I've got a almost 2 months of HRT down so I wanted to give some impressions and start a bit more conversation on the finer points of training.
Variables I've been playing with:
Rest between sets
Total work volume
Rest between exercises
Number of warmup sets
% of 1RM used for working sets
# of forced negatives
amount of force for forced negatives
Rep speed during concentric phase
In general, it seems that my greatest size gains were made when I was slightly sandbagging on the working sets and saving the force for the negs. For example - I can handle BORs with 325 for 8+4 right now. I'd (theoretically) be making better gains if I dropped to 305 or even 275 and work the 8 reps more explosively and then had my partner really nail me on the forced negs.
For my biceps, I've been ego lifting a bit and running right at my limit for the concentrics and my gains have been minimal (compared to the rest of my body.)
In comparison, I've gone a little (relatively) lighter on the tricep stuff and I've had great gains. My skullcrushers and overhead extensions have even gone to 5 negs before.
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Rest: I typically rest between working sets until my heart rate settles. I tried working it a little quicker and getting the rest down to 2-3 min but I didn't feel like I was in the groove for it. Even dropping the weight 10% still had me unable to really muster the force needed to resist on the negatives.
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Number of warmup sets: I know I'm atypical in that I need quite a few warmup sets to get things going. With HRT I also add in 1-2 moderate warmup sets (active rest) when swtiching exercises (with 60 to 80% of my working weight) which seems to help increase the mind-muscle connection. When we haven't done them, I've notice the both my training partner and I have poorer set performance and less DOMS. My weight also changes less (or not at all) during the 2 weeks I've been experimenting with it
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Thats about it so far. Nothing is conclusive yet and I don't want to pretend you'll get the same results. This is just the stuff I've noticed.