The treadmill gets a bad rap. While running on the spot might not be quite as exciting as taking to the great outdoors, the treadmill can be a far more convenient option at times, and it saves you from freezing cold or wet conditions.
It’s also worth remembering that most of our outdoor runs aren’t actually in stunningly-scenic surroundings; they’re usually restricted to busy pavements or city parks, so let’s not get too sniffy about the treadmill.
Treadmill running is, however, different to outdoor running in some important ways, both in terms of how hard each style of running is and how it affects your gait. If you’re jumping on the treadmill for the odd training session but mostly running on roads or trails the differences are probably small enough that you don’t need to worry about them.
But it you’re running indoors most of the time it’s definitely wise to get the skinny on the differences and how you can set up a treadmill to better mimic the world outdoors.
Below you’ll find all the info on how running on the treadmill differs from outdoor training, plus tips on how to liven up any indoor sessions you do have on your schedule. Let’s kick things off with the key question – are you slacking off by taking your training to the treadmill?
Is running on the treadmill easier than running outdoors?
“Running on the treadmill is considered to be easier than on the road as the belt assists leg turnover coupled with a lack of air resistance, resulting in a reduced energy cost,” says Michael Harrop, physiotherapist at Pure Sports Medicine.
So yep, treadmill running is slightly easier. But only physically! Some people find the grind of staying in one place makes it tougher to maintain a fast pace indoors. If you can handle the mental challenge of treadmill running though, it’s a great place to knock out your speedier runs when you have a target pace in mind.
“Treadmill running is useful for speed work or tempo runs as it is easier to monitor pace,” says Harrop. “This is helpful especially if there is a specific goal you are working towards.”
If you’re lining up a PB attempt at a flat road race, where the route will be closed to traffic, it can be quite hard to replicate those conditions outdoors. You can end up trying to run at your target race pace on busy pavements instead, which is far from ideal. The treadmill can be a useful way to practise your race pace without the risk of speeding headlong into a pedestrian looking at their phone.
Does your running gait change when on a treadmill compared to running outside?
“Your gait changes on a treadmill as there is a discrepancy between the quadricep and hamstring work ratio,” says Harrop. “As the belt propels you forward it decreases the work of your hamstrings resulting in a feeling that your quadriceps are working harder.”
This is one reason why you might not want to do all your training on a treadmill ahead of an outdoor event, because your running action is different indoors. It’s also something to think about if you do gait analysis on a treadmill ahead of buying a pair of running shoes – you might actually run in a slightly different way in those shoes outdoors.
Focusing on your form when using a treadmill is important to reduce the differences. Keep your head up, rather than staring at your feet or the treadmill console. If you’re on a treadmill that has a running deck that’s too small for you, you can exacerbate the differences in your gait compared to running outdoors by cramping up your stride.
Cheaper treadmills generally have a smaller running deck, so look out for that if buying your own machine, especially if you’re particularly tall.
Can you set up treadmill to be more like running outside?
There is a way to make indoor running more like outdoor running, but you’re not going to like it.
“There is evidence if you increase the treadmill gradient by 1% it more accurately reflects the energy cost of outdoor running, which results from increased air resistance,” says Harrop. "Although the faster you run the more you will need to increase the gradient for it to be equivalent.”
We told you that you weren’t going to like it. If you want your treadmill runs to be more like running outdoors you’ve got to run uphill. On the plus side it’s only a small hill – 1% is an incline you might not even notice if you didn’t have to set it yourself on the console.
You might also find it makes your treadmill run more smoothly at high speeds – if you crank up the pace too much on a 0% incline many treadmills start to shake and clank quite dramatically.
Is there any difference in the risk of injury between running on the treadmill compared to outside?
There’s some good news for treadmill fans here, in that it’s much harder, if not impossible, to trip over a tree root or get hit by a bus while running indoors. However, when it comes to common running injuries like plantar fasciitis or shin splints, the evidence is unclear.
“There are mixed feelings whether treadmill running reduces the risk of injury,” says Harrop. “The cushioning of the belt is thought to reduce impact and therefore loading injuries.
“However, your gait when running outdoors is more varied as runners change their stride length, cadence, and foot placement in response to their environment. Runners on the treadmill have less variation and poor form could lead to overuse injuries. To counter this you could use a mirror to monitor your form and correct errors, which was a trick used by the legendary runner Haile Gebrselassie.”
Are there benefits to simply being outside?
As the Instagram hashtag goes, outside is free, and saving your pennies is not the only reason to go outdoors for your runs. Both exercise and being outside have been linked to improved mood, especially if you suffer from mild to moderate depression, so heading out for your run can provide a significant boost to your mental health.
There are also physical benefits to outdoor running beyond that of what you get simply from the exercise itself, mainly in the shape of upping your vitamin D through exposure to sunlight. People in the northern hemisphere don’t get enough of this essential vitamin, to the point where the UK’s Department of Health recommends that adults consider taking a supplement. Moving all your runs outdoors, especially in the warmer months, can help your body get more vitamin D.
