There isn’t a perfect rep range for growth. It’s all about total volume and intensity – not rep ranges.
Total Workout Volume (tonnage)
The tonnage of a workout is simply the amount of weight that has been lifted. For instance, 3 sets of 10 reps with 100lbs equal 3000lbs (30×100) total volume.
This is a very important number, and yet many people have never heard of it.
If your overall workout volume is increasing, you are subjecting yourself to more stimulus. As a result, your body is adapting one way or another. If the weight is heavy enough (high intensity), part of the adaptation will be in the form of growth and strength increases. Therefore, pushing your total workout volume upwards should be your main priority – not doing a precise amount of reps.
Some of you may get the impression that one should simply aim to reach a specific number while sacrificing intensity. This is not the case.
Let’s say that your 1 rep squat max is 200lbs. This means that your 5 rep max is about 150-170lbs depending on the lift. 5 reps with your 5 rep max would equal about 750lbs lifted. On the other hand, lifting 110lbs 7 times equals 770lbs lifted. However, it’s much easier to do 110lbs x 7 than 150lbx5 when your 1 rep max is 200lbs. In other words, if you sacrifice your intensity, the adaptation would not be as profound.
The goal is to keep both, the volume and the intensity, moderate to high. How you do that is a personal preference. You can do 5×5, 10×3, 2×8…etc. As long as the overall tonnage and the intensity are sufficient, progress will occur regardless of the rep range you follow.