My Scientific / Personal Advice for Treadmill Training


Every year one of my New Year’s resolutions involves running. But I really don’t like running outside in January when it’s cold.

So, instead, I run on a treadmill as does our entire family. (That’s our daughter, Kellyn above). I’ve been enjoying running on a treadmill over the winters for more than a couple decades. In fact, to the chagrin of trainers and coaches who would advise otherwise, I once trained for a marathon, running exclusively on a treadmill. Yes, we could choose other forms of indoor aerobic exercise to get in shape. But colleagues of mine (also physical medicine and rehabilitation physicians) published this seminal research study in 1996 showing that the treadmill, compared to other forms of indoor exercise equipment (stationary bike, rowing machine Nordic Track, etc.), is the most efficient form of aerobic exercise. Specifically, they found that at the same level of perceived exertion, you burn more calories per minute on a treadmill than on any other type of indoor exercise equipment. A beautiful study, it has certainly guided our family’s routine.

Supported by the National Institutes of Health, I spent a great deal of time researching the biomechanics of treadmill walking and running. My research team and I published the definitive and most cited research studies here and here on the biomechanical similarities and differences between treadmill and overground walking and running, respectively. Our research has helped dispel pseudo scientific comments made about the treadmill such as “the treadmill belt propels you forward so that you do less work,” or “the treadmill belt pulls your leg through, resulting in a relatively passive extension of the hip, which reduces conditioning of the hip extensors.” Comments such as these often made by well meaning trainers and coaches are unfounded. Whether you’re moving over a stable base or the base is moving beneath you, the relative motion is the same, amounting to the same biomechanical conditions. Meaning that your hips, knees, etc. all move the same and that you’re working all the same muscles.

Now there are a couple differences between treadmill and overground running. The first is that in treadmill running, you don’t need to displace the air that is in front of you so that at a given speed it’s a tiny bit easier to run on a treadmill. Many will tell you that to make up for this difference you need to set the incline on your treadmill to 1%. But there’s no science out there to support that you have to. Granted there was this study that showed that running at a 1% incline takes the same amount of energy as running at the same speed outside on level ground outside. What many people don’t realize is that in that same study, there was no difference in energy between running outside and on a treadmill with 0% incline for speeds up to 7.5 miles per hour (equivalent to a 8 minute mile). In any event, if you feel like it’s easier to run on a treadmill, all you have to do, is increase the speed. If you end up running at a pace that’s faster than your usual outdoor pace on a level flat surface, just think of it as a needed winter confidence booster.

The second difference is that a treadmill offers a certain amount of compliance or springiness, which helps to reduce the peak forces through the joints and other injury sensitive areas of the body. The springiness that a treadmill provides is very different than the typical foam in a traditional cushioned running shoe sole that actually increases, rather than decreases, peak forces through joints, as we showed in this study here.

So, let’s proceed with a few tips beyond the usual “consult with your physician” “and “progress slowly, increasing effort by no more than 10% each week,” that applies to any form of exercise.

Don’t hold on to the handrail or console. Not only will you get less of a workout, holding on compromises your natural biomechanics. The handrails are there only to help you safely get on and off the treadmill. I’ve often been asked if it’s okay to hold on if you have an injury in your leg or foot. My answer to that is “no.” It’s very difficult, if not impossible, to unweight yourself at just the right time that would avoid placing undue stress somewhere else in the body. Believe me (and our research) that it would have to take a sophisticated computerized feedback-controlled unweighting device to correctly unweight oneself during walking or running.

Set the treadmill to “Manual.” That is, don’t fuss with the fancy programs that are often available on a treadmill. This gives you more control in how much you push yourself. Basically, you want to listen to your body (as you would when running or walking outside), not the machine.

Set the incline to 0% and don’t be compelled to increase it unless you would like to. Personally, I never use incline on a treadmill. Mainly because it confuses me as to how hard I’m actually working. But also because of this seminal study here that we did showing that there are no clinically significant biomechanical differences between running on a moderate incline, level, or decline treadmill surface. That is, the peak stresses on your knees and your other joints are the same whether you run on an incline or not. Moreover, incline is an added variable that seems to be very inconsistent between different treadmills. The reason for the variability lies in how the treadmill is mechanically jacked and supported when in an incline position. Depending on the quality of the treadmill, the incline mechanism affects the stiffness of the treadmill surface and can sometimes introduce vibrations, which makes things even more confusing. I like to know exactly how much work I’m doing. And altering just the speed allows me that opportunity.

