Sprint intervals:

(adjust speed to individual ability) – This is me (average recreational runner ;-))

1 min run ( flat surface) speed 5.5 mph

30 second sprint speed 7.5 to 8.0 mph ( 1 minute rest between sprints) * 5 sets  ( flat surface)

2 min run 6.5 after last sprint rest interval ( flat surface)

30 second sprint 8.0 ( 45 seconds rest between sets ) * 5 sets ( incline of  7 degrees)

2 min run run ( flat surface) speed 6.5 mph after last sprint rest interval

1 min walk ( flat surface) 3.5 to 3.7 mph