Author: Adam Ibrahim


As far back as Lebron’s hair line, people have been promoting the idea that low reps (1-6 reps) were ideal for gaining strength, moderate reps (8-12 reps) were best building muscle, and high reps (12+ reps) were best for building endurance.  So, let’s ask ourselves the million-dollar question before diving into the literature and that is, what the heck makes muscles grow in the first place?

The How

The two major mechanisms of muscle growth that are in a constant battle with each other are mechanical tension and metabolic stress. More of one generally means less of the other. In other words, when you add weight to the bar, you induce tension, which usually means you can’t do as many reps, so metabolic stress is lower. When you take weight off the bar, you can cause more metabolic stress, but muscle tension is lower. Just by understanding this, you think training across a broad range of rep ranges would be effective.

That’s where effective reps play their part. Research has shown that you activate high threshold motor units when you go to or near failure. This means that you’re struggling to do these last few reps. When the bar speed is slow, your muscles have to exert maximal force in order to perform the movement and that’s what triggers muscle growth.

The Science

So now that we understand what causes muscle growth and what effective reps are let’s dive into some of the science.

One of my personal favorite studies showing us that metabolic stress and effective reps drive muscle growth was done by Count and colleges (2016). In this study there were 2 groups, one group that lifted with 70% of their 1RM and one group that used no load.

Yes, you read that right, no load. The no load group was told to maximally contract their biceps through the full range of motion for 20 repetitions, as the 70% group did anywhere from 8-12 reps which is thought to be where the magic happens. Interestingly enough, at the end of the 6 weeks both groups had equal growth in their biceps.

Another study that looked at two polar opposite type of training styles from Schoenfeld and colleagues (2014). These two groups were either assigned to a bodybuilding type training program or a powerlifting type training program. The bodybuilding type of program consisted of 3 sets of 10 reps with 90 secs of rest, while the powerlifting type of program consisted of 7 sets of 3 reps with 3 mins of rest.  At the end of 8 weeks of training, there were no differences between groups when measuring muscle growth.

The Coaches Hat

At this point, it’s time to take the white coat off and put the lifter/coaching stringer on. Through my experience as a coach, lifter, and student instead of asking yourself, “is this rep range better than another rep range?” You’re better off asking yourself, “what allows me to get in the most high-quality sets during each session and each week?”

For some people, heavy sets will burn them out and after a couple of challenging sets they feel fried and the rest of their workout and day suffers. For others, sets of 12-20 plus will just crush them metabolically, especially for exercises like the squat and deadlift. They just can’t get in much high-quality work after a couple of hard sets.

In other words, some people end up with beat up joints if they lift too heavy, and other people are left pressing their life alert button when they train with higher reps.

Being able to maximize hard sets within a training week will depend on what you best recover from between sessions and how they are structured day to day. With that in mind, your goal should be to find the rep range for each lift that allows you to get the most high-quality work in.


1. Counts, B. R., Buckner, S. L., Dankel, S. J., Jessee, M. B., Mattocks, K. T., Mouser, J. G., … Loenneke, J. P. (2016). The acute and chronic effects of “NO LOAD” resistance training. Physiology & Behavior, 164, 345–352. doi:10.1016/j.physbeh.2016.06.024

2. Klemp, A., Dolan, C., Quiles, J. M., Blanco, R., Zoeller, R. F., Graves, B. S., & Zourdos, M. C. (2016). Volume-equated high- and low-repetition daily undulating programming strategies produce similar hypertrophy and strength adaptations. Applied Physiology, Nutrition, and Metabolism, 41(7), 699–705. doi:10.1139/apnm-2015-0707

3. Schoenfeld, B. J., Ratamess, N. A., Peterson, M. D., Contreras, B., Sonmez, G. T., & Alvar, B. A. (2014). Effects of Different Volume-Equated Resistance Training Loading Strategies on Muscular Adaptations in Well-Trained Men. Journal of Strength and Conditioning Research, 28(10), 2909–2918. doi:10.1519/jsc.0000000000000480