A little over 2 years ago, I did major damage to my right ankle (forced to run with pain and an extensive history of previous injury to the joint). It was recommended that I not run for at least a year to allow everything to heal. Once the year was over, I've tried running off and on but without much luck. I'd run for a while, my ankle would become tender and I'd lay off. Recently, I've been going to a gym that has a nice treadmill. It has a nice long, wide platform to run on and has some type of cushioning system. I've managed to run/walk now for two weeks without any problems and I'm up to 2.75 miles with warmup/cooldown. What I want to know are the long term implications for doing all my training on the tread mill. (I have to run 1.5 miles twice a year for work and need to keep that time reasonable, say less than 12 minutes.) Any advice or comments????