Is it true that it doesn't make any difference if you walk or run the same distance, because the used energy (burnt calories) are all the same??

So basicly running is just a timesaver?

Is it true that it doesn't make any difference if you walk or run the same distance, because the used energy (burnt calories) are all the same??

So basicly running is just a timesaver?

Calories expended are based on both intensity and duration of activity.

If the distance is the same, increase in intensity will mean decrease in duration.

But metabolism will be higher for a slightly longer time after running fast than after walking and some energy will also be expended in cooling down, so there is a slight advantage to running over walking.

Thanks for the answer. Here is a related question:

Is there such a thing for humans as optimal speed? Like for cars where the car runs in the best economic way? I assume something similar exists for humans. Here is the logic of it:

If you walk really slow, you are just putting your legs in front of one other, but you are not using the impulse. On the other hand if you are running very, very fast, the airresistance is growing exponentially with your speed's increase, thus you have to work more.

So between very fast running and very slow walking there should be an optimal speed where the body burns the minimal calories needed to cover the distance.... Correct?

wanna burn calories easy? swim...its the best thing there is.

The question is purely scientific...

My estimate for the ideal speed is 5 mph. Also it is possible that for different bodytypes it is slightly different.

But let's say you have to cover a pretty long distance (1000 miles or whatever) and you have water but you don't have food. If time is not important, what speed would you cover it with to conserve the most energy???

Thanks for the answer. Here is a related question:

Is there such a thing for humans as optimal speed? Like for cars where the car runs in the best economic way? I assume something similar exists for humans. Here is the logic of it:

If you walk really slow, you are just putting your legs in front of one other, but you are not using the impulse. On the other hand if you are running very, very fast, the airresistance is growing exponentially with your speed's increase, thus you have to work more.

So between very fast running and very slow walking there should be an optimal speed where the body burns the minimal calories needed to cover the distance.... Correct?

A car cannot be trained, a human can.

The limit on human performance is oxygen availability to tissues. This involves:

1. Taking in enough oxygen (lung capacity)
2. Transfer of oxygen to blood (alveolar surface ratio)
3. Transport of oxygen (Hemoglobin levels in blood)
4. Supply of oxygen to tissues (cardiac output)
5. Efficiency of utilisation of oxygen (fuel substrates, fuel stores, recovery, high anerobic threshold, lactate disposal). This basically means are you using glucose or fats (which depends on intensity and duration of exercise), do you have sufficient stores to maintain that duration and intensity, can you tolerate periods of oxygen deprivation to tissues (such as those which occur at very high intensity exercise), can you recover fast from build-up of lactate (which occurs during oxygen deprivation in muscles such as at high intensities and causes muscle fatigue and slows you down), can you easily dispose of the lacate (which depends on the quality of your muscle and the ratio of slow twitch and fast twitch fibers as well as availability and efficiency of utilising oxygen, which in turn is determined by metabolic machinery of the cells).

All these factors are improved by regular and constant exercise until they reach maximum efficiency.

Maxium efficiency is determined by the upper limit of changes possible through type of training, proper diet and genetic potential.

I'm not very familiar with the physics (resistance etc) but even things like altitude, turf (sand or grass), heat (salt loss, dehydration) cold (hypothermia) can affect performance.

A car cannot be trained, a human can.

The limit on human performance is oxygen availability to tissues. This involves:

1. Taking in enough oxygen (lung capacity)
2. Transfer of oxygen to blood (alveolar surface ratio)
3. Transport of oxygen (Hemoglobin levels in blood)
4. Supply of oxygen to tissues (cardiac output)
5. Efficiency of utilisation of oxygen (fuel substrates, fuel stores, recovery, high anerobic threshold, lactate disposal). This basically means are you using glucose or fats (which depends on intensity and duration of exercise), do you have sufficient stores to maintain that duration and intensity, can you tolerate periods of oxygen deprivation to tissues (such as those which occur at very high intensity exercise), can you recover fast from build-up of lactate (which occurs during oxygen deprivation in muscles such as at high intensities and causes muscle fatigue and slows you down), can you easily dispose of the lacate (which depends on the quality of your muscle and the ratio of slow twitch and fast twitch fibers as well as availability and efficiency of utilising oxygen, which in turn is determined by metabolic machinery of the cells).

All these factors are improved by regular and constant exercise until they reach maximum efficiency.

Maxium efficiency is determined by the upper limit of changes possible through type of training, proper diet and genetic potential.

ummm u like totally forgat about body mass, center of gravity, and length of legs... this decide what is most efficient speed.

wanna burn calories easy? swim...its the best thing there is.
Good for building endurance, not as weight bearing though since we are weightless in water. For building bone mass muscle strength, you still need some weight training or other weight bearing exercise.

Good for building endurance, not as weight bearing though since we are weightless in water. For building bone mass muscle strength, you still need some weight training or other weight bearing exercise.

ummm like look at the calories burned per hour for activities not limited to running, walking, biking, and swimming. mmm...u changed ur pic...the one before that was pritty.

ummm u like totally forgat about body mass, center of gravity, and length of legs... this decide what is most efficient speed.

Like I said I'm not into kinetic modeling and mechanics, I only do physiology.

ummm like look at the calories burned per hour for activities not limited to running, walking, biking, and swimming. mmm...u changed ur pic...the one before that was pritty.

Ya I'm cool now.
(supposed to be animated but not working)

Ya I'm cool now.
(supposed to be animated but not working)

cause u had that sad look on the pic.

