Imagine, if you will, that you have a ten-year-old son, and he comes home from school one day and tells you he is starting on a new exercise program that will make his arms as strong and healthy as possible.
"Good," you say. "Tell me about it."
He tells you he is going to take a 5 pound dumbell and build himself up until he can do a thousand repetitions of a bicep curl with each arm.
If you are sane, you will discourage your son from doing this. It will never make him "strong," and it will likely damage some of the parts and pieces of his arms and elbows. (Ignoring the fact that kids shouldn't be lifting weights at that age) you tell him it would be better to build up his strength with higher weights, such that he can only do 3-5 repetitions before failure.
And what is "jogging" if not repeating the same minimally-exertive exercise (jogging one step) a million times? It doesn't make you any stronger or more "fit." All it does is make you more able to jog, which is pointless.
It does burn some calories, but the fact is, it inhibits muscle development in other areas of the body (while doing nothing for your legs either). Look at the first 100 finishers in any local 10K race, and about the best you can say for them is that they are all skinny. None of them has any upper body muscle development. This is not a coincidence. Distance running inhibits muscle growth.
Jogging is not even particularly good for your heart. You elevate your heart rate to the "aerobic range" and keep it there for thirty minutes. So what? Your heart adapts to where it can do that easily. So what? The only time jogging has any significant benefit is when you are "jogging" in an area where there are a lot of hills, and your heart is forced to elevate to the changing levels of exertion. Jogging on level terrain is borderline worthless. Better than having a Big Mac, but not much. It is the leg equivalent of doing a thousand bicep curls with 5 pound dumbells.
For a given investment of time, you would be much better off do to ten or fifteen minutes of interval training, then lift weights or do calisthenics for fifteen minutes, and finish with a good, full-body stretching routine. Run for fun, but no more often than once a week.
I personally do most of my interval training on a stationary bike, but it can also be done in the form of running/walking. It is best when the level of exertion progresses with each interval until the last one, which is a maximum effort (heart rate 220 minus age times .8). Six intervals is plenty, and can be done in 10-12 minutes, leaving you more exhausted than a half-hour run. I know from experience.
I was a runner for 35 years, and I still enjoy it, but as pure exercise it is horribly over-rated. It will inevitably injure your knees, hips, and/or your feet. For most of the time invested in health and fitness you should be doing something other than "jogging."
As AquaAthena pointed out, swimming is one of the best all over body work-outs there is. Second only to...