Running on a treadmill offers an easy opportunity to figure out your stride cadence, that is, the number of strides you take each minute. A stride is the interval between when one foot touches the ground and when that same foot touches the ground again. A stride encompasses two steps with a step being defined as the interval between when one foot touches the ground and when the other foot touches the ground.

All you need to do to determine your stride cadence is count how many times the same foot touches the ground in one minute. Your stride cadence should be 90 or above. If it’s any less than that, you’re overstriding. That is, you’re taking longer strides than what’s physiologically normal. Overstriding imposes excessive forces through your joints, bones, and tendons. Bottomline, you don’t want to overstride, but understand that most people accustomed to running in traditional cushioned running shoes, unfortunately do. Traditional running shoes cause an unnaturally long stride that imposes excessive forces through joints, bones and tendons. Wearing OESH that are perfectly flat from the heel to the toe can get your stride and your cadence where they should be. If you still have a pair of traditional running shoes (which I hope you don’t!), try comparing your cadence in them compared to when wearing OESH. You can also try using a metronome to improve your cadence.

Listen to music! Listening to songs that have a good strong beat (think Rock and Roll!) has been nicely shown in this study to improve motivation. While I strongly discourage listening to music while running outside on the streets (headphones make you oblivious to cars, bicycles, and other potential dangers), I’m all for cranking it up when on the treadmill. As long as you refrain from trying to actually dance while running, you should be safe. I keep about 50 songs that I especially like in an iTunes library called “Running” and play them in sequence, picking up from where the sequence left off the workout before. I edit the library from time to time but some of those ‘80’s hits that have a good strong beat, have managed to hang on for quite awhile.

Don’t be afraid to explore other things that may motivate you. Science will catch up in demonstrating that certain things are better than others in keeping people motivated. But in the meantime, you can experiment on yourself. For example, you might like watching TV. I’ve never liked watching TV at the gym (even when it’s built-in to the treadmill – I find it too distracting) but this year, for Bob’s birthday, we got him a projection screen TV that sits in the vicinity of our home treadmill. The TV is perpetually set to Bob’s NFL football station but I found that if I go up just one station I get a channel called “Create” that has things like cooking, traveling, and home repair projects. I don’t listen to the sound, just watch, which is the perfect amount of distraction, for me at least, while running.

I don’t like keeping constant track of how far or how many minutes I’ve gone while I’m actually running so I either keep my eyes off the reading on the console, throw my towel over it, or change the reading so that some other parameter is front and center. Of course I do check now and again as the last thing I want to do is run a hundredth of a mile more than I set out to run.

That’s it. Running on a treadmill is a great way to either get into or stay in shape during the winter. It’s so great in fact that you may find you like running on a treadmill year-round. That is perfectly reasonable and I know many people who do that. But personally I feel if I ran on a treadmill year-round I’d lose some of the excitement of running on it during the winter… sort of like setting up the Christmas tree in June. But that’s just me.

47 Responses to My Scientific / Personal Advice for Treadmill Training

  1. Russ Egeland says:

    Very enlightening article. I’ve used treadmills for winter months and assumed many of the debunked myths were true. I have recently tried doing a short part of my workout experimenting with running sideways and backwards, but initially at very low speeds (e.g., 1 mph), or slower.

    I think this is a good thing at slow speeds to exercise sideways motion muscles, especially hip flexors, and backwards (a la Yul Brenner’s routine to minimize back pain during his dancing routine on Broadway for the King and I). I feel those muscles wearing out quickly so I basically go around in a circle a few times, 30 seconds facing right, 30 seconds facing backwards, 30 seconds facing left, then right, then back…for several times.

    Is there a benefit or harm in doing this type of routine. I typically do it after my regular treadmill run.

  2. Scott says:

    Thanks for the great article in your blog on treadmill and road running differences.

    What about the difference in landing (loading force) mostly on the quads, that you get when road running?

