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Running on a treadmill promotes muscle imbalances and hurts your ability to run in the real world.

I should probably lead off by explaining that I don’t particularly hate treadmills. I do however believe that the humble treadmill is probably one of the most misunderstood pieces of equipment in the gym today.

It is of course, hands down the most popular piece of gym or home equipment known to mankind.

However, successful as the treadmill might be at helping people exercise and catch up on Oprah or Ellen at the same time, it is not without its faults.

Used properly, the treadmill can be great way to burn fat and even works well for a getting the blood flowing before a workout. With it we can exercise any time of day, in any weather.

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Thanks also to this running technology we can take our workout indoors where our own HD surround sound media center ensures maximal distraction from the actual physical pain and distress of doing the task at hand. But don’t think that you are getting the same workout as if you were running outside…

Running on a treadmill is not the same as running outside or on a track

In fact, it’s not even close.

This picture and blog is brought to you by the letter ‘O’.

I think of treadmill running and running the same way dairy farmers compare cows milk to soy milk (I like soy milk, really I do – but it isn’t really milk, is it? But to be fair to the soy farmers, I might not be so keen to put it on my cereal if it was called ‘crushed soybean residue’ now, would I?)

Running on a treadmill actually develops imbalances in your running style and muscular development, which will lead to improper form and increased risk of injury.

Here’s why:

If you would, think briefly as to how the belt beneath your feet works.

If you place a foot on a moving treadmill it gets thrown back along the line in which the treadmill is moving – the treadmill is moving your foot back, not the foot moving itself back…

I will resist the urge to place a video here of people falling off their treadmills (although it was extremely tempting).

As you walk/run on a treadmill, the main difference your body experiences is related to the moving belt beneath you feet.

A treadmill moves you in a different way than regular running

Real world running

As you run in the real world, you are using a series of muscles combined with your momentum to create forward motion.

The crux of that last statement is ‘create forward motion’ – more specifically, your hamstrings and glutes pull back to drive your body forward relative to your planted foot in stride phase.

Whoah – I think I just accidentally channeled my college kinesiology textbook. Let me put that in terms my more-often-used primal brain can understand.

You use the back of your legs to help drive your body forward as you run. You propel from the back of the legs to keep yourself moving.

Non-Real world running

If I am on a treadmill, I no longer NEED to pull my body forward with the back of my legs. My left foot lands, the treadmill drags it behind me and I land the right foot before the left gets dragged back too far. I am essentially lifting the back foot forward then cushioning the impact with my knees without needing to pull the leg back (since the machine does that for me).

To simplify in a different way, we can break the lower body down into three major phases of a running movement:

  1. The impact on the foot on the ground
  2. The swing through of the back leg to the front
  3. The pulling back of the planted leg to drive the body forward and into the next stride

Here it is again with the major muscle groups being used for each phase:

  1. The impact (Quadriceps and Calves)
  2. The swing through (abs and hip flexor)
  3. The pulling back (hamstrings and butt muscles)

Starting to understand my sick and twisted mind? If you are with me so far (and kudos to you if you have managed to read this far down the post without falling into a state of catatonia) then you now understand why I believe this to be the truth:

When you run on the treadmill, the treadmill robs you of #3 (the pullback phase)

Where this really becomes a problem is when have been running on the treadmill for a while then decide on a nice day to go for a 5K jog outdoors instead… The result is a run that puts your joints and muscles into an exercise they have not been truly prepared to do.

Be creative with your cardio

So mix it up, people – or at least add some more hamstring work to your exercise routine. I am of course referring to the exercise routine that you say you are going to do but always end up running again on leg day because you don’t really know what to do and those sweaty jock dudes are always hogging those machines anyway.

No more excuses. Go work those hamstrings and butt muscles to balance out your overdeveloped quads and hip flexors! Need help with ideas? Get yourself a free introductory session with a personal trainer (or if you are really desperate, ask me).

Or just go running outside as much as you run inside. Hows that for a happy compromise?

Yours in health,

Jamie Atlas

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  • […] rest is here:  Treadmill Running vs Outdoor Running – Which is Better? The Debate … Share and […]

  • […] I should probably lead off by explaining that I don’t particularly hate treadmills. I do however believe that the humble treadmill is probably one of the most misunderstood pieces of equipment in the gym today. … More Iron Man Treadmill… […]

  • Strong One Mar 8, 2009 Reply

    I would say neither. No one is better or worse for you. There are OBVIOUS benefits to running outside as opposed to the treadmill, but each to his own.
    If the treadmill is where you can consistently go for your exercise, than more power to you.
    I think this is more of a benefit vs risk question. There is a lot more risk involved with running outside for the novice as opposed to the predictability of the treadmill.
    Thanks for sharing this!
    Great thoughts.

