How does one prevent a decrease in muscle mass when running ( 6 miles
at 9 minutes a mile )?

I am a 6' 137 pound (25% body fat) 33 year old female who has been
running and weight training off and on for fourteen years ( more on
than off ). I am now, however, trying to concentrate more on building
mass ( 5-8 reps of a heavier weight ). I continue to run 6 miles a day
and am concerned about losing the muscle I am trying so hard to build
when I run. Specifically, I run 6 days a week and lift weights about
four hours a week.

I recently read in the book " The Edge",  by Ben and Joe Weider, that
those who want to build muscle should not do more than 30 minutes of
cardio a day or they are defeating the purpose. Apparantly, they say
more than thirty minutes and your muscles will start shrinking.

Since I love running my six miles so much, I am trying to find a way
to avoid this problem while continuing my routine.

Would a protien/carb drink in the middle of my run help? How about
glutamine in the middle of my run? What can I do to make sure I am not
losing my muscle?

By doing more cardio your muscles are changing, not shrinking.  I
would suggest reading the article "Muscle, Genes and Athletic
Performance" (Ref. 1, sorry, this is purchasable online, but I would
suggest finding it at your local library). The article in Ref. 2 is
free, but a little off topic.

You have three competing types of muscle in your body: slow type 1,
fast type 2a, and fast type 2x fibers. Each performs a different
function. Fast fibers do tasks like lifting weights and sprinting
(high power exercise). Guess what slow fibers do... continuous,
energy-consuming tasks... like running. The fibers -can- be changed
into one another, but... they have competing agendas. Namely, power
and endurance. Sprinting is an alternative to running that helps build
fast fibers, but your going to have a lot of trouble if you decide to
try running a marathon after sprint-training for a few months.

Protein/carb drinks are not going to help, that's what a balanced diet
is for.  If your looking for a lot more muscle mass, I would suggest
cutting your running routine to a fraction of what it is now and
increasing your weight training (you can still run, just not nearly as
much).  If you want just a little more mass, you really are not going
to have a problem... simply increase the weight and keep the reps down
(about 10 to 12 reps per set), and maybe decrease your running from
six miles to four. Do the weight training before running if you are
doing it all in one session.

Hope this helps,

krobert-ga


References:

1) Muscle, Genes and Athletic Performance; Scientific American,
September 2000; by Jesper L. Anderson, Peter Schjerling, Bengt Saltin;
 8 Page(s)
The cellular biology of muscle helps to explain why a particular
athlete wins and suggests what future athletes might do to better
their odds

2) Scientific American: Muscular Again
http://www.sciam.com/article.cfm?articleID=00023F2F-FC20-1C72-9B81809EC588EF21&pageNumber=1&catID=9