He was a believer in the HIT style training. Was one of the few doing it on a professional level back then.
Years ago I made some changes to my training by splitting it into three phases over a year's time. The first phase is HIT style. When I saw the training program Phil charges $300 for, I was surprised how closely to it I had designed my own HIT phase. It was about 98% the same with only a couple exercises changed (since I don't do close grip bench or dips)