Treadmill training help! 10 points!?

um... 10 mph is fast enough, nobody is going use that speed, 1.5 miles is nothing, anybody can do that in 15 mins if it takes you 10 mins for 1 mile, forget about the incline, using the treadmill too much can cause hurt the knees, i've heard people get surgery just cause of doing it for years. What should really matter is how many calories you lose, running outside is harder and incline will only cause knees to hurt so just do it at your paste. The fastest I can run for 1 mile is 7.5 mins, running outside is harder, depends also if there are hills, but I can do both, the trick is to learn how to control the breathing.