I really enjoy the conversation, unfortunatelly let's get back to topic.

I am not interested in how to lose weight. I am also not interested in a bunch of people with different bodytypes (at this moment).

What I am interested in is one person's most economic SPEED to move from point A to point B, using his own muscle, by stepping forward. You know guys, one step at a time.

I don't see why human's shouldn't have an ideal speed (as energy conservation goes) just like cars. I think I already presented the problems of too slow or to fast speeds.
So if you guys don't know, well just say, we don't know. No shame in that...

I would guess that race-walkers are close to the most efficient. They look goofy but I would suppose it is near maximum efficiency. Maybe the ultimate is if you do the race-walk technique but cheat. IIRC cheating means having more than one foot off the ground at the same time. I'm guessing here . . .

I really enjoy the conversation, unfortunatelly let's get back to topic.

I am not interested in how to lose weight. I am also not interested in a bunch of people with different bodytypes (at this moment).

What I am interested in is one person's most economic SPEED to move from point A to point B, using his own muscle, by stepping forward. You know guys, one step at a time.

I don't see why human's shouldn't have an ideal speed (as energy conservation goes) just like cars. I think I already presented the problems of too slow or to fast speeds.
So if you guys don't know, well just say, we don't know. No shame in that...

too many variables to consider. you want get exact answer. Like the most efficient speed for human is: 5.5920 km/s...
thats not going to happen because humans are all different...you might however figure out the constant associated with the leg length...muscle power...according to age of the human. A small boy age 3 most efficient speed might be 3.5 km/s, some old chap age 92 most efficient speed might be 1.5 km/s.

HERE it goes: I, the guy, don't know the most efficient speed for a human.

And what if that human ate lots of food before the walk?...center of gravity changes...pattern for more efficient walk also changes.

You want to know what is the most efficient walk speed for humans? calculate average speed humans do...humans are lazy...lazy means they want to conserve energy...which means speed of walk most efficient.

Anyways according to this article trotting is the most efficient technique of movement for humans...a picture of naked Greek athletes from Athena comes to mind hopping/trotting alongside the mideterranean coast. And speed relates to stride technique.
http://www.sciencemag.org/cgi/content/summary/308/5725/1096

HERE IS THE GOLDEN NUMBER: 3.6
3.6 km/h is the most efficient walking speed for humans since it is the average speed for humans.

http://www.thinkmetric.org.uk/speed.html

some old chap age 92 most efficient speed might be 1.5 km/s.


That is one bullettfast elderly... :)

I agree with you and I know the limitation of my question, nevertheless it is an interesting one...

Hrm. Hasn't anyone considered the total number of calories burned?

I might have to do that.

Okay, here's a graph showing calories burned per mile at certain walking and running speeds. The highest walking speed shown is 4 mph, and the lowest running speed is 5 mph. This info is for a person of average weight and was calculated from a chart found on a website listing calorie useage for various types of exercise.

http://home.earthlink.net/~parvey/sitebuildercontent/sitebuilderpictures/calories.gif

Note that the calorie useage jumps up when you go from walklng at 4 mph to running at 5 mph. Also, during walking, calorie usage goes down with speed. At running, it seems that calorie usage peeks at around 8 mph, but it is unclear as to how much of this is just due to statistical error, especially considering the dip at 7 mph.

Thanks for the graph. My estimate of 5 mph was pretty good if 4 mph is the lowest calories usage.
Somebody mentioned race-walkers, but I disagree, because too much energy is used up to hold themselves back from actual running.
I tend to think (although I could be wrong) that it is rather automatic, the most comfortable speed for the individual is the less energyuser...

An explanation why running is burning more calories than walking could be that at running the body is in air for a small amount of time and the extra energy is used to lift the body up instead of moving forward...

Here's a more detailed graph with some intermediate speeds added, and for three different weights for walker/runners.

http://home.earthlink.net/~parvey/sitebuildercontent/sitebuilderpictures/calorie2.gif

Running entails more isometric muscle contractions than walking--for balance etc.--and isometric contractions waste energy in terms of doing work. Also the coefficient of restitution of the best running shoes is nowhere near 1.0 so you waste energy every time you hit the ground unless you have developed a perfect zero-impact gait--which will probably require a lot of isometric contractions. So clearly you'll go farther without food by walking than by running.

If all else exactly balances out and it takes exactly the same number of calories to cover a distance at a 4mph walk as a 1.5mph walk, then the deciding factor will be the baseline calories burned by a body at rest. I don't have the tables but it's something like a couple of dozen calories per hour.

I doubt that a person with no excess body fat could walk for more than four days without food, and he would have to sleep. The calories burned by basal metabolism in that period of time would only be a couple of thousand and would have a minimal effect on survival duration.

It would seem that if you were planning on making this hike, the most important factor would be to gain as much weight as possible before starting out. Every pound of body fat is another 3,500 calories you can expend and that many more miles you can cover, minus a trivial amount for the metabolic baseline. Having ten pounds of fat to burn would outweigh (n.p.i.) the effect of any difference in walking speed.

If all else exactly balances out and it takes exactly the same number of calories to cover a distance at a 4mph walk as a 1.5mph walk,

Well, the posted graphs seem to contradict you. And it can be seen that at very low speed, it takes way more calories just standing and gaining/maintaining impulse and speed. Remember it is much easier to keep a mass moving than getting it to move...
So I tend to agree with the 4 mph most economic speed...