Training guide
Incline walking means walking uphill, on a treadmill slope or a real hill. The 12-3-30 workout, a 12% incline at 3 mph for 30 minutes, made it popular online with claims of easy fat loss. The one study of it found it burned about 300 calories in 30 minutes in 14 young, active adults: about as hard as a gentle jog, and vigorous for most people.
Going uphill works your hips and calves harder, and in small lab studies, a slow walk up a gentle slope loaded the knee less than brisk flat walking, though descents load it more. No trial has tested 12-3-30 for weight loss. This guide sets out what incline walking costs in energy, what it does to your knees, calves, Achilles and back, how it compares with running and how to build up safely, with uphill moves, strength work for your calves and three follow-along walks.
A treadmill's incline is a percentage grade, the rise for every 100 units travelled, so 12% is about 6.8 degrees (our arithmetic), not 12. The workout spread on YouTube and TikTok after the influencer who posted it said it helped her lose 30 pounds.
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In the one study of it, 14 young, regularly active adults who didn't hold the rails burned about 10 calories a minute, about 300 in 30 minutes: roughly 8 METs (metabolic equivalents, or multiples of the energy you use at rest; our arithmetic), close to the 8.8 the Compendium of Physical Activities gives for walking up an 11 to 20% slope. One of them couldn't finish it. Older, heavier or less fit people may differ.
In a lab study, walking at the same pace took about half as much energy again on a 5% slope and roughly double on a 10% slope. Your hips and calves do most of the extra work.
In small lab studies, walking slowly up a gentle slope loaded the knee less than walking briskly on the flat. But knees bend more uphill, so kneecap pain may not ease, and walking downhill roughly doubled the force through the knee.
A self-paced run matched 12-3-30's calories in 24 minutes instead of 30, and running lands with about twice the force of walking. With the same energy used, walkers and runners had similar falls in the risk of high blood pressure, high cholesterol and diabetes.
Start with gentle slopes and add a little at a time, especially if your calves or Achilles complain (our suggestion). Gripping the handrails cut oxygen use by 15 to 21% at the same setting in a small study, so let go: a light touch for balance is fine.
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Treadmills set the incline as a percentage grade: how many units you rise for every 100 you travel. So a 12% incline is about 6.8 degrees (our arithmetic), and some pages wrongly call 12-3-30 "a 12-degree incline". 3 mph is 4.8 km/h, about the pace the NHS calls a brisk walk on the flat.
The influencer who created it posted it on YouTube in 2019 and on TikTok in 2020, saying it had helped her lose 30 pounds and keep it off without dieting; she did it about 5 days a week. That's one person's account, not a study.
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There are lab studies of how a slope changes energy use, muscle activity and joint loads, one small study of 12-3-30 itself, and one study comparing a 20% incline walk with jogging. We found no trial that tested 12-3-30, or a programme of incline treadmill walking, for weight, fitness or health in healthy adults.
In 16 fit adults averaging 33, walking at their preferred pace (about 2.9 mph), the energy cost of walking rose 52% on a 5% slope and 113% on a 10% slope. In 24 adults averaging 75 who walked more slowly (about 1.4 mph), it rose 23% at 10% and 44% at 16%. Across 1,412 lab trials, speed, slope and the load you carry predicted walking's energy cost almost perfectly.
16 regularly active adults (average age 25, weight about 75 kg) did 12-3-30 without holding the rails and, on another day, ran at their own pace until they had used the same energy; 14 completed both. 12-3-30 burned about 308 calories at about 10.2 a minute, and the run matched it in about 24 minutes at 13.1 a minute. One woman couldn't complete 12-3-30.
It's one small study of young, active adults: older, heavier or less fit people may differ.
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The 2024 Compendium of Physical Activities gives the average energy cost of activities in METs; multiply by your weight in kg and the time in hours to get calories. Our arithmetic for 30 minutes at 70 kg:
The Compendium's authors say its values don't reflect any one person's exact energy use. Heavier people burn more and lighter people less, and fitness and walking style change it too. Our calories burned calculator does the sum for your weight.