Outdoor running is usually more convenient as well, unless you have your own treadmill or live in a building with a gym. Sometimes that won’t be the case – when it’s sub-zero outdoors or raining cats and dogs the trip to the gym will seem like less of an inconvenience – but there’s an undeniable appeal to simply lacing up and heading out your front door for a run, rather than having to pack a bag and trek to the gym.
How can you make your treadmill runs more exciting?
Whatever your views are of the treadmill, every regular runner is likely to end up on one of them at some point. Maybe you’re travelling and find that the hotel gym is the only place you can run, or perhaps the pavements are so icy outside that it’s downright dangerous to attempt to run on them.
When that does happen, there are several things you can do to spice up your indoor run, starting with playing with the speed and incline settings. As Harrop mentions above, the treadmill is useful for speed work, because you can see the exact pace you’re working at, so using it for an intervals session is one great way to liven up your indoor running.
Hill workouts serve a similar purpose in being more exciting than a steady indoor plod, and can increase the strength of your legs. Most treadmills have preset hill workouts on them, so you can start them up and let the machine automatically adjust the incline settings for you.
It’s also worth taking some cues from cyclists when it comes to indoor training, because many riders move indoors for the winter and have developed a range of options to enliven their sessions. Training apps like Zwift, where you control an avatar in a perpetually-sunny virtual landscapes, can bring a digital version of the outdoor world to you indoors. Zwift is well-established among cyclists, who have to pay to use the service, but is currently free for runners.
The one piece of kit you need is a footpod that links to the app so it knows how fast you’re running, and how fast your avatar should move accordingly. Zwift sells its own footpod for $29.99, and third-party options like the Stryd running power meter are also compatible. After that all you need is access to a treadmill plus sight of a monitor, smartphone or tablet.
If you have a treadmill set up at home in front of a big screen, Zwift could revolutionise your indoor running. And if it doesn’t, well, there’s always Netflix. Now, there’s one big advantage the treadmill has over running outdoors – it’s very hard to catch up on Black Mirror while you’re running in the park.
Fancy buying your own treadmill?
If you’re paying for an expensive gym membership purely to use the treadmill it can be cost effective to pick up your own machine – if you have the space for it of course. If you primarily use the machine for walking or easy running you can get a decent treadmill for $300 to $500, and there are great home options for even experienced runners available for under $1000 though you will need to stray above that mark if you want a similar experience to that you’d get on the commercial-standard machines you find in gyms.
One of the key things to check when buying a treadmill is that the running belt is large enough to accommodate your stride. Compact, foldable machines might have a short belt that you find yourself falling off the back at, especially if you’re 6ft or taller. You should also look at how fast the treadmill can go.
Cheaper machines might top out at around 16kph, whereas gym standard units will go up to 20kph and above. Also check what incline it can offer – a maximum of 10-15% is useful, because adding a few percentage points of incline will make your indoor workouts far tougher without having to ramp up the speed too much.
Another important thing to check is the power of the motor in the treadmill, because a weak motor will mean that the machine starts to rattle and shake, or even turn itself off, when you run for long periods at the higher speeds available.
Look at the continuous horse power of the motor, rather than the peak horse power. It’s worth getting one with at least 2.5CHP if you’re a regular runner, while beginners and walkers should be OK with 1.5-2CHP.
What is a curved treadmill?
You may have wandered into a gym or studio at some point over the last few years and been greeted by sight of something that looks like a treadmill but has a strangely curved belt section. Although it may appear to be a treadmill it does have a number of features that make it considerably different.
Firstly, and most importantly, is the fact that a curved treadmill doesn't draw power via mains electricity. The shape of the device itself causes the runner to move the belt through the distribution of bodyweight. Initially, that's a strangely alien feeling but actually has a number of benefits, not to mention the environmental implications.
Because of the forward-leaning required to operate the belt movement, the focus of the movement is towards the balls of the feet – a style of running said to be more natural. Running in this way engages more muscles in the glutes and hamstrings than those generally incorporated into a traditional treadmill session.
Once you're used to running on a curved treadmill you'll find that due to additional forces involved and the upwards curve that you run on to gain speed, a workout will seem more difficult than on a traditional treadmill on a flat setting.
Another benefit to using a curved treadmill is the speed by which the belt stops and starts. From the point of jumping on you can start working out instantly without any need to turn it on and set the belt running. Stopping is also as efficient and the slowing down of the belt will happen as quickly as you stop running. It's for this reason that curved belts have become so popular in fitness classes that require short sprint intervals.
The added effort involved with running on a curved belt as well as the positioning of the body can make it less beneficial as a long-distance training aid, especially when you're focused on high mileage and low heart rate. But combining the two forms of training rectifies limitations in both forms of running.