What kind of training protocol do you follow now and what were the improvements made after switching away from HIT?
I couldn't really follow HIT because when I read his booklet I was in high school and working out at home. I had a 300 lb Weider Olympic set and wobbly adjustable bench with an even wobblier squat rack attachment. I had no way to do forced reps which seemed, according to Mentzer to be a requirement.
By the time I joined a gym which I think was either Jr or Sr year of high school I was following Calta's Routine which was ~ 6- 8 sets per body part per workout
At the time my gym (in Lewisville Texas) had a big room and a small room and they opened the big room to men on M-W-F and the women got the small room and then they reversed it on T-TH-Sat. So it fit perfectly with Calta's routine. I probably gained about 25 or 30 lbs in those two years doing that but also, of course I was still a teenager so just gaining weight/size by getting older as well
Later on in college I followed Lee Labrada's split and training with was similar in volume to Calta's routine.
Mentzer's workout ideas in the 1990's were a much lower volume and frequency that he had previously advocated. They seemed kind of ridiculous.
At the present moment I do about 9-12 sets per bp spread over 3 exercise per bp