What is Functional Hypertrophy?


by Charles Poliquin

Muscle hypertrophy training, or doing resistance training that builds your muscles, is something everyone you wants to live a long, healthy, lean life should know about. Hypertrophy that is functional is not just for athletes, body builders, or young men. Rather, everyone will benefit from functional hypertrophy training because at its most basic level, this style of strength training will improve your body composition, make you more agile, mobile, and strong.

This article will provide a basic introduction to functional hypertrophy. It will also include a deeper look at more advanced strategies used for hypertrophy that I recently covered in the Hypertrophy Bootcamp at the Poliquin Strength Insititue in East Greenwich, RI.

What is Functional Hypertrophy?

Hypertrophy is the growth of muscle and occurs because the existing muscle fibers get larger due to strength training. Mechanical loading, or weight lifting, triggers processes within the cells and muscle fibers that lead to protein synthesis and muscle growth. Functional hypertrophy is muscle growth that is strategic so that it grows your muscles in a way that will improve physical performance.

For a sprinter, functional hypertrophy will involve training that is both heavy and fast to help the sprinter become more explosive and faster without inducing too much gain in total body weight. In comparison, a football defensive lineman needs to be explosive and quick but they also need to weigh a lot since they have to block and push players who weigh around 300 pounds. A lineman who is very strong who only weighs 180 lbs will get squashed by a 300 pounder even if the 180 pounder is stronger and can bench press more weight.

What is Functional Hypertrophy for Non-Athletes?

The definition of functional hypertrophy for non-athletes is the same as for athletes—it grows your muscles in a way that will improve physical performance. In addition to improving body composition and supporting metabolism, functional hypertrophy can help you get rid of chronic pain and prevent injury. It all has to do with which muscle fibers you grow with your training. Stronger type II fibers have been shown to decrease the risk of falls and fractures in older individuals. On the flipside, type II muscle fibers are more susceptible to loss of strength and size as we age, which produces a proportionately larger loss in power and strength. This puts us at greater risk of fall, injury, and poor physical performance.

There are two basic fiber types, type I and II, and they are each broken into subcategories. The type I fibers are called slow-twitch fibers and they produce low amounts of strength and power, but are very fatigue resistant. Endurance running or swimming will favor type I muscle fibers. The type II fibers are called fast-twitch fibers and they produce high amounts of strength and power, making you fast and explosive. They fatigue quickly. Within the two fiber types there are at least seven subtypes but for now all you need to be aware of is the distinction between type I and II.

If you’re a non-athlete, functional hypertrophy training will allow you to strengthen your type II fibers, which is essential for longevity. In fact, even elite endurance athletes such as marathon runners will benefit from strengthening their type II fibers. Endurance athletes who do a high volume of aerobic training won’t gain significant muscle mass even from a functional hypertrophy protocol because research shows aerobic training creates a muscle degrading environment that cannot be overcome with strength training.

But, a functional hypertrophy protocol done by an endurance athlete will increase the proportion of type IIA muscle fibers (one of the type II subtypes), which are fatigue resistant and more powerful than type I. This can boost performance now, but it will also set the endurance athlete up for better mobility as they age because research shows that if type II fibers are not activated at an early age, it may be impossible to activate them later in life. And the only way to activate the more powerful type II fibers is by strength training and doing explosive movements such as sprinting or jumping. Never having trained the type II fibers puts an individual at greater risk for muscle weakness and falls later in life.

Naturally, an endurance athlete’s functional hypertrophy program will be different from a tennis or football players program. An older individual’s functional hypertrophy program will also be different because it will be oriented toward improving physical performance, which in this case is probably focused on mobility and structural balance. Still, the theory of maximizing muscle fiber development for performance will guide the protocol.

What Are Other Benefits of Functional Hypertrophy for the General Population?

Neuromuscular strength is a primary benefit of functional hypertrophy training. Neuromuscular strength refers to how effectively your body recruits muscle fibers, particularly the higher threshold fibers, which are the type II fibers. Be aware that the general population often overlooks the importance of neuromuscular strength for daily physical performance and longevity.

The neuromuscular system includes the central nervous system, which is made up of the spine and sensory nerves, and the motor neurons, which activate the muscles to contract. When you build neuromuscular strength, you increase the efficiency of the signal that gets sent from the central nervous system to the muscle, making it contract with more force and strength.

