Maximal Muscle-Building

            Building muscle is one of the healthiest and most functional things that any human beings can do for themselves. The benefits range from increasing BMR (and allowing you to eat more each day) to improving longevity and quality of life in the elderly. Body composition, in general, is why the vast majority of people are in the gym in the first place.

            The problem is that most people simply don’t have the information to put together training programs for themselves that will effectively put muscle on their body. In this article, I want to address the three primary drivers of hypertrophy, and how different training variables and techniques can affect each one. 

Factor #1: Mechanical Tension

            Mechanical tension can be thought of simply as the force that we put through our muscle fibers when we subject them to resistance training. Scientific literature seems to have reached a consensus that mechanical tension is the primary driver of muscle hypertrophy, and we will consider it to be the most important of the three for our purposes. There are several ways we can affect mechanical tension in training. 

1A) Overload refers to subjecting muscle tissue to forces stressful enough to cause adaptations on a cellular level. In order to force a muscle to deviate from its preferred state of homeostasis, we must impose stress sufficient enough to disturb this peace and make that muscle adapt to become better at dealing with similar stressors in future.  

            Progressive overload refers to the incremental increase in resistance of an exercise over time. There are numerous ways to progressively overload a muscle or an exercise, but the most basic of these is to simply add weight over time. This gets brings up another point: that everyone seeking to add muscle mass should set performance goals, not simply outcome goals.

            Hypertrophy is a slow process, and it can be difficult to measure directly without expensive laboratory equipment and know-how. This is why setting goals for strength in the gym can be a useful tool. No, training for strength and training for hypertrophy are not the same thing, nor are they the same physiological process, but tracking progressive overload by keeping a dedicated log book is an excellent way to ensure that you are providing sufficient stimulus for your muscles to continue growing over time.

            Muscles can grow whether they are subjected to heavy loads, medium loads, or light loads. What matters more is the relative intensity of each set (how close it is taken to failure). That being said, while you should still include each one of these loading parameters into a program, research seems to indicate that the majority of your time is best spent lifting those medium loads (65-80% of 1RM, 6-12 reps) as they seem to be the most economical use of your time. 

1B) Volume is a measure of the amount of training you are doing (usually within a single training session).  You can calculate this by multiplying sets × reps, or more accurately, sets× reps × load (although technically this is volume-load).

            There exists a strong, dose-dependent relationship between the amount of volume being performed and the amount of hypertrophy that results from it. As such, people who want to maximize muscle mass (and how quickly they gain muscle mass) should seek to maximize the amount of volume they perform in the gym.

            This relationship, like so many others in the human body, only exists to certain point. At some point, you cannot expect to add more sets and see more progress. There is a point at which adding more volume will not only stop working, but in fact become detrimental. After this point (often called one’s maximum recoverable volume, a term coined by Dr. Mike Isreatel) the risk of injury increases significantly and progress may actually regress. 

            The take-home point here is that we should strive to increase volume load over time by progressively overloading exercises and by increasing training volume steadily. It is not a question of how much work you can perform—it is a question of how much work you can recover from. 

1C) Exercise Selection for hypertrophy differs quite a bit from strength training. When we are trying to move as much weight as possible, we want to take every biomechanical advantage we can: shorter ranges of motion, the use of momentum, and using as many different muscles to contribute to an exercise as possible. 

            In hypertrophy training, we actually often want to disadvantage ourselves as much as possible. The goal is always to maximize the mechanical tension and recruitment within the target muscle group, and this can be done by lifting with a slower cadence, focusing more on the contraction and less on the lift itself, and choosing exercises that allow us to train muscles in relative isolation. 

            For example, a powerlifter may choose a sumo deadlift to cut down the range of motion as much as possible, involve as many different muscle groups (like the quads and adductors) as he can, and get the most amount of leverage he can.

            Bodybuilders, on the other hand, typically favor conventional deadlifts or RDL’s instead. This is because this pattern has a longer range of motion and puts the muscles of the posterior chain in a slightly less advantageous position to apply force from.  

Factor #2: Metabolic Stress 

            Another potential mechanism of hypertrophy is the buildup of certain metabolites (namely hydrogen ions and lactate) in the muscles that results from hard training of certain duration. 

2A) Time under tension is often talked about in bodybuilding circles as a stimulus for muscle growth, and one of the primary reasons for this is because these type of sets typically last longer (~15-60s) and rely more on anaerobic glycolysis, which creates more metabolic stress and fatigue within the muscles. 

            While the idea of “constant tension” may have some merit, the duration of the set and the time the muscle is being worked seems to be more important than ensuring that there is never a lapse in tension. There are several ways to extend a set and cause a muscle to undergo more metabolic stress. Tempo sets and pauses at mid range are some of the most effective ways I have found to do this. Compare doing a set of walking lunges quickly to a set of lunges where you lower yourself slowly for three seconds, pause for two seconds at the bottom while holding tension, and contracting hard to stand back up. You can actually feel the how much more metabolic stress you have created in the second set—and it burns!

            Another method that should be talked about for maximizing metabolic stress is blood flow restriction (BFR) training, which involves cuffs or sleeves that restrict blood flow returning from the working muscles. This causes a massive buildup of metabolites very quickly and it has been shown to be able to produce muscle growth with lighter loads than are typically recommended. 

2B) Rest intervals are another way to manipulate the amount of metabolic stress from exercise. Shorter rest periods between sets (~30-90s) absolutely will produce higher metabolic stress, but it comes with a trade off: you wont be able to perform as well each set.

            With this in mind, we can structure our program accordingly. When we are trying to maximize mechanical tension and set PR’s, we want to rest for a longer period of time (2+ minutes) to ensure we are fresh and recovered. Typically this is early part of the session. When we are trying to maximize metabolic damage, we can rest shorter because the weight we are using on each set is less important. This can be done later in the session or even on a different day. 

Factor #3: Muscle Damage

            This refers to the actual damage done to the cellular machinery of the muscle fibers being worked, which requires repair after training. While some researchers believe that this is an independent factor that causes hypertrophy, others hypothesize that muscle damage is more of a byproduct of mechanical tension, and does not in itself cause hypertrophy. 

            What is clear is that too much damage can be detrimental to development, which is why I don’t believe that delayed onset muscle soreness (DOMS) is a useful indicator of hypertrophy. I believe the goal should be based around progression in the gym, not simply in causing enough damage to make yourself sore hope that it translates to growth. 

            Most muscle damage occurs during eccentric muscle actions, which are a part of almost any exercise we do in the gym. While there may be certain times, such as in the aforementioned tempo training, that we might choose to accentuate the eccentric contraction, I do not typically program overloaded eccentrics for very long periods of time, as they take a longer time to recover from. 

            I hope this has been a helpful guide to the different avenues through which you can expect to produce muscle mass, and that you will explore each one in your own training. If you are curious in reading more from experts in the field of hypertrophy, I cannot recommend enough that you read the works of the likes of Brad Schoenfeld, Eric Helms, Greg Nuckols, and Mike Isreatel.