    I’m not an engineer or scientist but isn’t there a law of motion that states, the faster you’re moving, the more energy/ force is generated which is then absorbed by the landing (muscles) on one leg?

    Since there is no actual forward motion on a treadmill, the landing force would stay the same and be much lower than moving at say 8mph. The muscles would be working progressively harder absorbing this force and converting it to forward motion as you go through the stride and move your body weight forward.


    Scott Bias

    • Casey says:

      Good thoughts but it’s actually your relative motion to the treadmill (e.g., 8mph), not your forward motion (which is zero), that determines the forces. More specifically, it’s the stride length (related to speed via cadence) that most directly determines the magnitude of these forces. That said, there IS a difference in forces when running on a treadmill versus overground (forces are less when on a treadmill). But that difference is due primarily to the additional compliance or springiness in the treadmill as well as a slight reduction in stride length on the treadmill.

  3. Theresa Guise says:

    Great stuff, Casey!

  4. Sherry says:

    This is such a breath of fresh air. I am a treadmill lover and have mine set up to face our backyard, so I can watch squirrels and other creatures while I run. I am no stranger to long distances on the treadmill and have also trained for a marathon almost entirely on a treadmill (23 miles was my longest). I listen to music, radio programs, and often nothing at all.

    I have always thought that treadmill training was the same for my body as running outside, and I do set the incline up a teeny bit, but not always, and do find myself running a bit faster on the treadmill. It’s also often significantly more pleasant, so it is very refreshing to read your blog and these studies that back me up. Thank you!

    • Casey says:

      Your welcome. And thank you for sharing your experience!

    • Ed Targonski says:

      Thanks for this. I am also primarily a treadmill runner and have done the majority of my race training on it due to life circumstances. I’m glad to read that I am not the only one who does this and feels like the prep is sufficient.

  5. Jason says:


    Interesting post, and maybe it means I can lower the incline on the treadmill. I’ve normally followed or approximated the guidelines in Dr. Jack Daniels “Daniels Running Formula.” The book includes a table that approximates output based on incline and speed settings of the treadmill. Most of the incline settings are greater than 2%. Are you familiar with the table and what do you think of its usefulness? Do you feel your research reveals that the extensive table isn’t necessary?

    Note, before my exposure to Daniels’ RF and the table, I used 1% as the norm for setting the treadmill — and used treadmills extensively on deployment as a principal means to stay in shape, running up to 10 milers on the t/m — certainly appreciate good research on this topic.


    • admin says:

      Jason, I did not know about Daniels Running Formula but just found it and my impression is that the incline recommendations are overly harsh although it does include speeds that are much higher than for the 1% incline study. I would stick with what feels right to you (whether that’s running with an incline or at a faster speed on the treadmill) knowing that any given study is going to be subject to variation depending on the subjects’ level of comfort running on a treadmill versus overground (which can affect stride length among other things), the compliance of the treadmill, incline mechanism stiffness, etc.

  6. Joe Mazzola says:

    Does running on a treadmill with an incline produce more of a work out than running on a treadmill with no incline?

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  8. Scott says:

    How about sharing your treadmill playlist? Back in my high school track and cross country days Ted Nugent always provided that extra boost!

    • Casey says:

      Let’s see…right now I’ve got Abba, Go-Go’s, Madonna, Michael Jackson, the Cars, Tina Turner, Dire Straits, Maniac (from Flashdance). Yes, I admit, mostly hits of the ’80s with a few newer things now and then…I think you’ll get a kick out of this post!

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  12. Shyamal Kapadia says:

    Could you comment on studies which show difference in energy expenditure on treadmill vs. overground running in regards to cooling oneself, especially over many minutes or hours of continuous exercise?

    Thanks much.

    • Casey says:

      I’m not aware of any published studies looking at the effect of cooling specifically. That you’re not displacing air on a treadmill theoretically could make it more difficult to dissipate heat from the skin when on a treadmill but then there’s the variable of temperature as well.