  • Mike Mar 18, 2009 Reply

    I have to agree, in general, that running on a treadmill is not as beneficial as running outdoors. Over the years my personal experience has been that it takes a conscious effort to correctly manipulate the treadmill in order to derive maximum benefit to your outdoor running. The biggest problem I see with using a treadmill is that people tend to use a flat or nearly flat setting on treadmill. They simply allow the belt to facilitate the leg movement as you have so ably described.

    However, it is possible to achieve an affect very comparable to road running if you make serious use of the incline feature of the treadmill. Setting an appropriately difficult incline will force you to use the hamstrings and the butt muscles in order to maintain your position on the treadmill and not find yourself being dumped off the back side because you fail to keep the necessary pace.

    So yes, I agree that for most people a treadmill can be a poor substitute for the road. But it is possible to get a very good workout and not short-change some of the muscle groups and the hamstrings in the process.

    So come on people, use the incline feature. You will be amazed at the difference that it makes.

  • […] Outdoor running vs Treadmill Running – which is better and why […]

  • Mark Jan 24, 2010 Reply

    Thanks for explaining it so clearly. I read it in other places and didn’t quite understand, but you laid it out very clearly. But you forgot about wind resistance, which is a big factor. I read somewhere else that the process you described accounts for 3% decrease in energy needs, and wind resistance for 5%, totaling 8% less energy needed to run on the treadmill. Setting the incline to 1% should make up for this margin.

    • jamieatlas Jan 25, 2010 Reply

      Ahh, great point Mark! Wind resistance (and environmental temperature, I guess) can play a big factor in running. Thanks for the insight! Of course, when you are 6’6″ like I am you know all about wind resistance anytime the wind changes – if only I could find one of those tear-drop helmets to make me run a bit more streamlined 🙂

  • shortslow Mar 9, 2011 Reply

    Thank you. I have been back to running for almost two years, and due to a micro stress fracture I was on the eliptical and now on the treadmill, too. I had never been on a treadmill… ever. I just like the going outside part. After 3 times on the treadmill, I just knew it was not the same, but could not figure out what was different. Your article demystified this in no time. This is so interesting!
    I will soon start my running outside again. However, I know that it will be harder. In the meantime, I am really becoming better aware of form on the treadmill because it is a new way to “feel myself” (ok… you know what I mean) in terms of awareness.

    • jamieatlas Mar 14, 2011 Reply

      thanks shortslow – if you get a chance to do any work with vibration training take advantage of it. It’s great for improving bone density and keeping things neurologically optimized – meaning your body will work better and run better for it.

  • […] will impact your joints, but running on grass is less of an impact than running on the treadmill. This website explains the differences reasonably well, but also check out this Sports Medicine post. […]

  • john May 27, 2011 Reply

    what about an incline in the treadmill you didnt mention that that would give you the thrust forward in your hams and glutes

  • Anurag Sharma May 31, 2011 Reply

    I took outdoor running after I got tired of running on the treadmill. I wanted to lose fat on the face and my uncle who is a retired sports person, advised me to run outside to achieve a tonned face. I followed his advise and achieved a toned face in a month by running upto 3 KMS daily. Nothing like running outside!!!!

    • jamieatlas Jul 24, 2011 Reply

      Didn’t think about the toned face Anurag – if it’s worked for you then that’s great news! Saves me the money on my next botox injection, which is great! 😉

  • Fernando Jul 21, 2011 Reply

    This article is such BS.

    Treadmills can be every bit as hard as running outside, it’s up to you just like anything else. You forgot one crucial factor in your “expert” assessment, the same energy that propels you as you run on the treadmill is absorbed when you land, which equals it out.

    And none of you, NONE of you, will make it to the age of 50 without some kind of joint complication if all your running is done on pavement.

    This type of people ‘hate treadmills’ just like they ‘hate cats’ just because they have dogs, it never shows much reason.

    I lost 30 lbs in one year, safely, by running on a treadmill every day. Why? Because I never had a single excuse. So I know EXACTLY what I’m talking about.

    You like running outside? Run outside and shut up.

    Then try running on a treadmill at an incline and see if you can keep up.

    You won’t.

