How much easier is a treadmill?

Sorry moleman and walter, your arguments are unsupported. Physics whiz is correct.

1. Show me the mechanism by which your feet are "propelled by the belt" in a way that a road doesn't. (I assuming you are not holding onto the handrails!)

2. There is no appreciable change in vertical or horizontal components. You are not simply jumping up and down on a treadmill. If you're moving at 10 MPH on the ground you are applying a certain force to propel your mass forward at that velocity. Asssuming you are keeping the same stride rate, you must apply that same force on the treadmill or you will eventually fall off the back.

3. As a "science guy" I have always been interested in quantifying things. I HAVE compared HR monitor readings and other types of workouts on the track to the treadmill. As I stated, once the treadmill is calibrated and the wind resistance corrected for, I found the correlation to be spot-on.

You guys need to take a physics course. Science is good.

oldguy wrote:

There is a lot of information out there on this topic. The bottom line is that running on a treadmill at 0% grade requires considerably less energy than running forward on flat grounds.

Everything I've seen is a theoretical calculation based on reduced wind resistance. I've never seen anything where they actually monitored people running on a treadmill and then monitored them running the same pace not on a treadmill. Running is too complicated a process to believe much of anything based on theoretical calculations.

I think the most likely explanation of why that guy found running on a treadmill so much easier is that it was calibrated incorrectly. Just like race courses, treadmills that tell people they're running slow get complaints and get fixed. Treadmills that tell people they're running fast don't get complaints and don't get fixed. That's why there are many more treadmills (and race courses) that are "short" than there are ones that are "long."

I spend a month running on treadmills when i had no trails around....no body in their right mind can tell me its easier to run on a treadmill at least for me....with no incline at all whatsoever i can barly keep 7:30 pace going for 45 minutes...you put me on the road and i can do 6:30 pace for an 1:30 easy as anything....treadmills are hard as crap no matter what the educated people on this bored say...i think alot of other factors are magnified when doing a treadmill which make it harder....BORDROM IS NUMBER ONE...and also i dont know what gyms ya'll guys go to but they keep the gyms where i'm at at about 75 degrees which if your not doing anythign is fine but after 30 minutes of running with no wind to cool you off that's damn near oven heat...

as much as i would like to agree with you cause the numbers make sense, here's where i think there's room for argument: on the road your legs are doing 100% of the work to move or body forward. On the treadmill, right after your foot hits the ground, and you start moving your body forward (or just moving your foot backwards as is the case here) you could basically stop doing any work except keeping yourself standing and the treadmill would move your foot backwards for you. Then when it gets the back of your stride, the only work you HAVE to do is lifting the weight of your foot and moving it forward again. It seems like you can, essentially, get away with "running" on a treadmill by only ever moving the weight of your feet, whereas on the road you are obviously moving the entire weight of your body. maybe...

You need to take at least two physics courses and one course in remedial logic.

JimFiore wrote:

As a "science guy" I have always been interested in quantifying things. I HAVE compared HR monitor readings and other types of workouts on the track to the treadmill. As I stated, once the treadmill is calibrated and the wind resistance corrected for, I found the correlation to be spot-on.

You guys need to take a physics course. Science is good.

If I'm not mistaken, moleman also has a science background. Anyway, it seems as if you all agree that running on a level treadmill is easier than running on level ground. (I know this is true from my own heart rate readings.) Raising the incline of the TM can compensate for the lack of wind resistance making the TM comparable to running outside. Is that a fair assessment?

It's amusing to see how vehement people are on both sides of this issue. It all depends on how the speedometer is calibrated. I have been on some treadmills that were very slow, others that were very fast. In my experience, they can feel 10-15 seconds a mile off on either end. Funny how people, even smart people who understand physics, will construct elaborate, illogical theories to fit their experience, but never question whether the speed is accurate.

Question for Jim. Do I have this right?

I think of it as simply changing the frame of reference. Rather than measuring speed/work by fixing the earth and moving the runner, we are fixing the runner and moving the earth below him/her (of course it is not actually the earth, but the effect is simulated by the treadmill). In the first case the runner "moves" forward relative to the earth. In the second case the earth "moves" backward. Regardless, the same amount of work is required to move the same distance at the same speed.

Now some are bothered by the fact that the treadmill is actually moving. Intuitively, this must assist running in some way. But am I correct in thinking that if I ran on a treadmill that was not powered, but frictionless (as in, there is a belt but there is no resistance on it), that although I would stay in place, I would actually only be doing enough work to move the belt backward (which presumably is less work than one creates when running)? Ergo, I actually need the belt to be moving backward so that I must apply enough force to the belt to stay in one place, which is exactly the same as the amount of force I would have to apply to move forward, if I were outside.

dukerdog wrote:

Everything I've seen is a theoretical calculation based on reduced wind resistance. . . . Running is too complicated a process to believe much of anything based on theoretical calculations.