In general, the type II muscle fibers are recruited after the type I fibers, meaning that for slow movements or the lifting of light weights, only the type I fibers will be used and only they will be trained and hypertrophied. When you lift heavier weights or perform explosive movements, the “higher threshold” type II fibers will be recruited, trained, and hypertrophied. Functional hypertrophy training will allow you to recruit these high threshold type II fibers for greater power and strength.

Be aware that the most common way to do this is by lifting very heavy weights that are close to the maximal amount you can lift, but it is possible to train the high threshold fibers with somewhat lighter weights and more repetitions that exhaust the motor unit. This will improve neural drive and make you stronger. For example, novice trainees, older individuals, children, and females with less training and strength will not get the greatest benefit out of near maximal weights.

Why Would Anyone Not Train To Maximize Functional Hypertrophy?

Excellent question. It is logical that everyone would want to exercise so that they develop muscle that makes them perform better in sports and everyday life, but a lack of scientific basis for training protocols has gotten in the way and produced misconceptions. For example, a common area that you don’t find hypertrophy being very functional is in body building. Body building is all about growing muscles, but body builders with the most impressive physiques may not be the strongest. For the general public and for athletes, a body building protocol would be pointless because these programs train you to get big, but slow and may produce muscle imbalances if the fast and slow-twitch qualities of different muscles are not accounted for.

For instance, the hamstring muscle is often lagging in the sport of body building and may be a weak link for many athletes. For the general population, poor hamstring strength and size can produce back pain and poor mobility. It puts athletes at risk of injury. The reason is that the hamstring is fast-twitch when it flexes the knee (a butt-kick motion), and slow-twitch as a knee extensor. Fast-twitch muscles respond best to lower reps and heavier weights, whereas slow-twitch muscles respond best to lighter weight and higher reps. Meanwhile, if you’re training for sports that require quickness and speed, you will want to train to be fast by including explosive movements in your protocol. Forced repetitions at a slow speed, a common component of body building hypertrophy programs, should be avoided.

Studies have shown that body building programs that use slow training movements will hypertrophy primarily type I fibers, whereas the fibers that are built by power athletes and Olympic weight lifters are type II fibers. Another difference between body building hypertrophy and functional hypertrophy is the part of the muscle cell that grows. This will sound technical but it’s an important distinction to understand.

An individual muscle fiber is made up of two components called a sarcoplasm and a sarcomere. Growing the sarcoplasm, or sarcoplamic hypertrophy, involves the increase in non-contractile proteins and fluids between muscle fibers so that the cross-sectional area of the muscle is larger, but the density of muscle fibers decreases. Sarcoplasmic hypertrophy won’t increase muscle strength and is a technique used by body builders since it makes their physiques more imposing.

Growing the sarcomere, or sarcomere hypertrophy, is the increase in the size and number of sarcomeres in the myofibrils, which make up an individual muscle fiber. Sarcomere hypertrophy increases the density of myofibrils that contract to make a muscle motion. This hypertrophy leads to greater strength. Sarcomere hypertrophy is generally what we are referring to when we talk about functional hypertrophy.

How Will functional Hypertrophy Support Optimal Body Composition?

Training for functional hypertrophy will support body composition because it is about maximizing relative strength for your weight, meaning that a primary goal is to get the most powerful , “usable” strength, while minimizing body fat. Carrying excess body fat or excess muscle mass in the form of sarcoplasmic hypertrophy will adversely affect endurance and places a burden on the cardiovascular system. This lowers athletic performance in most sports and almost all recreational activities. An often overlooked key to functional hypertrophy is supporting it with nutrition because this will allow you to boost metabolism, improve your insulin health and blood sugar levels, and support hormone response for fat burning.

What Do I Need To Know About Nutrition for Functional Hypertrophy?

Branched chain amino acids (BCAAs) are the most important nutrient for functional hypertrophy because they will elevate protein synthesis and recovery. If you’re part of the general population and are training for functional hypertrophy, BCAAs are just as important as for athletes because they will decrease soreness from lifting and speed the recovery process. They also improve insulin sensitivity, which is essential for maintaining energy levels and improving body composition. BCAAs are found in high-protein foods such as meat and whey protein and can be taken in supplement form.

BCAAs that are enriched with leucine (the BCAAs include leucine, isoleucine, and valine) are especially beneficial for older trainees, and of course older trainees are one of the populations that will benefit most dramatically from functional hypertrophy since they are most susceptible to muscle loss and poor mobility. Research shows that BCAAs with extra leucine will trigger a gene signaling pathway for hypertrophy in older trainees that is inactive unless leucine is present. Another benefit of BCAAs is that they support androgen receptor sites and have been shown to improve the testosterone to cortisol ratio, making you more anabolic.

