1500m Free?

I am helping a masters swimmer train for the 1500m. I helped her previously for sprinting (2 years back now). Anyway I saw her in the pool and she trains by just swimming the 1500m.I was wondering if there were some other ways to train. Previously I have my swimmers do a 4 x 400 Free on pace.But I remember Dave posting awhile back talking about Hackett training a different way for his (this was during a discussion by Dave against doing pointless yardage). Any info on this?Lastly - a triathlon coach recently changed her freestyle to a straight arm pull. No scull at the start - just arm enters, elbow stays locked and goes straight through.Everything I know says that is horribly wrong - especially for a 55+ swimmer. Seems too hard on the joints to be effective and not enough leverage. But I also remember a friend of mine (a top level sprinter) saying he used this way and that it was faster for him as a 6'6" guy so maybe I'm way off base for this masters swimmer.Any help would be really appreciated.