The reason for the shorter run-in is because it allows an athlete to do a couple more reps, and allows the focus (relatively speaking from a standpoint of volume) to be more on the top-end zone rather than the acceleration (even if it’s sub-max). With my sprinters I’ll extend the zone to 40m but with jumpers I usually keep it at 30-35 depending on the athlete because they’ll never see lead-ins nearly that long in a competition and in general are great accelerators to begin with.
We always do our flys with sub-max accelerations however we also do sprint-float-sprints and occasional short speed endurance work (50-70m) in which the athlete definitely hits full out top-end speed.
ELITETRACK Founder