Notes
warm up about 0.4 miles, then 1 minute intervals:
6 mph -- 8.5 mph,
6 mph -- 9.0 mph,
6 mph -- 9.1 mph,
6 mph -- 9.2 mph,
6 mph -- 9.3 mph,
6 mph -- 9.4 mph,
6 mph -- 9.5 mph,
6 mph -- 9.6 mph,
6 mph -- 9.7 mph,
6 mph -- 9.8 mph,
6 mph -- 9.9 mph,
6 mph -- 10.0 mph,
then 6 mph for about 0.5 miles to round out 4 miles total.