I have a theory that I just implemented into my training, makes sense to me, tell me what you guys think.
My idea is that when working one body part per day, say three exercises, you use three different lifting techniques, lower reps heavy (5-8 reps), another exercise 8-15 reps, and the third an explosive technique low reps (3-6) a la The Perfect Rep. Then the next week, same exercises however different lifting technique.
This way, throughout two to three weeks all possible muscle fibers are hit. Here is an example
Flat Bench 5x5
Decline Dumbell 7 x 4 (perfect rep style)
Flat Bench 7 x 4 (perfect rep style)
Decline Dumbell 4x12
(I would never do flyes heavy 5x5, but you know what I mean).