How To Use Rep Ranges To Develop Muscle, Strength and Endurance
When you train with medium reps (6-12) the adaptation is more metabolic and cellular and only moderately neurological. In other words when you train in this rep range you will get bigger and stronger, but the strength gains are not maximal like in the training with lower reps (1-5).
This is why that rep range is the most recommendable for bodybuilding and hypertrophy.
When you train with higher reps (13-20+) the adaptation is mostly on metabolic and cellular level. This rep range stimulates the local muscle endurance and small hypertrophy in a certain cellular components (sarcoplasmic hypertrophy) like the mitochondria and the capillaries and very little strength.
There is no clear dividing line where neural adaptations end and metabolic/structural begin.
For example when you train in 6-8 rep range the adaptation is somewhere neurological and metabolic/structural. In this rep range you get great strength gains and also great hypertrophy. In the 8-12 rep there is still neurological adaptation but less from the 6-8 range and much less than 1-5 range. This is the rep range that will give you maximum pure hypertrophy. You will also get stronger, but not so much like with the lower rep ranges.
|Rep range||Percent of 1 rep max||Training Effect||Goal desired|
|1-5 reps||85-100%||Neurologic||Strength & power, little hypertrophy|
|6-8 reps||75-85%||Neurologic & metabolic/Structural||Strength & Hypertrophy|
|9-12 reps||70-75%||Metabolic/Structural & Neurologic||Hypertrophy & some strength|
|13-20+ reps||60-70%||Metabolic/Structural||local endurance, some hypertrophy, little strength|
So if your goal is to develop your strength and power the larger part of your training must be in 1-5 rep range.
If your goal is bigger muscle mass and more size the majority of your training must be 6-12 rep range, but you should also do a little bit of training in the 3-5 rep range to build strength and power which will later help you to build more size by increasing the working weights and the stress on your muscles. You should also do a little bit of training in 13-20+ rep range to build mitochondrial density and increase capillarization (sarcoplasmic hypertrophy) and to stimulate the slow twitch muscle fibers to grow.
If you want to increase your endurance stay in the 13-20 + rep range and emphasize on aerobic training.