The second most important nutrient for functional hypertrophy is glutamine, the most abundant amino acid in the body. Glutamine is the primary building block in the intestinal lining and it restores the intestines, improving gut health. It also lowers inflammation and supports digestion. For example, glutamine is beneficial if you have a stomach illness or are going somewhere with contaminated food and water such as Mexico. Take a very large dose of glutamine (60-plus grams) and it will heal and guard the stomach.

Glutamine also plays a part in immune function such that if you are getting sick, you should take a large dose and recovery will be dramatically accelerated. Researchers have recommended glutamine as a supplement for sick children and adults to speed recovery, and it is necessary for the body to heal wounds. I have found that muscle gains from training often correlate with how strong the immune system is. On the flip side, if you overtrain, glutamine levels will drop, catabolic stress hormones will rise and you will likely feel under the weather.

With all this data, it makes sense that it would also support recovery from intense training and a new study in the Annals of Nutrition and Metabolism showed that it does. Researchers found that glutamine is instrumental in tissue repair, and if there is a shortage, recovery from training will be impaired. Glutamine also accelerates muscle glycogen resynthesis making it beneficial for strength athletes but absolutely essential for endurance athletes whose performance is limited by glycogen stores and quick replenishment of this energy source.

Glutamine and BCAAs are both amino acids, but protein in dietary form should be the focus of your meals for functional hypertrophy. Following training, a large dose—called a bolus dose—is best to promote protein synthesis and recovery. I suggest protein supplementation as well, but I want to stress the value of whole foods protein and fiber for functional hypertrophy. Be sure to focus on getting ideal amounts of fiber from vegetables because they will provide antioxidants and low-glycemic carbohydrates, which are best for body composition.

For most people who are not endurance athletes, energy, focus, and drive to exercise will be better if you avoid carbohydrates for breakfast and before training. This does not apply to everyone, but in general, you want to avoid carbs for breakfast because they will suppress the production of neurotransmitters that give you energy such as dopamine and acetyl choline.

The same applies prior to strength training, which is where many people go wrong with nutrition. Eating carbs, especially high-glycemic carbs that contain a large amount of glucose and are digested rapidly will make you tired and elevate the neurotransmitters that make you lethargic and unmotivated. Be aware that the fuel you are burning when you are working out is what you ate in the past—although your energy levels and neurotransmitters will be influenced by what you just ate—because these nutrients have replenished cells and can support energy levels. For hypertrophy and the enhancement of protein synthesis, amino acids are ideal as you are training and immediately after—this is where BCAAs and glutamine come in.

Can You Give an Example of a Workout Technique For Functional Hypertrophy?

A functional hypertrophy technique that I teach at my Hypertrophy Bootcamps is the use of Giant Sets. A giant set is a group of four exercises that target one part of the body. For instance, a lower body giant set would be eccentric-enhanced squats, followed by heel-elevated squats to isolate the quads a bit better, followed by lunges, followed by trap bar deadlifts. This is an excellent way to shock the lower body into getting stronger and it will also train cardiovascular fitness. It triggers a robust anabolic hormone response and is particularly effective for boosting growth hormone and insulin-like growth factor-1.

Training giant sets and using related training techniques such as varying tempo is the best way to subject your body to something it’s not used so that it has to adapt. The variation of tempo is a complex training strategy in which you alter the amount of time spent on different parts of the lift such as doing eccentric-enhanced squats that use a slow tempo (4 to 6 seconds) for the down motion and a fast tempo (explosive) for the up concentric motion. To read more about varying tempo, there is a link to an article at the bottom of this page.

The Hypertrophy Bootcamp Sounds Interesting. What Else Would I Get Out Of It?

The Hypertrophy Bootcamp is a course that has students learning about the theories behind functional hypertrophy in class, and then has them train those methods three times a day for a week in the gym. I also cover nutrition for hypertrophy and always highlight the importance of BCAAs and glutamine. Aside from practical tools that you can use in designing your own and your athletes’ workouts, you realize that your body will adapt to anything you subject it to, and it needs to be challenging and difficult if you want fast, dramatic results. There is no 15-minute “quick fix” for body composition and getting in shape as many fitness magazine suggest, but it is possible to improve body composition rapidly if you eat right, supplement to support recovery and fat burning, and you subject your body to something it’s not used to. Most people do not work hard enough to elicit these rapid, dramatic gains. The Bootcamp will help you set a new mentality of what your body is capable of and how you can train to get results.


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