In addition to all the great advice you've already received, I would also consider doing some interval work. I usually measure these runs by time, not by distance. You can sprint for 30 seconds, then walk for a minute (repeat for a total of 20 minutes) or run at a fast pace for a minute, then jog slower for 2 minutes (repeat for a total of 20 minutes). When I do this, my heart is usually pounding through my chest in no time. But doing this for one of my three weekly runs makes a difference for me (after a month or so).
You might also consider doing some more vigorious cross training on your off days. If you don't already do anything, start walking. Then after a month or so try biking, swimming, dancing, using an eliptical, etc. once a week in addition to your three runs.
It sounds like you've hit a running plateau. Now it's time to challenge your body to do more. Don't underestimate yourself. You CAN do it!!!
Edited by: BECKYBEFIT at: 9/27/2012 (10:54)
~Loving Life in the Mountains~
"Every great success is ultimately the triumph of persistence" -Ralph Waldo Emerson
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