On Wed, 28 Mar 2007 08:10:14 -0500, Marilyn Harris  
<[log in to unmask]> wrote:
>
>> don't just run for exercise because it tears down your muscles.
>
> I would say, if I said anything about this, that it wears down the  
> knees. As long as you are taking enough protein I would imagine that  
> your muscles should not be worn down, but kept at an optimum state...?

Maybe optimum for running.  The body adapts very specifically.  If you ask  
it to run long distances, it will adapt itself specifically to that task.   
One such adaptation is dropping unnecessary muscle mass.  Look at the legs  
of sprinters vs the legs of distance runners and you will see the  
difference.  Each is optimized to their specific activity.

When you relate this to weight loss, the more muscle you have, the more  
you increase your basal metabolism, which will increase the calories you  
burn.  In addition, this changes the body's energy systems.  Not only will  
the sprinter's legs be heavier and more muscular, but the muscles will  
expect to output maximum power for brief durations, using stored  
carbohydrates as the primary fuel.  They don't need fat, so the body  
doesn't need to store it.  The muscles of the distance runner will be  
using fats as fuel, so the body will store some fat to meet this need, and  
will be stubborn to give up its last reserves.

-- 
   Robert Kesterson
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