    • jamieatlas Jul 24, 2011 Reply

      Hey Fernando – appreciate your feedback as I do all feedback 🙂 The energy may be absorbed as you land, but that is constant whether running on land or on a treadmill, is it not? I think it’s fantastic that you lost 30 lbs in a year by just running on a treadmill – who knows what kind of results you might have gotten doing it outside – and on what science are you basing your ‘running on pavement ruins your joints by 50″. By that logic, wouldn’t some of the ultramarathoners be in wheelchairs by now? Keep on running though mate, glad you are enjoying it and are obviously passionate about it.

      • Kyle Oct 15, 2011 Reply

        No worries, Jamie. Good points…I agree with what your article said. Physics is not an intuitive subject and you cannot expect everyone to understand scientific thinking. I just tried a treadmill today and suspected that exactly what you were saying in your article was the case and that led me to research whether or not that was, in fact, true. Treadmills seem to (on the flat setting) exercise purely vertical force generating muscle groups, whereas running on ground (trails, woods, road, etc…) requires roughly equal vertical force AND a significantly larger horizontal force component. Am I getting your point?

      • Jessica Feb 2, 2012 Reply

        But Jamie, now you do exactly what bad trainers do. You set up a false dichotomy and you disparage the results someone had by demanding they do it your way without knowing if your way would fit that person. You, yourself, often stress that there is no one size fits all in fitness. Granted, the post you are replying to was confrontational and aggressive and that may make you less inclined to respond civilly or think about your answer but the passive aggressive “imagine the results you might have had, had you done it my way” is really counter productive. If he had done it your way, he may have stopped after two weeks and never taken it up again. Surely X exercise is generally better than 0 exercise?

        Everyone doesn’t have the choice to run outside. Or the choice may be seasonal – in Sweden, where I’m from, dawn is at 10am-10.30am and dusk is around 3am for a large chunk of the year, many areas are not safe after dark and people have jobs that keep them occupide for the only sunlight hours. Surely they shouldn’t stay off the treadmill because you deem an unobtainable outdoor run to be better for them?

        Or someone might need to start modestly because they start out really out of shape. If feeling a resistance to get going, left to their own devices many people fail to keep up the speed in an outdoor run. The treadmill sets the speed for you and you can increase both incline and speed gradually until you get a muscle memory how fast you actually have to move to run at Xmph. Something you can _then_ take with you outdoors – if you have that opportunity – and then get the increased benefits of increased resistance. I mean, by that logic you should only ever do running on the beach since that increases resistance even more. Don’t live where there’s a beach? Well, then get one? See how that doesn’t quite work.

        I assume Denver has a lot of great outdoors to offer but not everyone lives in places like that. The woods where I grew up would have 7ft of snow for about five months of the year and only car lanes were kept clear. Jogging there would have been begging to be run down by a truck or doing a salto and land on your head. We did other stuff instead, like skating and cross country skiing or pushsledding – because this was a couple of years before everyone had treadmills in their homes – but the point is that no one would have been running during this time. If running (actually, most were into orienteering) was your gig you would _have_ to find a gym with a treadmill for winter training. Maybe that affected your form, for when the snow melted away, badly but surely it was better than sitting on your bum, waiting for summer?

  • Marek Jul 24, 2011 Reply

    Nice article, but… have you ever attended in a physics class? The treadmill “pulling back” or outside “pushing forward” is just a question of selected background system. Imagine yourself running in a moving, really-really long bus. It is the same thing with treadmill.

    • jamieatlas Jul 24, 2011 Reply

      Hey Marek – I’m actually a neuroscience major from way back, so yeah, physics is something I’m pretty familiar with. However, the bus you’re referring to might influence the system if we were say, moving at the speed of light, but not so much in this background system. Whether I’m on a bus or on the ground, the ground underneath me isn’t moving backwards at a rapid pace. Maybe if you said the really really long bus was driving backwards as I was running forwards on it, then yeah, I agree – and in that situation I’m pretty sure my principles still apply.

    • Kyle Oct 15, 2011 Reply

      When you run on a treadmill, the belt pulls one foot backward and you really only have to bounce upward and swing your other leg far enough forward to land in such a position as to stay where you are. When you run outside, you are generating all of the forward driving force. I am not arguing that you generate NO horizontal force on a treadmill, but running outside requires much much more horizontal force than that. That is the difference I think Jamie is referring to. Due to carryover effects and strongly subjective measure, it is unreasonable for me to suggest running an 8 minute mile on a treadmill one day and then doing it on a flat track the next to compare, but if it could be done objectively and with strong experimental control, I’m betting the outdoors mile would exhaust to a much higher degree than the treadmill mile.

