seriously, the trick is understanding that you must give everything you got for a short time in an effort to hang and catch up with the pac. Once you get caught up you instantly reduce effort by 30%. In racing it is important you know your coarse and anticipate the moves so you can be near the front when the acceleration happens. Otherwise it is easy to accordianed off the back. You were smart not to lead the pac at the start of the ride, as you understand the dynamics of the group you will better understand at what point in the ride they get frisky. Be near the front at this point from now on.