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In 22 inactive young adults, 20 minutes of walking up a 20% slope at 1.8 mph used the same oxygen and calories as jogging on the flat at 3.9 mph (about 170 calories each), with the same heart rate and effort ratings. But the joggers enjoyed it more, felt better by the end, and more of them said they'd do it again.
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In 10 adults aged 38 to 60, gripping the handrails cut oxygen use by 15 to 21% and heart rate by 12 to 21 beats a minute at the same speed and slope. Holding on means a lighter workout than the display suggests.
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12-3-30 drew a higher share of its energy from fat than running did (about 41% against 33%), but it burned less energy per minute. The study's own authors note that total energy use, not the fuel mix, drives weight loss, and exercise alone takes weight off slowly: about 2.8 kg at 150 minutes a week across 116 trials.
In 10 young adults walking up a 9 degree slope (about 16%), muscle activity rose most in the hips: the study reports increases of 345 to 635% in the buttock and hamstring muscles, 165 to 366% in the thigh muscles and 136 to 175% in the calves, compared with flat walking. Walking down the same slope, only the thigh muscles worked harder. Uphill, most of the extra support comes from the hips; downhill, from the knees.
Your calf muscles pull on the Achilles tendon, and they worked much harder uphill, so the tendon takes more load (our reading). In a study of 6 men, the Achilles tendon stretched substantially with each step on the flat and on a 10% incline, and the calf muscle worked at longer lengths as the slope rose.
If you have Achilles or calf pain, build the slope slowly and use the rule our pain guides use: pain up to 5 out of 10 during exercise is acceptable if it has settled by the next morning. In a trial in Achilles tendinopathy, carrying on activity within a rule like this did no harm.
In 12 adults with obesity, walking slowly (about 1.7 mph) up a 6 degree slope (about 10.5%) gave a similar moderate effort to walking briskly on the flat (about 3.4 mph), with knee loads about 19 to 26% lower. In a second study of 19 adults with and without obesity, the same slow uphill walk cut the early force through the knee joint by 23 to 35%, and walking more slowly on the flat lowers knee loads too. At 3 mph, slopes of 10% or more lowered a measure linked with inner-knee load in 15 young men and 12 older men.
These are small lab studies in healthy or heavier adults, not trials in people with knee pain. And your knee bends more with each step as the slope steepens, while the thigh muscles work harder, so if you have pain around the kneecap you may not find uphill walking easier: keep slopes gentle, let your symptoms guide you, and see our runner's knee guide.
Downhill is the hard part for knees: on a 19% ramp, knee moments and power were much higher than on the flat, and the force through the knee joint reached about 8 times body weight against 3.9 on the flat. Take descents slowly with short steps, and use poles on real hills. On a treadmill you never walk downhill.
A 1996 study of 6 people suggested that a slope just over 12% might ease kneecap discomfort or strain on the anterior cruciate ligament in knee rehabilitation. That was the authors' suggestion, not a finding, and the same study found the knee bent more as the slope rose.
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In older adults, the muscle at the front of the shin worked harder as the slope rose, while in a study of younger adults it was the only leg muscle measured that didn't. If your shins ache, see our shin splints guide.
In 22 adults, walking on a 10% incline changed how much the upper body turned but not how the pelvis moved. People with lumbar spinal stenosis, a narrowing in the lower spine that causes leg symptoms on walking, walked longer on an inclined treadmill than on the flat, which is the basis of a diagnostic treadmill test. A walking programme that built up to hills and stairs helped stop low back pain coming back in the WalkBack trial, but no trial has tested incline walking for back pain.
Per minute, 12-3-30 is about as hard as a gentle jog and easier than a self-paced run. On the flat, running 1,600 metres cost about 1.3 to 1.4 times as much energy as walking it. On very steep slopes, the energy cost per metre of walking and running comes together, which is why walking is as efficient as running on steep climbs.
The force of each step rises from about 1.2 times body weight when walking to about 2.5 at fast running speeds, and even slow jogging landed with over 50% more force than walking. In a modelling study of 14 adults, the peak force through the knee was 2.7 body weights walking against 8 running, though because runners take fewer steps per kilometre, the load per metre travelled was similar.
