Hill running

Today I decided to do a bit of "hill" running on the treadmill. I worked intervals like this:

Minute 1: Walk 4 mph at a 2 degree incline
Minute 2: Run 7 mph at a 2 degree incline
Minute 3: Walk 4 mph at a 3 degree incline
Minute 4: Run 7 mph at a 3 degree incline
Minute 5: Walk 4 mph at a 4 degree incline
Minute 6: Run 7 mph at a 4 degree incline
Minute 7: Walk 4 mph at a 5 degree incline
Minute 8: Run 7 mph at a 5 degree incline
Minute 9: Walk 4 mph at a 6 degree incline
Minute 10: Run 7 mph at a 6 degree incline
Minute 11: Walk 4 mph at a 7 degree incline
Minute 12: Run 7 mph at a 7 degree incline
Minute 13: Walk 4 mph at a 8 degree incline
Minute 14: Run 7 mph at a 8 degree incline
Minute 15: Walk 4 mph at a 9 degree incline
Minute 16: Run 7 mph at a 9 degree incline
Minute 17: Walk 4 mph at a 10 degree incline
Minute 18: Run 7 mph at a 10 degree incline
Minute 19: Walk 4 mph at a 2 degree incline
Minute 20: Run 11 mph at a 2 degree incline
Minute 21: Walk 4 mph at a 2 degree incline
Minute 22: Run 11.5 mph at a 2 degree incline

I liked this workout. It reminds me of some progressive Crossfit workouts. My legs actually feel good after running the hills.