  13. JP says:

    Great post, great info. I have a question. As you have adequately debunked the 1% myth, which I had been sticking to religiously as I always seem to run slower yet exert more energy outside compared to on the treadmill, is there no benefit to running on an incline versus flat? Does the incline not create some form of resistance than helps to increase leg strength and improve form? Akin to a baseball player practicing their swing with a weighted donut on the bat, thus their bat speed without the donut is faster. Or is a 1% incline not significant enough to gain these benefits? I know I can do hill repeats as well, but that’s something, unless i’m mistaken, should only be done once a week, and only after a good base of miles has been accumulated to prepare one for speed/strength training.
    One thing I do love about the treadmill is that it requires more effort to slow your pace down. With outside running you just have to think it, where as on the treadmill you have to make the conscious decision to reach up and actually push the speed button(s) to slow yourself. Thanks again for your research, results, and sharing them with us.



    • Casey says:

      As even a 4 degree incline failed to produce significant biomechanical changes compared to a 0 degree incline (as we showed here“>here) I think that even if there IS a difference at a 1% incline, I don’t think it’s significant enough to count on for gaining an additional resistance training effect.

  14. Sloeginrunning says:

    Good post reinforcing the need to actually read the study, which has been shorthanded to 1% incline = outside, when you rightly point out its more like 1% = outside when going faster than X (X being somewhere between 7:09 and 8:00). I presume though that the impact of air resistance is a continuim, that the effect diminshes but never disappears, just becomes less important the slower you go. Also it seems like the the longer your run is, the more important this difference would be because it would add up for a bigger difference over a longer run.

    I will continue to use 1% largely based on the goal of equalizing effort to outside, espcially for tempo or intervals where hitting a specific pace/effort is more important. I will say the links to this post though seem to swing too much the other way that, incline doesnt matter at all, which is true only if your goal is a slower run.

    I also have read some analysis that the difference between outside and treadmill effort is attributable to the cant of the road/sidewalk/paved trail to account for drainage. In essence that outside (absent a track) you are never running on a completely flat surface and that difference is meaningful. I am not sure that is right because over the course of the run the difference would be too slight, but I am interested in your thoughts on that.

    • Casey says:

      I think the cant indeed does slightly alter one’s biomechanics and increase energy requirements. The actual amount to which it actually does, however, has not yet, to my knowledge, been formally studied.

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  18. Ganeeban says:

    Finally! A real answer to this question. I’ve always set the treadmill at 2.0, but I have no idea what it even means. I assumed, like many others, that this was somewhat equivalent to outdoor running! WRONG! Thanks for sharing, I will pass this little myth buster along…

  19. Robert Braun says:

    Have you seen the Elliot & Blanksby study on differences in stride length between running outdoors and on treadmills? See

    Do you think think stride length has an impact on whether the incline makes a difference?

    • admin says:

      Indeed, that was one of the older (1976) motion studies we referenced in our treadmill versus overground kinetic study. Like other studies done before ours, it did not include force plate measurements. And yes, I believe stride length independently influences the magnitude of the ground reaction forces and joint torques, in many (not just incline, decline) conditions.

  20. Jan Udlock says:

    Oh my goodness, Casey, I’m so excited that I found your blog. I’m a 55 year old who has signed up for my first (hope to run) 5K in April. I’m using Couch to 5K but I ran/walked my first week and feel like I wanted to give up. It wasn’t because it was super hard…I didn’t know why I just didn’t want to do it…And your blog helped me see that I thought I wasn’t “really running” because it was on a treadmill! I have bookmarked your blog and will come back and read through it.

    I am so thrilled to see that running on a treadmill is really important, healthy and it is running! Yay, yay, and YAY!

    • Heather says:

      Jan, I trained for my first 5k on a treadmill too. It definitely helped improve my endurance and taught me to override the part of my brain that said “I can’t”. However, it took me several runs outside to get the same tolerance to outdoor running. You can certainly train for distance on a treadmill but I would also make sure you do a few outdoor runs before your race just to work out any differences for yourself….. Whether they be physical or in my case, mental differences. Good luck!

  21. A.K. says:

    Which brand is the tread mill in the photo? Did you do a lot of research before you bought one?

