45 Minutes

After a 5 minute warm-up, I began my intervals with 50 seconds of running and 90 seconds of walking. After about 20 minutes my left leg started to cramp so I walked for about 10 minutes until it loosened up and then went back to the intervals. Although 10 seconds doesn't sound like a lot, I think I might have pushed too hard. I read through Jeff Galloway's book this afternoon and he recommends that you stick with two weeks of the same intervals before increasing to the next level. With the Dallas Marathon coming in just a few days, I really don't want an injury.