I think the most likely explanation of why that guy found running on a treadmill so much easier is that it was calibrated incorrectly.

The effect of wind resistance on energy expenditure at a given running speed, especially at higher speeds, is HUGE. Also, modern treadmills typically have very forgiving running surfaces, much like "tuned" indoor tracks.

I love treadmill running, think that it is a valuable form of training, and have run thousands of "miles" on lots of different machines. But I would be kidding myself to think that the impressive times that I have run on treadmills would translate into similarly impressive performances on terra firma.

Jack Daniels, where are you? Speak up!

Regardless of physics, i think TM running is easier. Just go to your local track, run a 6:00 mile, then later do one on a treadmill. The treadmill is easier. Boring as hell but slightly easier.

oldguy wrote:

Sam,

I'm surprised to hear this stuff from you. There is a lot of information out there on this topic. The bottom line is that running on a treadmill at 0% grade requires considerably less energy than running forward on flat grounds. The higher the speed, the bigger the difference.

It's true that your body temperature may get higher on the treadmill, in the absence of circulating air.

as i said, your milage may vary - ymmv. all i can say is that i use a wide variety of treadmills at the local ymca. i understand some, or all, my need calibrating. but in MY experience, i tend to run about 20 secs per mile FASTER outside.

i find it HARDER to run on a treadmill, in part b/c it is often hotter indoors and the lack of the cooling effect of a nice breaze makes things tougher. most of the routes i run outdoors are pretty flat, so that is not much of a variable for me, and if it was/is it would contribute to making runs outside harder and thus slower.

i accept that if the treadmill is not calibrated correctly and i am running farther on the treadmill than it says this would explain my thoughts. all i can say on that is that my experiences are consis over the use of many treadmills - both at the ymca and lots of hotels (i travel for work a bit).

i have no comments on the hrm issues as i do not use a hrm.

as an aside, most of the people i know that are critical of treamill running seem to come to it with no real experience running on one. many, not all, have an anti-treadmill atitude to begin with as if it is not "pure" running or that those that do it are not "real runners." as a result they seem to have a desire to conclude that it is "easier." that is MY experience, yours may be dif.

lastly, jim f's thoughts seem to line up with my experience.

my 2 pennies.

The treadmill was hard when I had first started using it. I think it was because I was not used to the consistant pace. I also think that it is usually hotter and the air is stagnant whenever I use a treadmill. So it took a while to get used to using one but I can now hammer out some runs on one. I always adjust the incline (uning charts from Daniels formula).

Just to offer myself up for some laughter...I fell off a treadmill when I had first started running on one and I was still getting accustomed to it. I was in the school rec center (college) in the aerobic area (treadmills, stairmasters, elypticals, so on) with all of the hot girls (picture Bally's commercial). I start cranking this treadmill to its limit. I even put the incline up quite a bit. So I am cranking out this hardcore pace on what has become a death machine and this beautiful girl in her sports bra and tights walks to my right.

So I think, who am I to deny her a look? (that is what she wants right?)

I look, and then go down. Hard. It hurt. It is hard to play it off too, like I meant to do it. So I just kind of walk it off. I still remember this chubby kid cranking out 15min/miles next to me laughing so hard he almost fell off of his treadmill too.

sam w wrote:

as an aside, most of the people i know that are critical of treamill running seem to come to it with no real experience running on one. many, not all, have an anti-treadmill atitude to begin with as if it is not "pure" running or that those that do it are not "real runners." as a result they seem to have a desire to conclude that it is "easier." that is MY experience, yours may be dif.

I agree with this point. Many of my most intense training sessions have been on treadmills. Although I find treadmill running at a 0% grade to be much easier than running outdoors at the same pace, I generally do my treadmill workouts at a much faster pace. Treadmill training, even at a 0% grade, can be brutal.

Hi Chris K

How are things at BC?

There is too much variance between machines to give a difinative answer. The various factors that the other writers have mentioned certainly apply (sweating due to lack of air movement, boredom etc.) but if you find a machine that's comfortable for you it can be a great workout.

But as the science guy that you are - I'm surprised you haven't gotten into the argument over whether it requires less force to run on a treadmill. It IS assisted running if you consider the requirements placed on each phase of the stride. The non-contact leg has the same basic stressors. But the contact foot is pulled along the ground. You are only using the musculature involved to keep your leg in the proper position. Anyone in tune with their body would find it easy to compare. Your relative stride is longer on the treadmill with less force applied.

northrunning wrote:

It IS assisted running if you consider the requirements placed on each phase of the stride. The non-contact leg has the same basic stressors. But the contact foot is pulled along the ground. You are only using the musculature involved to keep your leg in the proper position. Anyone in tune with their body would find it easy to compare. Your relative stride is longer on the treadmill with less force applied.

