Primal Blueprint Fitness Sprint Workout Three

I missed my Primal Blueprint Fitness sprint workout last week. Today at lunch time I walked up the  from my office to a small, mostly level field. It was about a half mile walk in 14 minutes ( office -> car -> office -> change -> up hill ).

Then I ran a couple series of intervals. The first series was six sets of running for 30 seconds at 50% speed alternated with 60 seconds of walking. This was followed up with six sets of running for 15 seconds at 75-90% speed alternated with 90 seconds walking. Then I walked back down the hill to my office 0.3 miles in 9 minutes.

This was a nice work out. I ran hard. I felt good afterwards, minimal knee pain. I still feel energized nearly three hours later. I hope it lasts throughout what seems like it's going to be a long, boring meeting.