Big workout today

Today, I decided to workout hard. I hit the treadmill for 60 minutes. I alternated between a 4.0 mph walk & 5.5 mph run. I used my IPod to alternate the pace. One song walk, one run. The best part was that I never knew how long each segment might be. I could run a 2 minute Ramones song and walk an 8 minute Metallica song or vice versa. It definitely was a good hard work out.