Calories burned, running vs walking

Typically the stance is that calories burned is a direct result of distance traveled. This is sort of true, but not really. For example, if you walk 10 miles, then you are walking a very straight line (one foot always on the ground) toward that 10 mile marker. When you run, you are actually jumping off the ground with every step and therefore you actually travel a little bit further when you run 10 miles than if you walk it. Since you traveled a little bit further, you burned more calories. Also, as you mentioned, running increases metabolism, and also, the body needs to repair more after running 10 miles then after walking it, so you are burning more calories there.

Not to mention that when you run, you hold your arms so that the point from the elbow to the hand is pretty much parallel to the ground. Casual walkers don't do that, and so are expending less energy just because of that. In order for a walker to compare even at all with a runner, they have to swing their arms while they walk the whole way, and keep a pace that is strong enough to make them sweat. Most people who defend walking don't do that. Go to any park and look at what you see - thinner runners and fatter walkers. Let's also not forget that you might be able to run 10 miles in about an hour, but it might take you 2 1/2 hour to walk it. At some point, running wins by time allotted alone.

Running wins. If that is your stance, then you win too.

It's basic physics. You're translating a mass a certain horizontal distance. Within the relative efficiencies of movement, it doesn't matter how long it takes. If you complete it faster your power output is higher but the total energy expenditure is the same. Now, the relative efficiency may be different depending on the means of locomotion. Generally running requires a higher energy expenditure than walking because you must propel yourself off of the ground, but there isn't a lot of difference between paces until you get to the extremes (mechanical efficiencies change).

As a general rule, a 140 lb. person burns about 100 calories per mile for running and about 85 calories per mile when walking. Heavier people burn a little more because they're translating a higher mass. That runner will burn 100 calories over the mile whether it takes 7 minutes or 10 minutes (there will be a very modest change for very fast and slow paces as well as some individual variation).

The calories burned due to a reved-up metabolism after the fact are a second order effect. So, running is a much more time efficient at burning calories than walking because 1) it burns more calories per mile, and 2) it takes less time to cover a given distance.

Even if you accept the fact that the difference in distance between running and walking (i.e. jumping off of the ground) is negligible, there's still the fact that after you're done running you are still burning calories going about the rest of your day. Let's say you walk 10 miles in 1:40. Instead you could run it in 1:10 and have another half hour to walk around and do your daily activities which also burn calories. Therefore, I'd have to go with the running.

You're wrong. When you account for the small bit that you leap off the ground over 10 miles, it accounts for a signfificant amount. Studies have taken that very fact into account. Obviously the effect is less if you walk/run only 3 miles, but it is significant when 10 miles is covered.

Walking 10 in 1:40 is a pretty fast clip! I have been at 5 mile races where people RUN them in 50 minutes...

I'm wrong? Did you read my message? In effect I stated that running requires a 15% increase in energy expenditure to cover a given distance. I think 15% is significant. If you think it's way more than 15% I'm afraid that you're mistaken. I've seen these (and similar) values in numerous publications. Running are walking are not equal, but running doesn't require twice the expenditure of walking either.

Also, the effect of doing your workout faster (say 1:00 vs. 1:10) is very small (an extra 10 minutes at basal rate). I'm not going to quibble about an extra 10 calories here or there when the average distance runner is sucking down in excess of 3000 calories per day, and a pound of fat is roughly equivalent to 3500 calories.