By: Aaron Thomas, MA, CSCS
What Is The Optimal Rep Range For Hypertrophy
When training for hypertrophy it has been commonly understood that 8-12 reps is the best rep range. There has been a ton of research over the years that suggests this, and logically it makes sense. This rep range promotes the two main drivers of hypertrophy, mechanical tension and metabolic stress. Because of this, anything less than 60% of 1RM has been seen as less than optimal.
Recently, more evidence continues to emerge that suggests low load training, particularly with Blood Flow Restriction (BFR), can create an equal hypertrophic response compared to high-load training. The theory behind this is based on the Henneman’s Size Principle. This principle suggests that Motor Units (MU) are recruited from smallest to largest. Meaning, that smaller Type I fibers are recruited first. As they begin to fatigue, larger MU must be called upon to help generate enough force to lift the weight. By the time failure is reached nearly all MU have been recruited and fatigued. Despite using lighter loads, similar amounts of muscle fibers are ultimately recruited. The biggest downside here, is that you must lift the weight to or very near volitional failure. This can be rather painful. Some research also suggests that the “pump” that is created by performing very high repetition sets acts similar to BFR training, by trapping metabolites in the muscles being worked.
A recent meta analysis by Schoenfeld, “Strength and hypertrophy adaptations between low- versus high-load resistance training: A systematic review and meta-analysis“, found that high-load training lead to a greater increase in 1RM strength than low-load training. However, in regards to hypertrophy, there was no significant different between low and high-load training. Interestingly, his meta analysis also revealed that low load training may preferentially increase Type I fiber size, and high-load training may preferentially increase Type II fiber size. This is especially important, because it indicates that for maximal hypertrophy we likely need to include both in our training.
Now that we have determined that both types of training may be beneficial, how should we incorporate them into our training program? The answer to this question will largely be determined by our sport and our training season.
For powerlifters, the number one goal of training is to be able to lift more weight. At first, it may seem that there is no reason to perform low-load training, because the research suggests that it produces inadequate strength gains compared to high-load training. However, these are mostly short term studies. There is strong evidence to suggest that muscle Cross-Sectional Area improves strength. So, Type I fiber hypertrophy should still help you lift more weight. Knowing this, there are two really good times to incorporate low-load training:
1) Immediately following a competition cycle. Your joints are likely beat up, and the low-load training will give them some relief. You’ll likely be ready for a hypertrophy phase, so this will allow you to add some new hypertrophic stimulus while recovering connective tissue.
2) Following or working through/around injury. Sometimes you get minor injuries and tweaks. Its not always a great idea to continue to push really heavy weight. There may be some exercises that you have to do (Squat, bench, deadlift), but you might be able to sub out some accessories for a low-load variation to continue to progress while keeping injury risk low.
For bodybuilers, low-load training can be used at almost any time in their training cycle. Low-load training should probably be used in the latter half of your workout. This likely allows you to get the most beneficial heavy training volume in at the beginning of your session to stimulate more Type II fibers. So, start with your heavy compound exercises, then finish off the workout with a couple low-load isolation movements, like cable flies and cable tricep extensions to failure.
Another great time for bodybuilders to use low-load training is near the end of a contest prep phase. When you are extremely lean, and your calories are extremely low you tend have a lot of chronic fatigue. Your injury risk is much higher at this phase of training than any other time in your training cycle. Rather than trying to squat and deadlift 85% 1RM at 1 rep from failure, it is probably a bit smarter to sub them out for lower-load, more isolated variations. Very high rep leg press and db hyperextension can be a great way to minimize injury risk while maximizing muscle retention.
Since I didn’t emphasize this much before, just remember, you HAVE to approach muscular failure to get much out of low-load training. This will SUCK. It can be extremely painful, but if you like feeling the burn, you’ll love it.
If you got anything out of the article above or would like to read more articles by Aaron, continue checking out our Aplyft Blog, or go check out his website www.strengthalytics.com. You can also follow him on instagram @1atperformance or @strengthalytics
“I am coach with a passion for helping others achieve their best performance when it counts. To do this, I use a data driven approach, backed by the scientific literature and years of anecdotal experience. Over the years, I have worked with powerlifters, bodybuilders, as well as hundreds of D1 and professional athletes. I specialize in working with powerlifters and bodybuilders who are dedicated to reaching the top of their sport. With over 10 years of experience, thousands of hours of research, and several USAPL and IPF gold medalists, I am confident than I can take you to the next level.”
Aaron Thomas, MA, CSCS