      • jamieatlas Oct 15, 2011 Reply

        Thanks for the comprehensive reply Kyle. You’re right on track with your assertions. It’s objective to a point – the even more interesting question is would you work harder or easier running on a trail because a trail would have a harder surface (possibly) than a treadmill, and as such the body would not have to create extra ground forces to try to propel the foot off of the softer spongier treadmill? Buuuut that’s another post in itself 🙂

  • Anon Aug 3, 2011 Reply

    Great article. I never even thought about that. I still like the treadmill more though. With a treadmill I can make myself run at a press of a button. If I didn’t have the buttons I would have to rely on willpower to motivate me, and I have none. So I guess I’ll just have to work those other muscles separately.

  • Rachel Aug 14, 2011 Reply

    I just completed a couch to 5K training program on the treadmill. Two weeks into running 5K on the treadmill, began to have groin pain and some of my groin tendons popped out. So, now I have tendinitis and muscle tearing in my groin. Wondering if running outdoors would have resulted in the same injury? I really miss running – now I have to take time off to heal the injury.

  • Nikhil Mysore Oct 13, 2011 Reply

    Firstly, I would like to appreciate the article. It was very convincing and really informative.
    What I would really want to know is if running on the treadmill is safe for me? I had torn the ACl of my left leg an year back and since then I haven’t gotten back to running outdoors (although I manage to jog). I started running on the treadmill some 2 months back and as mentioned somewhere I can feel my quadriceps growing stronger. But at the same time I feel some pain at my shinbone. Also I have heard that running on the treadmill has severe impact on knees. Is it true?

    Should I continue running on the treadmill which will strengthen my quadriceps or should I go outdoors and keep my knee intact?

    Oh and I should also mention that I haven’t recovered completely, yet

    • jamieatlas Oct 15, 2011 Reply

      Hey Nikhil – I’d advise stopping off at a high end running store and getting an assessment and some new shoes. Then do some research on different running techniques to figure out what might be easier for your body. Some people prefer a heel toe style, others a midfoot first… explore and discover… feel free to ask me questions here if you get confused along the way 🙂

  • ramblinknight Oct 20, 2011 Reply

    I’m not sure I buy this argument and here’s why.

    Imagine you are on a really long moving sidewalk (like at a big airport) and running in the opposite direction. I would consider this the same as running on the stationary ground but also the same as a treadmill. A treadmill is really just a very short moving sidewalk.

    Running on a moving sidewalk is just like running on the ground because planet Earth is moving. It’s just that it’s not accelerating so we don’t feel it. Similarly a treadmill and moving sidewalk is not accelerating making them all the same.

    Let me know your thoughts. I’d like to figure this one out.

    • ramblinknight Oct 20, 2011 Reply

      I’m trying to research this elsewhere and have heard varying opinions. I’d like to propose a new reason why a Treadmill may be different (from a physics perspective).

      Relative to a fixed point on Earth, gravity always points down (to the center of the Earth). Relative to a fixed point on the treadmill belt that is moving backwards, gravity is pointing at an angle that is down AND forwards.

      This means that gravity is actually helping you slightly on a treadmill relative to running on Earth.


      • jamieatlas Oct 20, 2011 Reply

        Hey mate. Okay, so after much thought, the angle at which an object would be pulled forward aaand down would be negligible since you would still be the same distance from the center of the earth. Gravity is always pulling me at the same acceleration regardless of how fast or slow i might be travelling. Much like a piece of rock tied to the edge of a string being spun in rotation. Regardless of my speed, assuming distance to the center remains same then the force drawing me in (eg gravity) remains the same.

        Make sense?

    • jamieatlas Oct 20, 2011 Reply

      Hey mate – interesting question.. makes me hope my physics professor isnt reading this for fear i get it wrong…

      I agree with the first paragraph – with the exception that you need to match the opposite speed of the walkway to remain in one place (so as not to fall off)
      Running on the ground is different because even though im running the earth is moving with me – if the earth were supersmall (imagine someone walking on a ball that was rotating on an axis) then that person would be forced to walk in order to not get thrown off or knocked over.

      Running on a moving sidewalk is very different than on the earth because the relative velocity is different. That is, i need to create a speed to not get knocked off or to stay in the same place. I can stand still and the earth would still move with me.

      How does that feel to you?

