How to Maximize Muscle Growth, Part 1: Exercise
In this 2-part series, I will go over how to best use exercise (part 1) and nutrition (part 2) to maximize muscle growth.
Welcome to The Spotter!
I am Nolan Vannata. This newsletter is a part of my mission to make health, fitness, and nutrition content that is evidence-based, digestible, practical, and accessible.
Benefits of increasing muscle mass
The benefits of increasing muscle mass go beyond athletic performance and trying to look good. The health and longevity benefits of having more muscle mass are shockingly significant.
Before I highlight the health benefits, I must state that I don’t mean to diminish reasons such as athletic performance or trying to look better. Athletics have had a massive positive impact on many lives, including my own. Also, increasing muscle mass to look good has given people confidence boosts and changed lives from this perspective.
In the literature review, Live strong and prosper: the importance of skeletal muscle strength for healthy ageing, the authors demonstrate the strong correlations between increased muscle mass and life span.
As you see in the figure above, muscle mass reduces the risk of both all-cause mortality and cancer mortality. After the age of 60, these mortality rates are twice as low for those in the upper third of muscle mass compared to the lower third.
I need to you to read that again to emphasize how insane that statistic is.
After the age of 60, mortality rates are TWICE AS LOW for those in the upper third of muscle mass compared to the lower third.
Lower mortality rates are also correlated with high cardiorespiratory fitness, but that topic is for a different day.
There are many reasons to try to increase your muscle mass. If you want to do this, there are two primary areas to consider:
Exercise for increasing muscle mass, covered in this article.
Nutrition for increasing muscle mass, which I will cover in the next article, part 2.
Exercise for increasing muscle mass
While aerobic exercise (cardio) can be effective for increasing muscle mass, its efficacy for muscle growth is likely limited to those who are less trained or sedentary. When it comes to increasing muscle mass through exercise, resistance training will be your best friend.
I will cover three topics of resistance training for increasing muscle mass:
Load (how heavy the weights are)
Volume (how many sets you should be doing)
Exercise selection
Load: How heavy should I lift?
Before I start, here are some important definitions:
Intensity = weight, power, speed, etc.
Volume = reps, duration, distance, etc.
Intensity x Volume = Exercise or workout difficulty
You know this, even if you think you don’t. How many times can you do a bicep curl with 5 pounds? What about with 10, 20, or 30 pounds? Unless you are disobeying the laws of physics, you can curl the lighter weights for more reps than you can with the heavier weights. Although, if you curl each of these weights for as many reps as you can, they would be equally difficult because “as many as you can” means “maximal effort”.
There is a lot of debate on the best ratio of intensity and volume for optimizing muscle growth. In the case of resistance training, intensity = weight (usually), and volume = reps and sets.
The article, Loading Recommendations for Muscle Strength, Hypertrophy, and Local Endurance: A Re-Examination of the Repetition Continuum, aimed to bring science and data to this debate. Below is a common (and as you will soon find out, flawed) rep continuum. Also, the word “hypertrophy” refers to “tissue growth”.
The authors address this continuum and state,
“…the theory postulates that heavy load training optimizes increases maximal strength, moderate load training optimizes increases muscle hypertrophy, and low-load training optimizes increases local muscular endurance. However, despite the widespread acceptance of this theory, current research fails to support some of its underlying presumptions.”
Regarding muscle hypertrophy/growth, the belief that using moderate loads for 8-12 reps comes from anecdotes of bodybuilders commonly using this strategy. Research, however, does not support such a narrow window to optimize muscle growth.
As someone who likes to optimize and nerd out about exercise science, the conclusion is quite underwhelming. All loads above ~30% of your 1-rep-max (30% of what you can do for 1 rep) are equally effective at promoting muscle growth when taken to (or close to) failure. If you are unfamiliar with % ranges of your 1-rep-max, 30% is extremely light.
Volume: How many sets should I do?
I specifically only mention “sets” since we previously concluded the number of reps is somewhat irrelevant. This is because the number of reps you will do is dependent on load used.
This meta-analysis finds that muscle size has a dose-response relationship with volume, meaning that more sets = more muscle growth. interestingly, they did not find this same relationship with muscle strength.
Looking at many different studies, the authors conclude that high-volume training groups continuously gain more muscle than low-volume training groups. The total volume for groups is typically measured in “sets per muscle group per week”. The authors also mention that this finding is consistent with previous studies.
What defines high volume? There is no clear answer. Some studies had their highest volume groups performing 10 sets per muscle group per week, while others had the high-volume groups performing up to 30 sets per muscle group per week.
Personally, I don’t think “high-volume” needs to have a strict definition. If you are looking to maximize muscle growth, doing more sets is likely to help.
Exercise selection: What exercises should I do?
I will cover two questions here:
Single-joint or multi-joint exercises?
Machines or free weights?
Single-joint vs multi-joint exercises
Single-joint exercises are those that use 1 joint at a time. Bicep curls, knee extensions, calf raises, etc.
Multi-joint exercises are those that use multiple joints. Squats, push-ups, rows, lunges, etc.
The study below concluded that muscle growth is similar when comparing multi-joint vs single-joint exercises.
HOWEVER… The researchers measured muscle growth of the elbow flexors (i.e. the biceps). The multi-joint group performed lat-pull downs, while the single-joint group performed bicep curls.
With no large differences in bicep size between the groups, I would call this a win for the multi-joint group because of the fact they also likely grew other muscles that weren’t measured, like the lats and traps.
There are other studies showing similar results. I would view multi-joint exercises as a way to kill 2 birds with 1 stone, giving them my preference of the two. With that being said, single-joint exercises have their place in an exercise program, and I wouldn’t necessarily think of either as “better” or “worse”.
Machines vs. free weights
Machines generally use cables, pulleys, and levers attached to a weight stack to provide resistance.
Free weights are things like dumbbells, kettlebells, barbells, and have nothing attached to them. Free weights only rely on gravity and the mass of the weight.
I have heard many claims about free weights vs. machines and what they are good or bad for. I have even heard that using machines “isn’t real exercise” (which, in my opinion, is a stupid opinion).
The study below finds that both free-weight and machine-based training are equally effective on strength and muscle growth (as it states in the title).
When comparing free-weights and machines, just remember this: Your muscles are stupid and can’t tell the difference.
If you want to improve your back squat, then you should probably practice squatting with free weights. However, if you want to get better at the leg press, the leg press machine is better. Finally, if you simply want to make your muscles bigger, it seems that it doesn’t really matter if you choose machines or free-weights.
Summary
Load
Load seems to not matter when you take the load used to the same proximity of failure. Whether it is 5, 10, 20, or 40 reps, performing them to the same effort level will likely yield similar rates of muscle growth. If the last rep of your set is really hard, you will probably see results.
Volume
There is a dose-response relationship between the number of sets performed and muscle growth. The more sets you do within a given time frame (week, month, year) the more likely you are to gain muscle.
Exercise selection
When it comes to choosing between multi-joint and single-joint exercises, I would favor multi-joint exercises because it is more time effective. Rather than doing chest flies and tricep extensions, you could just bench press.
Although, I am a big fan of ending workouts with single-joint exercises to work on muscles that I feel were not targeted enough.
As for machines vs. free-weights, it doesn’t seem to matter. I recommend you try them both and see what you enjoy.
What is the mechanism for muscle mass reducing risk of cancer mortality? Seems crazy, just curious how that happens!
Love it!