Everyday I am asked by fellow weight training fanatics, “Why can’t I grow anymore?” Although the answer to this question can be quite complex and be the result of many factors, I often find the following commonality amongst those that have “hit the wall” on muscle growth: They use the same rep range week in and week out! While it is largely accepted that 1-5 reps build strength, 6-12 reps builds size, and 13 –20 reps build endurance (or in the case of the truly ignorant…definition), this is far too broad a generalization and also, not entirely accurate.

While muscle fibers are basically broken up into two categories, fast and slow twitch, it is important to remember that there are several sub-types of each of these fibers…a few of which share some of each others characteristics. It is true that fast twitch fibers have the greatest capacity for muscle growth, but unless you fully tax ALL available muscle fibers you will never succeed in reaching your potential! Further, if you only utilize one basic rep range, your body will adapt to that specific form of stress and begin to become non-responsive to your efforts. YOUR BODY IS AN ADAPTIVE MACHINE!

It should also be noted that muscles get larger through other mechanisms aside from actual fiber hypertrophy. Higher repetitions can increase capillary beds and enhance the ability of your cells to store more nutrients, which can actually “swell” their size.

While this little lesson in physiology can go on quite a bit longer I’d rather you focus on the take home message here: Vary your rep ranges. While the majority of your sets should fall in a range of 7-12 reps, your program should also include lower rep sets (3-5) and higher rep sets (12-16). This is something that can be done within the structure of each workout or can be done in a “periodized” fashion. My preference is to get the unique “feel” of each rep range within the same workout. The way that a 3-5 rep set makes your muscle feel is entirely different from how a 12-16 rep set feels. The pump you get from this type of training is outrageous and plateaus rarely occur because you are constantly changing the stimulus. Here is a sample chest workout:

-Bench press…3 x 3-5

-Incline dumbbell press…3 x 6-9

-Incline flye…2 x 7-12

-Cable crossover…2 x 13-16

So, if you are feeling stale and failing to get much out of your workouts, try throwing off your muscles and CNS a little with some new stimuli in the form of varying rep ranges. You’ll be glad you had a rep range revelation!