  • BERT Nov 14, 2011 Reply

    all I know is I have been running on the treadmill for 9 months 4miles
    2-3 times per week and when I finally started running outside I was exhausted after 1 1/2 miles. Keeping a pace and forward motion is all the difference in the world.

  • Daria Nov 17, 2011 Reply

    This is the best explanation I’ve ever heard/read. I am a new runner, who started on a treadmill and had such a hard time running outside and I could not understand why (I was going faster, longer on the treadmill than I did running outside)
    I’m in process of training for my 1st half-marathon and without questions I take it outside

    Thanks again.

  • […] Fitness Insight by Jamie Atlas […]

  • Herc Dec 14, 2011 Reply

    Hypothetical question:
    Its obvious that when running outdoors, you do not have the “benefit” of the ground artificially moving itself underneath your feet as you would running on a treadmill. But on a treadmill, your body is stationary, which robs you of the “benefit” of momentum. (“Benefit” in the context im using it here relates to making the work easier to do)
    That being said, if your running correctly on a treadmill, meaning youre actually feeling the hamstrings, glutes, calves, etc propelling yourself “forward” and youre not simply bouncing up and down on the moving track beneath you, its hard for a logical person to reason that its much different from running outdoors. Especially when the treadmill is set at a moderate incline and one is running at a moderate speed. I feel if the last two criteria are not met, treadmill work is indeed much easier than jogging outside is. One other minor “benefit”of to treadmill work is the lack of wind resistance. Everyone should keep in mind that “benefits” in the context of this reply are actually drawbacks to those looking for more effective training/exercise programs.

  • Barkae Jan 1, 2012 Reply

    I agree. I moved to a hideously cold climate with snow and ice. So I purchased a very expensive treadmill. I have been running almost 20 years and it only took 2 weeks for me to be in so much knee pain that I almost could not even WALK on the treadmill.

    This was very very distressing because I need to run. I tried Stabalizers, but they do not work where people have shoveled the sidewalk! Something that comes very close is walking in hip deep snow. That really maxes you out. But nothing is like running.

    So there is no solution in an icy climate. I got hurt running in ice once, trying to avoid a patch and tripped on hidden debris under snow.

    This has all been a big factor in a move out of the crazy winer weather.

  • Dougg Jan 13, 2012 Reply

    On the treadmill you have to keep the same speed that would be one plus right!

  • […] to Jamie Atlas, when you run on a treadmill, you are not actually experiencing running. With the belt moving under […]

  • lee williams Feb 2, 2012 Reply

    I think you make a very good point about treadmill training, but I know that by using my treadmill once a week for a hard session it has improved my 5k and 10k times quicker then when I didn’t use it. Thanks for the information though it was interesting to read.

  • Serge Feb 9, 2012 Reply

    Really appreciated the article. 🙂 answered a couple thought I was having when I swiched off the treadmill. I think those who hit the tread mill should try running outdoors and share there experience. In response to the joint comment… your bones modify to the pressure exerted on them wolffs law.

  • eye of odin Feb 18, 2012 Reply

    I totally removed my self from the gym in favor of the outdoors. Ever since i realized that real world strength and functionality is where its at! My roommate is a gym rat and spends hours a day at the gym doing cardio on the treadmill and using every machine known to man there. I finally convinced him to jog from my house to the gym, only a short 15 minute jog for the average Joe. Well low and behold he did it once and complained the whole way! He is not capable of doing real world running but can kill it on the treadmill? He is also not able to run more then two fifty meter flat track sprints without crying mercy. Well we will see when i am in my 80’s and still able to function where the gym rats will be at? Heavy lifting and and artificial movements will hurt u Im the long run i have no doubt!

  • tryingtogetfitgirl Feb 22, 2012 Reply

    Weeellllllllll!! I’ve been running on a threadmill for 20/25 mins 4 times a week for the past few months at a good pace on a small incline, working up a good sweat and generally getting out of breath, have also done other cardio ‘leg’ stuff, fast walk on a steep incline and rower/ bike. Car broke down this week so I thought ok, will run to work, is about a 25 min run some hills, some pavement, some soft ground. Third day in could barely move my legs! Have very obviously used different muscles, thighs and calfs hurting, walking in a very odd manner after any time sitting down! I;m gonna mix up from now on, run to work 3 days, threadmill 3 days.While I won’t pretend to understand the science behind it I can say for sure that different muscles are used. What I would say is that I felt I ran faster on the threadmill & sweated more, but was more out of breath running outside, any ideas why??

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