There still seems to be a lot of confusion these days between the worlds of strength training and hypertrophy training, and how the two are interconnected—similar yet completely different at the same time.
A brief scan across the internet will make you believe that simply shifting your rep scheme from 6-8 reps to 10-12 will some how magically “trick” your body into believing that you are now trying to build muscle, as opposed to trying to get stronger.
But it’s not that simple.
The differences between strength training and hypertrophy start deep inside our bodies, at the physiological level.
If we can first have a base level understanding of the mechanisms involved in the two, and then how our individual bodies are genetically predisposed to respond to one versus the other, then we can really take an educated approach to our training, and ultimately bridge the gap between strength training and hypertrophy.
Strength and Hypertrophy, Defined
To get there though, we must first start with defining what strength and hypertrophy are.
Webster’s Dictionary defines the two the following ways:
- The state or quality of being physically strong.
- The capacity of an object or substance to withstand great pressure
- The enlargement of an organ or a tissue from the increase in the size of its cells.
Based on the definitions alone, we can reiterate what we may already know: strength means you can lift heavy stuff and hypertrophy means lifting heavy stuff makes your muscles get bigger.
In order to understand why this happens, let’s start by discussing kids who lift before they hit puberty. While we probably all knew the kids who seemed to have a natural six-pack and were already cut up, they probably didn’t look all that big.
When a kid starts lifting weights or performs resistance training before the reach a pubescent age, they are taking advantage of their neural pathway’s capacity to be educated to fire appropriately.1
While this might cause them to see an increase in strength, they likely won’t see a very significant increase in their hypertrophy. Why is this?
The answer is simple—hormones.
Yes, those things we all remember controlling our lives for what seemed like an endless amount of time.
Hormones, especially testosterone stimulated by gonadotropin releasing hormones, are what give individuals the capacity to increase in size (sometimes for better or worse).3
The age-old question now is why don’t all who have adequate testosterone levels see the same increases in size? Unfortunately, this is more of a matter of genetics than anything else. There are a number of theories about why muscles increase in size secondary to resistance training.
Below are the three most common beliefs:
- Resistance training causes a sustained increase in the blood flow that muscles receive, causing the muscle fibers to essentially swell.
- Resistance training causes an increase in the number of muscle fibers, creating more fibers in response to the demands of their loads.
- Resistance training causes an increase in the diameter of muscle fibers themselves.
The most up to date research we have available shows us that these first two theories really have no real holding. While blood flow does increase in response to resistance training, this is not sustainable for our cardiovascular system and would cause our hearts to be under an insane amount of stress.4
This is why choosing to take that post-gym swole picture would look a lot better within the first fifteen minutes rather than an hour later. Our cardiovascular system is able to regulate back to a state of homeostasis, rather than being under a prolonged stress.
In terms of increasing the number of muscle fibers that we have, that’s really not possible. Genetically, we have a pre-determined set of muscle types (Type I, Type IIa, Type IIb, and some even say Type IIx).5
The Role of Muscle Fibers
The number of muscle fibers we have is part of the reason that not all individuals see a massive increase in terms of hypertrophy. Those who have more muscle fibers available are going to see better results when are performing resistance training, thus taking advantage of their natural production of testosterone.
While this one factor, there are two others to consider.
The first is type of muscle fibers an individual has available. If an individual has predominately Type I muscle fibers, also referred to as slow-twitch, they will have a lesser capacity to pack on size.5
Because these muscle fibers are designed more for endurance, they will be unable to have more rapid increases in size and load capabilities as those that are Type II, especially Type IIb and Type IIx.5
These fibers are able to take advantage of our creatine-phosphate (CrP) system to a much high degree, benefiting from the increases in size associated with training within this system’s zone.6
In terms of how testosterone affects these muscles, research has produced a couple of main theories but the physiology community has widely accepted that the bio-chemical mechanism is rather poorly understood. The best efforts have led many to accept that testosterone increases fractional protein synthesis, allowing proteins to assist the muscles in growth through recovery.3
The Strength Gain
Now, in terms of individuals who gain strength but maybe see less hypertrophy for their efforts, there are several key factors to consider.
First is the SAID principle and this applies to anyone who is performing resistance training, or training of any kind (SAID stands for specific adaptations to imposed demands). This translates to saying that the human body is pretty incredible and will respond favorably to the demands, or load, with regard to resistance training.
When an individual takes part in a resistance training program, they will still see an increase in size even if they may not see the same increase in muscle “swelling” as their friends who are doing the same program. While the increase in hypertrophy may not be there, the increase in strength will happen. Regardless of whether or not their muscle fibers have the same growing capacity as others, they are still capable of taking advantage of proper neural pathway firing.
Additionally, for individuals who are looking to increase strength, it is important to use proper muscle recruitment. This is especially important when performing dynamic exercises such as the bench press, deadlift, and back squat.
For example, when fixing one’s feet and focusing on externally lifting at the hip joints, the lateral musculature of the hips provide an added level of stability that will help an individual lift more weight than they would otherwise be capable.
The same premise applies when getting into a true hip-hinged, braced-core position at the starting point of a deadlift. The stronger and more activated the core, the more stability will be added during the lift and the less reliability there will be on the lumbar back muscles, which will generally be a week point along the posterior chain.
This is not to say that individuals who are more apt to witness hypertrophy will have less of a capability to get strong because there are some very bug, very strong people in the world. Watch 30 seconds of any strongman event and that will become evident very quickly.
Choose Your Programming Carefully
Programming for either goal, or both, can be tricky and involve careful consideration with a trained professional. For less advanced individuals, starting with a high-rep, low-weight period, through a full range of motion at different joint angles, will allow for a true boost in the firing capabilities of the muscles.
It is for this reason that any time a program is new to an individual, especially a more novice lifter, they see a rapid increase in strength over the first six or so weeks. Their muscles are being educated and just like us, our muscles love to learn and will respond and grow.
After this point, the training really depends on the goal. If someone is looking to compete in a strength competition, there will be a long strength cycle that will involve multiple taper periods within the cycle. For those aiming for hypertrophy, there will be a more prolonged cycle that will see a larger amount of volume throughout the training period.
No matter what the goal, or whether you’re training for strength or hypertrophy, you will never be able to completely eliminate one from your training, your program must always include both. But hopefully after today, you have a better understanding of how the two work independently and together to help you reach your goal.