In about 49,000 runners and walkers followed for 6 years, the same energy spent walking or running went with similar falls in the risk of high blood pressure, high cholesterol and diabetes. No trial has compared incline walking with running for fitness, weight or injuries.
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When steep walking and jogging cost the same energy, inactive young adults enjoyed the jog more and were more likely to say they'd do it again. Pick the one you'll keep doing.
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Our suggestions, from the studies above:
Editorial, built from the energy, joint and handrail studies above. Our incline treadmill workout turns it into four levels up to the 12-3-30 settings.
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The movement on the figure: Treadmill walking
Set a treadmill slope or find real hills at a talk-but-not-sing pace, use stairs or a stair machine for shorter, harder climbs, and save rucking (walking with a loaded pack) for hike training, starting at about 10% of your body weight as its guide suggests.
On 2 days a week, do 2 or 3 sets of 10 to 15 calf raises (the bent-knee raise works the soleus, the deep calf muscle), 2 sets of 10 to 15 tibialis raises and 3 sets of 8 step-ups on each leg, and stretch your calves for 30 seconds each side after walking, for comfort (our editorial starting point).
3D demoSlow calf raiseBeginner · A wall
3D demoSingle-leg calf raise from a stepIntermediate · A step + A wall
3D demoSeated bent-knee calf raise (soleus raise)Beginner · A bench or box
3D demoTibialis raiseBeginner · No equipment
3D demoStep-upBeginner · A step
3D demoWall calf stretch (gastrocnemius)Beginner · A wall
3D demoSoleus wall stretchBeginner · A wallThe incline treadmill workout builds to the 12-3-30 settings in four levels; the incline walking workout is a gentler hill walk; the interval walk adds fast minutes on the flat; hikers can add the hill and stair session, and the foot and ankle routine strengthens your calves and feet.
A steep treadmill walk that builds over weeks to the 12-3-30 settings (12% incline, 3 mph, 30 minutes), with a warm-up, a cool-down and stop rules.
40 minIntermediate3 movesCardio machine, A wallA 50-minute walk with hills, outdoors or on a treadmill slope: brisk on the flat, slower on the climbs, building from gentle slopes to about 6%.
50 minBeginner5 movesCardio machine, A stepA 40-minute walk alternating 3 minutes fast and 3 minutes easy, five times over: the interval walking tested in Japanese trials, built up from three rounds.
40 minBeginner3 movesCardio machine, A wallStair or hill climbs with the walk down as recovery, then a loaded walk with your rucksack, building towards the hills, pack and days of your trip.
40 minBeginner5 movesA step, Something with weightA steady 30 to 45 minute cardio session at talk-but-not-sing pace: walk, cycle, row or cross-train, counting toward weekly activity guidelines.
40 minBeginner3 movesCardio machine, A wallA 15-minute barefoot routine for stronger toes, arches, calves and ankles, finishing with balance. You need only a towel, a wall and a resistance band.
15 minBeginner11 movesA wall, Other / check instructionsThe walking plan adds hills from week 5 and offers the incline treadmill workout after week 8.
A free 8-week walking plan for beginners: build to 150 minutes of brisk walking a week, with intervals, hills and two short strength sessions.
6 training days40 minBeginner5 days a weekA 12-week workout plan for weight loss: three strength days, two cardio days and daily steps, building to 200 minutes a week, with honest results.
3 training days45 minBeginner7 days a weekA full week that mixes intensities: three strength days, two cardio days, a mobility day and an easy day, never seven hard days.
3 training days45 minBeginnerMost people can start walking without a check: WHO says medical clearance is generally unnecessary before activity no harder than brisk walking. Steep incline walking is vigorous, though, so check with your GP first if you have a heart, kidney or metabolic condition, or get chest pain, dizziness or breathlessness when active; the NHS also suggests a word with your GP if you haven't been active for a while. On a beta blocker, go by the talk test rather than your heart rate, as our zone 2 guide explains.
