I am not what anybody would call a fast runner. I generally don't run faster than a 12 minute mile. When I am just out there to see the scenery and make the miles go by, I usually settle into a slower than 12 minute mile pace. For a long run, I usually average even slower.
But that doesn't mean I'm not capable of running faster than that. It's just not what I focus on. I've recently been trying out something called a Maximum Aerobic Threshold run. The idea for this is to get the body used to running with fat-as-fuel instead of using glycogen. The way to do this is to SLOW DOWN to a painfully-slow pace. The best way to approximate this slow pace is to breathe through your nose while running. When I do this, I usually slow down to an embarrassingly slow 15 minute mile.
The good news is that I can do this pace all day long, provided I have the patience for it. The bad news is that if I were to run any races at this pace, I'd be kicked off the course. The good news is that I don't run races at this pace, I train at this pace. Probably the hardest part about this is keeping the runner's ego away.
One of the benefits of this, is after a few weeks of running like this, you can get better endurance for the races. I decided to run 3 miles as fast as I could: Trying to break my 3 miles in 30 minutes barrier that I have never broken before.
I headed out with my new running shoes, the Merrell Barefoot, and ran as hard as I could for the whole 3 miles. Average pace 9:03, best pace 07:22 (for just a few moments). That was fun, but I won't do it that much more until after the marathon is over with.