I've been doing all my training runs and tempo runs in the asics ds trainer 14 but have recently been increasing my mileage and have been having a few small knee and foot problems so today I bought a new pair of asics gel 1140's to get a little more support. I've been wearing them today just walking around and stuff but I was wondering if breaking them in on a 50-60 minute run would be to long of a break in run. I have my long run saturday but didn't know if that would be to early to wear them. I didn't know since they are about an oz. Heavier than the ds trainer I've been wearing if i should take a little longer to break them in? Also, I have the first race of my xc season on tuesday and didn't know if swithcibg now would have any effects on my racing?