Stop and call 999 (don't drive yourself to A&E) for:
Treadmills show a percentage grade, so 12% is about 6.8 degrees (our arithmetic).
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It burned a higher share of fat (about 41% against 33%) but less energy per minute, and a run matched its calories in 24 minutes. Fat lost depends on your total energy balance, not the fuel mix during exercise.
At roughly 8 METs it's vigorous for most people, and one young, active adult in the study couldn't finish it. Build up to it.
Walking slowly uphill loaded the knee less than brisk flat walking in small lab studies, but your knee bends more uphill, your calves work much harder, and descents load the knee most.
Gripping them cut oxygen use by 15 to 21% at the same setting in a small study.
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Uphill walking raises buttock and hamstring muscle activity, but no trial has shown that it builds glute muscle. For that, our glute workout plan uses strength training.
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That's one person's account: she said she did it about 5 days a week, without dieting. No trial has tested 12-3-30 for weight loss, and European obesity guidance says to expect no more than 2 to 3 kg on average from exercise alone.
Walking on a treadmill at a 12% incline and 3 mph (4.8 km/h) for 30 minutes. It went viral after the influencer who posted it said it helped her lose 30 pounds. A 12% incline is about 6.8 degrees, and the workout is harder than it sounds.
It's a vigorous workout that burned about 300 calories in 30 minutes in young adults weighing about 75 kg, so it can help, but no trial has tested it for weight loss. Exercise alone takes off about 2 to 3 kg on average; eating less does more.
Not better, different. Per minute, 12-3-30 burned about as much as a gentle jog but less than a self-paced run, with much less impact through your body. Choose the one you'll keep doing: in one study, people enjoyed jogging more.
For a 70 kg person, about 245 calories in 30 minutes up a 6 to 10% slope and about 310 up an 11 to 20% slope, against about 170 for brisk walking on the flat (our arithmetic from Compendium values). Heavier people burn more and lighter people less; our calories burned calculator does the sum for your weight.
Going up slowly, often: in small lab studies, a slow walk up a 10% slope loaded the knee less than a brisk walk on the flat, and slopes of 10% or more lowered a measure of inner-knee load. But your knee bends more uphill, so kneecap pain may not ease, and walking downhill loads the knee much more. These were lab studies in healthy or heavier adults, not trials in people with knee pain.
It can, because your calves work much harder uphill and pull on the Achilles. Build the slope gradually, add calf raises, and if pain is still there the next morning, drop back a level. Our Achilles and shin splints guides have more.
No trial has tested it for back pain, but a walking programme that built up to hills and stairs helped stop back pain coming back in a large trial. Walk upright rather than hanging on the rails. People with spinal stenosis often walk further on an incline than on the flat.
It makes your glutes and hamstrings work much harder than flat walking, but no trial has shown that it builds glute muscle. For that, our glute workout plan uses strength training such as hip thrusts and squats.
Only lightly, for balance. Gripping them cut oxygen use by 15 to 21% at the same setting in a small study, so you'd be doing an easier workout than the display suggests. If you need to hold on, lower the slope or the speed.
Its creator did it about 5 days a week, but no study has tested how often is best. Our suggestion is 2 or 3 steep sessions a week with easier walks between, because steep slopes work your calves and Achilles hard.
Yes: start at 3 to 5% at a comfortable speed for 10 to 15 minutes and change one thing at a time, or follow the four levels of our incline treadmill workout. If you're short and 3 mph feels like a jog, slow the belt rather than holding on (our suggestions).
Both are climbing, and both are vigorous for most people: the Compendium puts walking up an 11 to 20% slope at 8.8 METs, and climbing stairs at 6.8 at a general pace and 9.3 at a fast one. Whichever you choose, don't lean on the rails. Pick the one you enjoy and can keep up.
Exercise education, not a personal prescription, and clinical review of these guides is pending. Check with a GP before starting hard training if you have a heart condition, chest pain, dizziness or breathlessness when active, and stop for sharp or increasing pain. Health disclaimer.
