Treadmills vs real walking

[dmpi]

I think this would be true if we had wheels instead of legs, but I'm not so sure the forces involved in our gait are as simple.

A car simply needs to overcome rolling resistance, which would be more or less the same on a treadmill or road (with similar surface).

But people are essentially pushing off, jumping, and landing. On a treadmill, the machine helps with part of the push-off motion since the treadmill moves your landed leg back for you.

I’m going to have to disagree with you here. This is a frame of reference problem.
Work can be measured by the relative motion between you and the ground.
It makes no difference if you are moving over the ground or the ground is moving underneath you feet.
To show you that are true, let me suggest a “thought experiment”. Suppose you slowed down the earth’s rotation to 7 mph. would it be easier 7 mph to run west (against earth’s rotation) or east (with earth’s rotation)? And how is running west any different than running on a treadmill with a belt 12,500 miles wide (with lots of stuff on it)?
Now going back to what you said about “the treadmill moving your landed leg back to you”. On a treadmill relative to the belt, when your foot hits the belt you need to expend energy and push back with your legs or you will fall on your face. This is because your body is not moving relative to the belt. A similar example of this would be jumping out of a moving car. Be prepared to expend a lot of energy when you feet hit the ground just to stay upright.

 

[Rich_by_the_Bay]

I think DMPI is correct about this. The difference is how much "distance" you might cover for a given interval, not the work expended.

Example: imagine a moving sidewalk like you see at airports. Once you step on and keep walking, minute by minute you are burning the same calories as if you were on the stationary ground. Of course you cover more distance (going faster relative to someone walking on the floor next to you) for the same amount of time (your walking distance plus the moving sidewalk's distance), but for a given time period you are burning as many calories as someone off the walkway.

Calories per time would be the same since your speed and work are relative to the moving walkway beneath you. Distance covered per time (speed) is different relative to the earth. Only difference with the treadmill is that the "moving walkway" is going backwards, resulting in no net distance covered (your walking distance plus the "negative" treadmill distance, effectively cancelling each other out - unless you are doing the 3 stooges thing).

Aside from that, though, the irregularities, changes in slope, wind, and other factors mentioned do make the treadmill a very different experience from a good real-world jog.

 

[Tiger]

I found the treadmill to be boring. Fortunately I only live a few blocks from a high school track. Besides all of the other benefits listed about I also enjoy checking out the many young women that use the track daily (that can get the heart up to a good steady beat).

 

[RunningBum]

Went for a long walk outside today and concentrated on how it was different. The main thing, besides what everyone has pointed out, is that my arms are swinging whereas on the treadmill I'm holding on to the bars on the side. That makes a big difference because it gets other muscle groups into the action.

Swinging the arms also gets your heart rate up too, which is good--up to a point, of course.

For those of you using a treadmill for good reasons, like joint issues, protection from UV rays, personal safety, need to stay home with a kid, etc, I commend you for continuing to exercise.

 

[haha]

I found the treadmill to be boring. Fortunately I only live a few blocks from a high school track. Besides all of the other benefits listed about I also enjoy checking out the many young women that use the track daily (that can get the heart up to a good steady beat).

True; but bloodflow to your legs might be compromised.

Ha

 

[twaddle]

I’m going to have to disagree with you here. This is a frame of reference problem.
Work can be measured by the relative motion between you and the ground.
It makes no difference if you are moving over the ground or the ground is moving underneath you feet.

Yes, work = force X distance. But the work we're interested in is the work of jumping, not just forward motion. Imagine a treadmill designed to move the tread back and forth. No net forward motion within the frame of reference, but you'd still get a good workout.

So, my only question is whether the machine is helping us do some of the work. The motor obviously supplies a source of external force. Your premise is that all of that force is applied to moving the tread, and my guess is that some of it is applied to moving our limbs.

Another way to look at this: which is the better workout, running on a treadmill or running in place?

 

[EngineeringMyFinances]

I prefer to walk outdoors, but when the weather's bad I use my treadmill.

My treadmill workout is a walk for 1 mile at 3 mph with the treadmill at maximum slope. Easy on the joints, but still gets the heart rate up.

 

[haha]

Treadmill slope compared to hills

I prefer to walk outdoors, but when the weather's bad I use my treadmill.

My treadmill workout is a walk for 1 mile at 3 mph with the treadmill at maximum slope. Easy on the joints, but still gets the heart rate up.

How does a treadmills maximum slope compare to a steep street in a hilly city?

 

[haha]

Beach running

When I lived at the beach I ran on the sand- partly the soft sand above the surf line, partly the packed stuff especially if it was hot. Seemed like great workout, and I never got injured. But I was young so that might not mean much.

Is sand both a good workout and relatively easy on the joints?

Ha

 

[CuppaJoe]

I would prefer the treadmill as I talked my way into cardiology due to a measurable steep decline in treadmill ability (LAD artery was 90% blocked). They don't call it "cardio" for nothing! My knees no longer allow treadmill so I walk as much as possible. For me, (before the blockage) treadmill felt like more a workout. My former gym shows movies and the gym before that had music and a view of a zen garden.

 

[W2R]

I thought of this thread during today's workout at the gym.

Even on a smooth, rubbery indoor track, some muscles are always working to keep us balanced as we walk. On the treadmill, just the act of putting my fingertips lightly on the rails seemed to balance me with no effort.

While I was walking, it occurred to me that it really doesn't matter which is better. Either the treadmill or walking on the track (or walking outdoors!) has beneficial effects. Just do it!

 

[EngineeringMyFinances]

haha:

How does a treadmill's maximum slope compare to a steep street in a hilly city?

