Good Treadmill Intervals

Back on the treadmill today for 7x400m intervals. Last time I felt they were a bit soft at 12.5kph. Today I tried 12.8kph, and felt good and stuffed by the end. The intervals were separated by 200m at 8 kph.

Got the HR up to 171. It could go higher I suppose, but I felt like that was about where it should be. At least I donb't have to worry about intervals for another fortnight.