OK folks, so unfortunately I waited too long to do my tempo run outside and I'm terrified of the heat. The problem is that my treadmill only goes up to 9 MPH (6:40 pace, correct?). The treadmill also has an incline feature which allows you to increase the incline up to 15%. If I were shooting to do a tempo run, what % incline should I use at the maximum speed to approximate 6:20, 6:10, 6:00, and 5:50 pace? Thanks in advance for all the help!
You should do it by feel. Your effort is what counts, and there's no telling how the settings will compare to running outdoors for *you*.
Read the manual that came with your treadmill. I don't know any treadmill that can't be programmed to go up to at least 10.0. Most can be programmed up to 12-15mph. It's just a matter of knowing how to program it...:) You'll have to access the Maintenance Settings or some other Settings menu. Most treads come preprogrammed with a top speed of 9-10mph though the motor can go higher.
Alan
A 3% would do it. The slow component of VO2 is larger in incline running, so you would be working harder and harder as you go, using more and more O2 with just a steady pace. You could also use METS or calories as a guide, but again this is a bit off, since it assumes steady state, and similar VO2 kinetics during flat and incline efforts.
The feeling compared to land is nothing the same really. Incline running favors a ST type strength runner lacking speed. Oxygen cost is going to be higher, perhaps w/ less effort for the same METS simply because VO2peak is often higher on an incline due to the additional muscle mass involved. Matching it up on VO2 cost alone is simplistic, but even with RPE there are nuances you'll understand 2' into the workout.
RPE is still the easiest option. A tough 24' hill run is still a worthwhile workout and good prep for flat tempo training, simply because the concentration it will demand.
First measure the running belt length very accurately. Then when running on the treadmill have someone time 10 belt revolutions (best to make a white mark on the side of the belt with white out so you can easily time the belt revolutions). Knowing the distance of 10 revs and the seconds associated with that distance allows you to calculate exact TM speed (doing it with no-one on the mill doesn't give accurate readiings, because of the lack of friction your weight imposes on the belt). About every 5% incline will be like increasing speed by 1 minute per mile -- about 12 sec per mile faster demand for each 1% added. Try some combinations of speed and incline.