charlie, what did you have ben do for his back? did you specifically focus on this area or is that just genetics mainly?
he did deadlifts early in his career I believe. That would put some meat on your traps and erectors
the lat pull downs as well, and his explosive start probably worked his back quite well.
For the spinal erectors: Gleut-ham Raises; Reverse Hypers; Squats etc
Did he ever do side bridges? Does anyone else incorporate this exercise into their routine?