Treadmill or real running: which burns more calories?

May 9, 2004 3:38 AM

PhysicsFilter : which burns more calories, a treadmill or a road run? [MI]

Despite being a fat b*****d, I go down the gym and do a bit of running on the treadmill. Nothing too stressful, but it burns off a few calories. If I try this on the road, I'm knackered within seconds. What's happening?

Part of me wonders if treadmills are less effort. If you put one on the flat, then you're using energy to bounce your body mass up and down and to flail your legs around, but are you actually using any energy to propell yourself forwards? Is it this extra effort that's knackering me when I try it on the road?

I'd suggest it's that the treadmill is flat and the roads aren't, but I live on the Fens - we give pancakes a run for their money...

NB: I tend to 'run' at about 12kph / 7.5mph and I weigh about 134kg / 295lbs, if that accentuates the problem. I'm not a small bloke...

posted by twine42 to Health & Fitness (19 answers total)

Normally, treadmills are "easier". There are new machines that vary the incline to mimic going up a hill, but I've yet to see one copy the downhill run, which tends to exercise the back parts of the foot and leg. Also, a treadmill has a consistant surface that is less shock-absorbing than say, grass or sand. That means you get more bounce-back, which makes things easier as well.
posted by Civil_Disobedient at 4:05 AM on May 9, 2004

Oh man is this ever true. I run on the treadmill at least 45 minutes, 3 times a week, but as soon as I start pounding the pavement, I'm out in like 15 minutes. I'd like to start running outside more, but I guess I have to build up my ability again.
posted by corpse at 8:35 AM on May 9, 2004

You're also probably running faster outdoors. I tend to do much quicker times when the treadmill isn't setting pace for me. I blame poor perspective and other people's eyes on me,

Outdoor runs are harder and more fun, but if you're heavy, your knees will thank you for sticking to a treadmill. Plus, that monotony ensures that you'll get a consistent workout.
posted by Mayor Curley at 8:36 AM on May 9, 2004

meant to add-- if you set landmarks to keep a pace like what you do on the treadmill, you'll find that the difference is pretty negligible except for leg soreness. So I think that aside from pace (and wind, especially on the Fens), the difference is pretty small.

Map your route to the half-mile and time yourself on a still day, keeping your gym pace. You'll probably find that it's easier than on a treadmill because you're not so incredibly bored.
posted by Mayor Curley at 8:40 AM on May 9, 2004

i've never run on a treadmill in my life, but physics-wise it should be identical (assuming it's motorised and flat) to running on the flat outside with a following wind that's equal to your running speed (so you're effectively running in still air in both cases).
my money is on mayor curley's idea - that you run faster out of doors. when i peer through the windows at people running on treadmills they always seem to be plodding along very slowly.
if it's important, use a heart monitor and run at the same heart rate.
posted by andrew cooke at 8:47 AM on May 9, 2004

I've seen a rule of thumb that a treadmill is about 2/3 of the effort of a road run, at the same speed and distance. (No source for it at the moment, so take with a grain or two of salt.)
posted by Zonker at 8:49 AM on May 9, 2004

A treadmill has some dampening that the road does not. You're getting back more G's from the road - it's harder on your body.
posted by filmgeek at 9:11 AM on May 9, 2004

You can also cheat a bit on a treadmill, say if it's on an incline, by just letting your weight push the belt down instead of expending the same effort you would be actually climbing the hill.
posted by Space Coyote at 9:19 AM on May 9, 2004

harder on your body doesn't make you more exhausted. when the tide's out i run on wet sand, which offers decent shock absorption without being so soft it screws up your form. when the tide's in i run on the beach road - concrete/asphalt much of the way. there's little difference in apparent effort - i don't notice any, and i'm sure a 1/3 extra (zonker's number) or a factor of 3 (corpse's numbers) would be obvious, especially at the moment, because i'm increasing distance and pretty much at my physical limit, either way.
posted by andrew cooke at 9:45 AM on May 9, 2004

The treadmill is slightly different, slightly easier. On the treadmill, your foot hits the tread and pushes off, but it also "slides" backward effortlessly on the tread as the tread moves back around. On the pavement (grass, track, whatever) your legs are purely propelling you forward.

I read something that confirmed this once, but Google isn't finding it for me. But it seems to make perfect sense, if you think it through.
posted by Shane at 10:41 AM on May 9, 2004

no it doesn't. it's physical nonsense.

imagine having a movie camera runing alongside someone who's running on the ground. if you look at the film it's like he's stood still and the ground is zipping by under him, just like a treadmill. they are equivalent (in that sense; see other comments here for differences in hardness, wind, psychology etc).
posted by andrew cooke at 10:53 AM on May 9, 2004

Google for the following terms: kinematics overground treadmill equivalence.
posted by Gyan at 11:22 AM on May 9, 2004

You don't need physics necessarily. If you "can't run on the road" but "can run on a treadmill" then the treadmill will burn more calories because you'll actually do it. I don't run much (once a year I get an urge to run, then I run 5 or 7 miles a few times then I realize "Oh yeah, I hate running!") but a treadmill seems about equivalent to me in terms of effort. Depending on the road surface my body takes much more of a pounding out of doors. My favourite surface to run on is trails with a nice carpet of pine needles (if you can have a favourite place to run if you don't like running that is).
posted by substrate at 11:24 AM on May 9, 2004

The newsgroup rec.running should also help. Check the threads in these search results.

Oh, and also try another search substituting biomechanics for kinematics.
posted by Gyan at 11:29 AM on May 9, 2004

maybe treadmill speed calibration is optimistic? makes users feel good...
posted by andrew cooke at 11:45 AM on May 9, 2004

Try to think of it in terms of the amount of work you are accomplishing. An outdoor run transfers a mass from one place to another. Running in place move it up and down, and flutters the legs back and forth. I'd suggest shorter outdoor runs. Fewer impacts on your knees and ankles, same amount of workout.
posted by scarabic at 6:23 PM on May 9, 2004

I'm training for a 10K in a few weeks and multiple people (runner friends and two personal trainers) have told me that running on a treadmill is equivalent to running downhill in the real world. I was advised to always bump up the incline on the treadmill a notch or else it's too easy. Seems to work for me. (Raising it up was like experiencing gravity for the first time.)

I've also been told that running outside works extra muscles - the ones for balance and changing direction and not-tripping and stuff - that you don't necessarily use a lot on the treadmill. I suppose that's true; on the treadmill I can just pound away but outdoors I'm constantly having to deal with uneven pavement, tree roots, other pedestrians, etc.
posted by web-goddess at 6:34 PM on May 9, 2004

As a high school cross country runner who is pretty damn good about pacing myself, I'de also have to say that a treadmill is less "effort." I know I run about 8 minunte miles outside. If I haven't run in a while and I do an 8 min/mile pace on a treadmill, I feel like I can fun forever on the treadmill whereas I can only go about 4 miles the first time around outside. To me, the difference is outside, I have to propell my self forward whereas the treadmill bring me back to the starting self lessening self-actuated propulsion.
posted by jmd82 at 7:20 PM on May 9, 2004

two people in a (slowly moving) train (both facing forwards)....

one, for no good reason, is running on a treadmill. by some strange chance the treadmill is set to the same speed as the train. the surface of the treadmill that he's running on is moving backwards at the same speed as the trees that go past the train windows.

another, curiously, has fallen through a hole in the floor, but, by running at the same speed as the train, along the tracks, has escaped death. the surface that he is running on goes past at the same speed as the trees that go past the train windows.

[walks away, sobbing, in frustration]
posted by andrew cooke at 8:19 AM on May 10, 2004