill repeat recoveries are either an easy jog/walk back down, time-based easy recovery (especially on treadmills), or combination of the two. The goal is to start each rep ready to run well again, not fully fresh, but not destroyed either. You are allowed to walk during your recovery.
5) Cool down
After your session id over, jog easy for 5–15 minutes. If jogging feel like too much, do two things: one, switch to walking for the cool-down and two, work to manage your RPE better next time. Your calves and Achilles will thank you later.
Your Dont’s: Common Mistakes That Waste the Workout or Cause Injury
When it comes to hill reps, there are a couple “don’ts” that you’ll want to avoid in order to keep yourself happy and healthy. If you’ve read through the section above, you can probably come up with a couple of these yourself. Nonetheless, here are the biggest mistakes people make when doing hill repeats.
1. Don’t go too hard too soon
Your first rep should feel controlled. If you’re gasping like it’s the final sprint of a race, you’re overcooking it and will pay for it later.
2. Don’t pick a hill that’s too steep
If you’re forced into a power hike instead of a run, you’re training something else. It’s not bad, and power hiking certainly has its uses in racing; it’s just not the same workout. For classic hill repeats, keep it runnable.
3. Don’t race the downhill
This is a big one. Flying downhill is how you’ll end up with angry knees, tight calves, or a surprise tweak. Your descend (which is also your recovery) should be relaxed and controlled, especially early in a training block.
4. Don’t do hill repeats every week all year
They’re powerful, which is exactly why you should cycle them. A common approach would be 4–8 week block of hill work once a week, then shift toward flatter speed or race-specific sessions. Later on, maintain with occasional hill work.
5. Don’t ignore soreness signals
Some calf and Achilles tightness is common after hills. Sharp pain is not. If your lower legs feel like they’re turning into piano wires, back off and adjust.
3 Hill Repeat Workouts You Can Start Doing Today
Don’t forget to add in a warm-up and cool-down as discussed above (How to do hill repeats correctly—Warm up like you mean it) to help prevent injury and stiffness!
These hill repeat workouts usually replace one speed session. As I said earlier, don’t just tack them onto already-existing plans; take something out to make space for them. And keep the next day easy.
How Often to Do Hill Repeats and Not Get Injured
For most runners 1 hill session per week during a 4–8 week block will be a good goal to aim toward. If you already do heavy speedwork (track + tempo), hills every other week can be plenty. I’m going to repeat myself once more and tell you to replace one of those speed sessions instead of adding the hill reps on top of it. Also, avoid stacking hard days back-to-back. Don’t do hill repeats the day after a brutal interval workout.
Progression
If you find your hill reps are getting easier and not giving you much in return anymore, a good progression order is to add reps, then add rep length, and only then increase intensity slightly.
Keep weekly increases small, about 10–15% more total work. Not every session should be a complete makeover. Also, plan for some de-load/cut-back/recovery weeks.
Strength and mobility support
Do you want to prevent injuries? If yes, your best bet is to do supportive strength and mobility workouts. As a bonus, it might help you avoid some of that usual post-hill soreness. During your strength and mobility training, try calf raises (straight knee + bent knee for soleus), glute bridges or hip thrusts, single-leg RDLs, and ankle mobility drills.
The Fastest Way to Get Better at Hills Is to Run Them
- Pick a sensible hill (runnable grade, safe descent)
- Warm up properly
- Run reps by effort, not pace
- Keep your form tall and quick
- Recover with control
- Progress gradually in a 4–8 week block
If you want the easiest next step: do the beginner workout this week, then repeat it for 3–4 sessions before changing anything. You’ll get stronger faster than you think.
Hills never feel easy, but they do make you confident. And that confidence shows up everywhere, from flat tempos to race-day finishes.
FAQs
What are hill repeats?
Hill repeats are har uphill efforts, with recoveries by jogging or walking back down (or a flat recovery on a treadmill) and repeating this cycle. They’re basically speedwork on steroids. Their purpose is to build strength and improve running performance.
Why do runners do hill repeats instead of just flat speedwork?
Hill repeats bring unique benefits that flat intervals don’t or even can’t, such as targeted strength training for key running muscles, improved running economy by enforcing proper form, improved speed and stamina, lower impact on joints compared to all-out flat sprints, and development of mental toughness and pacing skills.
How do hill repeats improve running strength without gym workouts?
Running uphill forces your glutes, hamstrings, calves, soleus, and hip flexors to work harder with every step. This natural strength training directly transfers to better running power and stability without requiring separate gym sessions.
What kind of hills should I choose for hill reps?
Aim for hills with a 4–8% incline grade. The surface can be road or trail—trail offers softer landings but can be uneven; roads are consistent but watch out for safe descents. Match the length of the hill to your training goal: short hills (10–30 seconds) for power and speed, medium (45–90 seconds) for strength-endurance, and long (2–4 minutes) for aerobic strength and stamina.
Aren’t hill repeats harder on my joints than flat sprints?
Surprisingly, uphill running generally produces less impact per step than all-out flat sprints because there’s less horizontal braking force involved. While hill repeats are still a demanding workout, they often place less stress on your joints than max effort track sessions.
Can I do hill repeats on a treadmill?
Yes! Using a treadmill incline is an effective alternative when outdoor hills aren’t available due to bad weather or traffic.