Day 3: Recovery, Thursday, August 29, 2013 Active rest day. Do 60 mins of steady state aerobic activity between 70% of max heart rate (MHR). Rowing machine, cycling, jogging, and swimming are all good choices. For some people brisk hiking may be enough to get heart rate to 70%.
Active rest is superior to resting completely for recovery. If you completed any of the strength workouts from Day 2 you are definitely in need of a rest day and recovery strategies that will have you ready for the sprint workout on Friday.
General formula for MHR is MHR = 220 - Age
Day 4: Sprints, Friday, August 30, 2013
Pick one of the three sprint workouts from this blog on sprinting. Warm-up extensively before sprinting at high intensity.