'invisible hill' intervals were as painful today as i imagined them before hand. i warmed up for 10 minutes and then started in on the first of three sets of 3 x 2 min on/2 min off intervals. the first and second sets were on the way out. the third set on the way back. i rested for six minutes between sets.
after the final set of 3 x 2 min on/2 min off intervals, i decided to do one set of 4 x 3 min on/1 min off. let's just say that wasn't my best idea of the day. my legs are toast! (20.05 miles @ 16.6mph)