Treadmill vs land running

Cranking the treadmill up to a 1% grade is equal in the effort of a land run. So says this bit of research, A 1% TREADMILL GRADE MOST ACCURATELY REFLECTS THE ENERGETIC COST OF OUTDOOR RUNNING, J Sports Sci Date Of Publication: 1996 Aug. The study demonstrated equality of the energetic cost of treadmill and outdoor running with the use of a 1% treadmill grade over a duration of approximately 5 min and at velocities between about 9:00 and 5:20 per mile pace. You can't substitute substantiatial treadmill workouts for the road -- but in the plus 80/90 heat and humidity, it works for me. I recover faster and can run harder longer. Crank her up...