IF that were true, it should be a universal, or near universal experience for people to run FASTER on treadmills. while i know people who claim they do run faster on them, i also know a significant number of people who say they run slower on them.

all this being said, i have never seen any scientific stuies on this. if anyone has a link to one i would like to see it as i think it would be interesting.

the treadmill chart linked in an above post is one i have seen many times, but where did the DATA that it was based on come from? it cites no authority to support it.

my strong suspicion is that if the authors could be located you would find it is mostly based on their assumptions or only min data - much like the 220-age formula to get max hr.

there seems to be an overabundance of voodoo "science" in the realm of fitness/athletics.

There are many non-force factors that would keep someone from running faster on a treadmill. But if you can eliminate them you can run faster on the treadmill.

Calibrate any machine and I'll run a faster mile on it than I can on a track. The greatest impediment to speed for me is leg strength vs. body weight. The treadmill doesn't require the same amount of force from my contact foot so I can maintain an open stride much easier. I concur that it requires an inclination of the treadmill to force me to push off more powerfully to counteract the advantage I get of the surface moving away from me.

I want to be clear at the outset that I am talking about a properly calibrated TM that has been corrected for wind resistance (typ 1% incline at easy pace) and under otherwise identical conditions (temperature, humidity, etc.) All I'm talking about is the treadmill vs. the road.

I'm seeing a lot of talk about so-called "assisted running" here. A treadmill does not assist you. All that matters is your motion relative to the surface you are running on. That's the physics of it. Unless YOUR biomechanics change on the TM, there's no difference in energy expenditure. For example, for some reason (perhaps purely psychological) you might twist your upper body more or lengthen your stride while on the TM. That's a separate issue as it will vary with the individual. The studies I have seen comparing overground and TM running indicate that major changes in mechanics do not occur. I saw only one study that said there were some minor changes in the lower leg/foot actuation, but they were looking for possible injury sources.

A treadmill does not "pull your leg back for you". That would only be the case if you were somehow suspended above the unit (hanging onto the handrails perhaps). I think some of you are getting confused by the start-up effect given your momentum (or lack thereof). When the TM first starts, you can let it "pull your leg back" because you are most likely still holding onto the handrail or console. In contrast, try to PASSIVELY (no work on your part) let your leg be pulled back while the rest of you stays in place with your hands in the air. You can't do it (not without falling on your face anyway). You have to create a force to propel your mass WITH RESPECT TO THE SURFACE YOU ARE RUNNING OVER. It simply doesn't matter that you are not moving with respect to the floor or walls. Force=mass*acceleration. Everytime you stride forward, bringing your center of mass over your foot plant, you are accelerating your mass. It then decelerates as you coast through the air (no way to apply force mid-air). For the same average velocity and mass, the force will be the same unless you somehow reduce the acceleration. You can reduce peak acceleration by increasing stride rate, but you'll take more steps so the change isn't that great (and will be zero if your stride rates on the road are the same as on the TM). The stride rate will also affect the vertical component of force. You can't just decrease the vertical component without the side effect of increasing stride rate. That is, with a smaller vertical component you will land sooner, thus requiring an increase in stride rate to maintain the velocity.

It is very true that wind resistance is not linearly proportional to running velocity. The 1% incline correction for wind resistance is good for moderate speeds. I find that for faster work (say, a tempo run, or in general faster than 6 min/mile) 1.5% will be better. I would imagine that for very fast work (sub 5 pace) 2% may be better still. These numbers are based on my personal experience and my analysis of wind loads (see the chart in JTD's book on the effect of headwinds).

One factor that no one has mentioned so far is the tendency of treadmill tracks to have too much "give". I am slower on the treadmills on which I run, particularly at the higher speeds, and I think it may be for the same reason that I am slower when running on grass or dirt than I am on the road or a track -- the treadmill absorbs too much of the impact energy of my foot rather than bouncing it back in the air the way the road would.

They are the same theoretically. Any physicist will attest to that. But in practice there are things that make one easier or more difficult for some people: wind resistance, temperature, boredom (or lack of it for those who like to watch TV or listen to music while they run), and other factors. For me, treadmill running is harder because of the steady pace. When I run outside I continually vary my pace without even thinking about it, and I run better and easier because of it. For some, the steady pace of a treadmill might be easier. We are all different.

For those doubters who don't believe that you have to propel yourself forward on a treadmill, try standing sideways on the belt and jumping up and down. See which way you go.