My treadmill has a maximum value of "12.0" which I suspect is the percentage of slope rather than the angle in degrees. If percentage, that would be equivalent to an increase in altitude of around 600 feet for a 1 mile walk.

Perhaps you have paths in your neighborhood that have an equivalent sustained slope, but I do not. The advantage I see is that I can elevate my heart rate for 20 minutes (per recommendations I've read) without running and impacting my joints.

 

[haha]

haha: My treadmill has a maximum value of "12.0" which I suspect is the percentage of slope rather than the angle in degrees. If percentage, that would be equivalent to an increase in altitude of around 600 feet for a 1 mile walk.

So that is a little steeper than an inch in a foot. That is like a very low slope roof. There are side streets in my neighborhood that are so steep I won't try to drive up them, even in dry weather, so I think they are steeper than that. Though you couldn't do it for 20 minutes without having to find another hill, or go down and come back up. I can't just stride up, I have to actually lift my knee and lean into the hill pretty hard.

Thanks EngMyFin for the info!

Ha

 

[dmpi]

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Yes, work = force X distance. But the work we're interested in is the work of jumping, not just forward motion. Imagine a treadmill designed to move the tread back and forth. No net forward motion within the frame of reference, but you'd still get a good workout.

So, my only question is whether the machine is helping us do some of the work. The motor obviously supplies a source of external force. Your premise is that all of that force is applied to moving the tread, and my guess is that some of it is applied to moving our limbs.

Another way to look at this: which is the better workout, running on a treadmill or running in place?

If you take pictures of world class runners you will be hard pressed to get a shot with a foot on the ground. This is because running is mostly flying thru the air. Now when the air-borne runner’s foot hits the ground, does his foot get a “free ride” backwards? The answer is yes, but he better add some energy in if he wants to maintain the same speed.
The treadmill works the same way. When your foot hits the belt, it gets a “free ride” back, but you need to add some energy if you want to maintain the same speed.

The motor on the treadmill provides energy so you can exist in a frame of reference that is moving backwards. An analogy would be a car. You need to continuingly provide gas so you can exist in a frame of reference that goes forward 30 mph. By the way, In a frictionless world you would only need to provide energy to accelerate, once your at your desired speed, you could coast for free.

 

[twaddle]

Yes, I conceded the case for wheels earlier in the thread. You may be right in the running case as well, but I know when I run on a treadmill that not only are there qualitative differences vs running on a track, but I can feel the interaction with the motor. Sometimes I drive the motor, sometimes it drives me, sometimes we're in sync. In the end, it feels like less effort than running on a track. At least to me.

Edit: here's a random paper on the subject:

Treadmill training


When an athlete runs on the track, on roads or on firm ground, their legs create propulsive forces which accelerate their centre of mass and drive it forward. The athlete's centre of mass is decelerated during each recovery (early-stance) phase of the gait cycle, only to be accelerated forwards again as propulsive forces are created by the stance leg. As they continue to run, centre of mass is accelerated and decelerated over and over again as it moves steadily forwards.

When the same athlete runs on a treadmill, centre of mass is static (at least in the forwards-backwards plane). There is no forward progress; instead, the running surface 'disappears' behind the athlete. In fact, the treadmill belt moves the athlete's legs and feet under and behind her centre of mass and, to preserve stability, their key task is to move the support leg back in front of the centre of mass in time for the impact with the treadmill belt. The key function of the leg muscles during treadmill running is not to produce propulsive forces but to re-position the legs so as to keep the centre of mass stable.

 

[EngineeringMyFinances]

Depends

I took a look at the article twaddle references.

My takeaway: if you're a competitive runner, then stay away from the treadmill and use a real track instead. OTOH, if you're just trying to keep your fitness up, 20 minutes watching a sitcom while on a treadmill is better than 20 minutes watching the same sitcom while sitting on the couch eating a bag of chips.

 

[mb]

Physics wise there is no energy usage difference between you running at a constant speed on the treadmill and you running the same speed on the ground. Where the difference is when you accelerate. It takes more energy to accelerate on the ground than on the treadmill because on the treadmill you’re not really accelerating, rather the belt is and the treadmill is doing the work. On the treadmill it only takes seconds to accelerate to the speed your going to run at so this is largely a non-issue.

As other’s have mentioned wind resistance pays a slight role. However a fan blowing against you can most compensate for this, with the added benefit of cooling you off.
Another difference is the treadmill surface is springy and it’s almost impossible to find a similar surface outside. A rubberized high school track is close. While running on hard surfaces the energy is absorbed by the ground and you have to work harder to lift your legs. On a treadmill the energy of the foot strike is given back to you and your leg just bounces up.

Every article that I have ever read and I have read quite a few contradicts you. From: www.posetech.com/training/archives;00188.html

The scientific data and experience known to us say that treadmill running is easier then overground running. "It has generally been found that overground running does incur greater metabolic costs compared to treadmill running, particularly at faster speeds of running. At the present time the extent that other differences in running mechanics between overground and treadmill running affect oxygen uptake is not known" (Biomechanics of Distance Running, 1990, Editor P.Cavanagh, Human Kinetics, p.276).

My personal experience also suggests that treadmill running is easier. A favorite workout is mile repeats at a 5:30-6:00/mile pace with a 1/4 mile rest jog in between. I find it much easier on a treadmill than on the track. (See above about about effect at faster speeds) Although I cannot rule out pacing, psychological effects, etc. as confounding variables I am convinced that there is a difference. Also I don't think that the acceleration and deaccelerations are the cause.

I think that my "real" experiment plus the experience of many others trumps your thought experiment

MB