back to the gym... again

I have been having really bad luck with the running machines at my gym recently.

Now..... today I am due back and am going to use only the new machines. I am worried hat my times have been wrong because of the old crap I was using.

I am hoping to run 4 miles but we shall see. Previous attempts indicate that I can do 4 miles in sub 30mins, which is ok. I really want to build my strength on this and get myself up to a strong level.

What distance do you run?