Hypertrophy guide: My insights based on exercise science literature and the Chris Beardsley/Jake Doleshal “Hypertrophy Past and Present” podcast

Volume 1 - Frequency, volume, and intensity

When it comes to hypertrophy, or the growth of a muscle, there are three pillars of importance to be considered. These pillars consist of frequency, volume, and intensity. Starting off with frequency, which is the amount of times a muscle group is trained per week, the old school of thought was that frequency didn’t matter as long as weekly volume was equated. The 2017 Brad Schoenfeld study on the inverse dose response relationship between volume and hypertrophy confirms this, as it was shown that up to 52 sets per week for a muscle caused more hypertrophy. The frequency did not seem to matter, and the sole driver of hypertrophy in this instance was seen to be volume. This caused a frenzy among the science based lifting community, as many were distraught by the 3 hour per day sessions they must need to accomplish such volume. However, with outcomes there must always be mechanisms that drive them. A mechanism we know to be true is that strength and hypertrophy are closely correlated, as they are driven by very similar bio-mechanical processes. From Schoenfeld’s 2019 meta analysis, we see that strength gains cap at about 4-6 sets per week, but hypertrophy exists all the way through 52 sets per week. Due to this difference, many people, such as myself, became skeptical of this result.

Before delving into the more recent scientific literature, the first reason why this study was an issue is that many of the analyses used untrained lifters, and in hypertrophy data this simply cannot exist. To put this into perspective, imagine if you were to collect a study on distances produced by different golf clubs, but you used untrained golfers that had less than a month of experience with the sport. When comparing a driver with a nine iron, you may not always notice that the driver outperformed the iron. In fact, an iron is usually easier for beginners to control, and the results may even show that the iron often outperformed the driver instead. With trained golfers on their other hand, who have been playing for many years, the driver will likely outperform the iron 99 out of 100 times, showing a much more consistent line of data.

Bringing this back to our discussion on hypertrophy, trained lifters must always be used in these studies in order for results to be seen as accurate, or even taken seriously in the first place. The second reason why this study was blown out of proportion was due to the counting of indirect sets. This is much less of a lack of understanding of the mechanisms in place, but more so an issue with the actual execution of the study. A set of bench press, for example, would be counted as half a set for the triceps. Although the triceps are trained a decent amount in the movement, they are definitely not the prime mover of the exercise. Things like this can seriously affect interpretation, as many of the 52 “optimal sets” were only from indirect stimulus. However, these issues are more so related to the execution of the study rather than a contradiction of mechanisms at hand.

The contradiction lies in a lack of acknowledgement of muscular edema as well as a differentiation between sarcoplasmic hypertrophy and myofibrillar addition. For one, sizes of muscles were taken within 48 hours of training within many of the studies presented in the meta analysis, and we know that muscular edema, or intramuscular swelling, can be present up to 72 hours after training. Furthermore, higher volumes will certainly cause greater amounts of muscle damage, leading to a greater degree of edema present. Secondly, we must consider both sarcomerogenesis, and be able to differentiate from the addition of real contractile muscle tissue. When higher volumes are used, there will be greater degrees of sarcomerogenesis present, another “temporary” form of hypertrophy that causes swelling or larger appearance of the muscle. So as a whole, the high volumes used in this study were clearly unrecoverable, leading to high degrees of muscle damage and swelling, leading the researchers to believe that muscle size increased, when in reality the muscle was swelled to a significant degree during the time of measurement. In more recent analyses using recoverable volumes and with the help of Chris Beardsley’s Weekly Net Stimulus Model, we can see that one set performed twice a week would outperform 6 sets done in a singular session for that muscle group. This would mean that a set of a bicep curl on Monday and Thursday would yield greater gains compared to six sets of that same curl on Monday. The only mechanism explaining this is the rate of atrophy, and that the rate of atrophy is much quicker than we previously thought. Atrophy is the shrinkage of a muscle, and clearly occurs within 48 hours in order for this to be possible. The maintenance literature confirms this, as we can see that three to four sets completed once a week maintains a muscle, while three sets done on three separate days causes significant growth.

So how can we apply this? Since frequency clearly matters more than volume, we want to be hitting a muscle at least twice a week, preferably three times a week for best results. It is still a debate within the scientific community of whether two versus three times a week frequency would yield different gains, but for the majority, having at least two times a week frequency will be optimal. In terms of volume, since we know that strength and hypertrophy are closely correlated, and that strength caps at 4-6 sets per week, we would likely want to perform near this amount per week for maximal gains. However, I personally recommend 4-10 sets per week per muscle for most since multi-sets done multiple times a week have been proven to be better than single set approaches. This is because the stimulus of one set is only elevated 28-29 hours post training, meaning that atrophy will have been occurring prior to your next workout for a significant period of time. In terms of intensity, the current literature is showing no significant difference in training 0-2 reps in reserve, so as long as you are training relatively close to failure, you should not have to worry about getting proper stimulus. Leaving one rep in reserve might actually be smart, as you eliminate the most fatiguing rep and allow greater room for progression.

As a whole, the common crowd should simply focus on hitting a muscle group at least two times per week, training relatively close to failure, and performing 4-10 sets per week per muscle group. As a beginner, I would recommend closer to the 10 sets rather than 4, but as you get more advanced, and are reaching for high threshold motor unit recruitment, I would recommend a three times frequency per week with 1-2 sets per muscle per session, as the diminishing returns from greater amount of sets will provide little to no stimulus for higher degrees of fatigue.