    • admin says:

      It is a 1993 Trotter 535 Treadmill (Trotter was since bought by Cybex). We’ve overhauled it three times, once replacing the motor and twice replacing the deck, but it still keeps going strong. If we had to get a new one, I’d stay clear of any advertised cushioning system that attempts to cushion the front of the treadmill while keeping the middle of the deck firm. The simple, traditional design with a plywood deck where the front of the deck is firm and the middle is the most compliant, should be the easiest on your joints, offering compliance when and only when the forces through your joints are at their greatest – not at “impact” but rather in mid stance when your weight is fully planted on your foot.

  22. Justin says:

    What about the bio-mechanical changes in a graded exercise test, have you had any research on that? I do a lot of lactate threshold testing using both treadmills and cycle trainers. On a bike the subject can just cycle at a given cadence regardless of the resistance so mechanics do not change it just gets harder. On a treadmill though the stride length/pace is altered every stage because of the treadmill speed adjustments. I can progress someone through a test and see the mechanical changes which the subject sometimes complains about saying it feels unnatural or uncomfortable being “forced” to go a certain speed. If these changes are having a large impact in muscular force production or muscle activity then it could be skewing the lactate threshold test results by increasing anaerobic energy contribution. My question then is, do you think that treadmill running at different paces in a GXT could cause large enough differences to prematurely see a threshold in some subjects?

    • admin says:

      In running, since the grade only minimally affects the mechanics and is much more variable anyways, I would suggest for testing purposes, relying purely on increasing speed. I’d also suggest that you encourage the same cadence (approximately 90 per second) to further reduce unwanted variability. Maintaining the same cadence might also help a little with some of that “unnatural” or “forced” feeling but I fear that that is the nature of the beast of treadmill running… the ground is moving under you and you are forced to keep up.

  23. Tori says:

    Thank you for this article! I am a distance track runner and as the weather goes for a turn during the winter, I don’t enjoy runs outside in the cold. It’s just tourtue and I always end up sick the day after. So I was looking into buying a treadmill to keep me in shape till spring track starts up again, but with all these treadmill myths I’ve been having mixed feelings. My coach said running outside is better, but I just need to run. I can’t go a day without running, as if it’s a blizzard outside I’m screwed. So with a treadmill, that will never be a problem for me. Now I know that I can still stay in somewhat shape from the time winter track ends to spring track. Do you have any recommendations on treadmils good for distance runners? There are so much pricey ones to chose from. Anyway, thanks for boosting my confidence during the winter and bad weather!

  24. Hi Casey: I have always read that ground reaction forces are not the same on a treadmill making them less beneficial when trying to emulate running or walking in thr real world. I would appreciate your comment

    • Casey says:

      Hi Woody. It’s long been assumed that the ground reaction forces are different on a treadmill but our studies (cited above) were the first to actually compare the ground reaction forces between walking and running on a treadmill compared to overground. As noted, counter to what had been long assumed, we found very little differences.

  25. Mike H says:

    Great blog post. Very informative. I have run on my treadmill in the winters on and off for nearly 15 years (same treadmill – minor maintenance but a great machine). Others may have commented on earlier posts but wanted to pass along that I have a TV mounted on the wall about 5′ in front of the deck and a great pair of remote headphones. Allows for great AM workouts with a world of Netflix and iTunes content that doesn’t wake up the HH. Also allows for watching TV shows that my kids do not need to see just yet. I’ll bookmark the site and check back. RW provided the referral. Love finding new information about this great sport.

  26. Stephanie Collins says:

    Just curious, what do you say to all the parents who jog / run holding onto a stroller? I know LOTS of them who have been doing it one child after another for years with NO physical ailments. Granted it is not a treadmill, but same principal as a handrail. The only thing I’ve heard from all of them is you do not hold on with two hands, an you switch hands every so many steps.

    • Casey says:

      The main thing about running with a stroller (in which I too have a good 10 years’ experience with no physical ailments!) isn’t so much the holding onto the stroller as it is the lack of arm swing. Arm swing serves to minimize the up and down displacement of the body’s center of mass, making it easier to run. Lacking arm swing doesn’t seem to affect the lower limb biomechanics; it just makes it harder to run. Holding onto the stroller with just one hand allows at least the other arm to swing and minimize the center of mass displacement, which is easier (and more enjoyable) than zero arm swing, but because of the asymmetry associated with that, indeed, I think it’s a good idea to switch hands every now and again.

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