I read an something in a recent Runner's World that gave a chart of how long your long runs should be. It says that for 5k training, which is what I am doing, you should run between 12-15 miles or 1 hour 15 minutes-1 hour 45 minutes.
Last week, I got 6.75 miles logged and I knew I had to make an improvement. I went out Sunday with the temperature hovering around 90 degrees and very humid. It was overcast, though. This may sound weird, but it felt like a cool 90 degrees, so I thought I could definitely do more mileage today.
I had a route planned in my head. When I got to the southern most point of my route, the sun came out and that 90 turned into something else. I started feeling the heat in my chest and my head and that really makes it hard to push yourself.
I cut my route a little short, so I could get to a park with a water fountain. I stopped and rested for a few minutes to cool my core down a little. In the process, I ended up cooling my muscles too much. When I started back up to run the last 2 miles, my left calf was tight and stretching didn't help. I had to change my form, because it felt like if I kept running the way I normally do, I would pull my calf muscle.
I limped my way home and finished with 6.15 miles in 57 minutes. Still over 9 minute average pace. I did the 10 percent rule, except I ran 10 percent less than last time. Better luck next run.