By Elena Voropay

In any sound system, the quality of the sound ultimately depends on the speakers. In muscular system, it depends on its carriers. If you are a proud owner of embellished body cuts or would like to become one, may I suggest you express some respect to the lightning-paced muscle growth and find what makes the canyons so brawny. There are a few extremely interesting mechanisms involved.

Anyone who performed some form of resistance training probably had the balmy dream of getting bigger and stronger. It usually doesn't take long to grasp the nature's tricky rule of never letting the body to be a record-breaker. Human body is adjustable to almost any environment, but the mechanism of change is slow. Muscles in particular are just plain lazy. Even if you place them under horrific loads, they will only develop enough mass and strength to deal with the loads placed upon the lean tanks, but it will take a long time. When it comes to gaining size, your guns of steel are even more rebellious – at a certain point they reach a plato and refuse to grow.

Walk into any gym, talk to a few gym rats talk about getting bigger for a few minutes and in an hour or so  you may feel like a walking encyclopaedia full of facts about muscle growth. Tips, tricks and techniques of what you should do to cultivate new lean tissues blossom every day. Unfortunately, even the most knowledgeable experienced recreational bodybuilders don't really have a clue as to how or why muscles actually grow.

I have heard of little muscle fairies which hide inside gym lockers, sneak into bodybuilders' bags and water bottles, and then come alive in their rooms at night. These fairies bring the magic of muscle growth into reality. And when the bodybuilders wake up next morning after hazardous training last night, viola - they're bigger. So, your main goal is to go to the gym, otherwise your friends' will steal the mighty power of muscle-building fairies.

Jokes aside, most trainees know the obvious – consistent hard planned workouts, heavy weights, lots of protein and carbs, buckets of supplements all build the mighty frame. It's all for the good, at least it makes us think that we know a lot about the how to get big. However, the story of muscle development explanation is only in its infancy stage, and there are a few myths surrounding the harvest of your gym hours. Not everyone knows or even wants to explore about what actually happens inside the muscles when the bodybuilding fairies do their magic at night. I know you are not one of those people and are ready to get your hands dirty digging deep inside the marvellous lean structures.

Warning: If you want to develop more muscle, then you better gear up to sweat some hefty weights and be prepared for extremely slow and painful gains. Frustrating, I know, but the journey to the final destination is a trip of a lifetime which, believe me, you don't want to end.

How do you grow your muscles? In textbooks you may read that muscle growth occurs whenever the rate of muscle protein synthesis is greater than the rate of muscle protein breakdown. In other words, when anabolism overrules catabolism. Obviously, good training, nutrition and rest are involved in the synthesis and breakdown of proteins which are controlled by complimentary cellular mechanisms. So, you train and induce catabolism breaking down muscle fibres. You eat and rest afterwards to provide environment for anabolic growth. Seems common sense by now. But the question remains: How and why specifically does a muscle’s size increase?

To really find the answer to your question I encourage you to jump on a time machine and take a journey a few years back. Remember when you got out of your mom's belly? I hope not. But what your conscious mind doesn't remember is programmed in your physical body. Back when you still were an embryo, your muscle cells received an important message of future growth and started developing from spindle-shaped embryonic cells called myoblasts - the super "powerhouse" cells. These naturally come from the human body's muscle stem cells which dare to be different.

Their biology is not as complicated as it sounds. You have probably heard of stem cells. Everybody has them. Stem cells are general, non-specific (undifferentiated) cells that can transform into any cell in the body. Liver, skin, retina, muscle – they're all possible cell types that can be created by stem cells.

These stem cells have a different name and are named Satellite cells in skeletal muscle tissue. Another term, another anatomical jargon for no reason other than to confuse you and train your memory. Ok, this is not exactly true, but at the end you need to know that these under-appreciated cells actually exist and can help you grow. These cells are termed Satellite cells because they are located on the outer surface of the muscle fiber, in between the sarcolemma and basal lamina (uppermost layer of the basement membrane) of the muscle fiber. Most of the Satellite cell volume is occupied by one nucleus.

You came out as a tiny offspring with not much bulk on the fragile under-developed bones. Day after day, year after year, your chintzy physique expanded into an attractive unique muscle-carrying mountain – your muscles, and all other tissues for that matter, clinged together into a well-suited body. What has happened and continues to this day is worthy of anyone's attention. When myoblasts fuse together, they become muscle fibers with multiple nuclei and have the ability to take on the properties of other cells. In fact, they can actually regenerate and repair themselves. For example, if you injured a leg muscle, the previously undeveloped muscle cells, the myoblasts, can grow into fully developed cells and make up for the tissue.

Satellite cells were identified over 40 years ago through electron microscopy. At this point in time, it is widely believed that Satellite cells are the committed stem cells of adult skeletal muscle. Now there is a lot of controversy about the theories that try to explain the exact mechanism of muscle growth. Most support the notion that the muscle fibre does not dot divide, thus you can't grow new muscles cells after you become an adult.

Then, what happens to all the athletes and bodybuilders you triple their muscular size way after growing up? Easy. They take steroids. At least some of them do. But this is not the complete truth and you don't need drugs to grow. With proper training, nutrition, recovery and possible harmless supplementation your system will expand around the clock. How and why this happens is a heating debate that's been going on for decades.

Previous notion was that you keep your genetically or prenatally determined number of muscle fibers, but they can get a lot thicker and denser, thus the size of existing individual fibers grows, which most of us know as muscle fiber Hypertrophy. Another more recent theory suggests that enlargement takes place due to the increase in the number of muscle fibers and is commonly referred to muscle fiber Hyperplasia.

Both of these mechanisms happen in response to extreme conditions. What conditions we are talking about? In unhealthy environment, it can be due to immunological or hormonal disorders. For example, burn victims can possibly grow new skin, hair, muscles if there is enough support in the body. Corns, calluses, goiters also grow and multiply. In the healthy environment of exercise, excessive overloading the muscle with resistance stimulates it to become larger, so training is a given thing. But for this to fully occur, you need to employ other supporting factors which increase muscle cells’ thickness and number.

The first theory of muscle growth is Hypertrophy which means 'excessive growth.' Essentially, it is an increase in the size of existing cells or fibers rather than an increased number of cells. In other words, under certain circumstances your muscle cells enlarge in size beyond their current state of being.

There are two types of Hypertrophy: Transient and Chronic. With the former, you increase the volume contained within the muscle cell. Otherwise, your option is to upgrade the actual amount of muscle contractile proteins making up the muscle cells, which happens with later.

To give a simple analogy to help differentiate between the two types of Hypertrophy imagine your muscle cell as a water-filled balloon. To make the balloon bigger, you can either add more water to the balloon, thereby stretching it to its maximum capacity and increase cell volume as in Transient Hypertrophy. Otherwise, you could theoretically add more "rubber'” to the balloon material to make the overall size of the balloon larger and thicker as in Chronic Hypertrophy. Although the mechanisms that cause increased cell volume and increased contractile protein content may be different, both are affected by weight training or repetitive resistance force.

The very first type of Hypertrophy, known as Sarcoplasmic Hypertrophy is the very famous “pump” you feel in muscle tissues after an intense workout. This is simply called edema and it is caused by the transfer of blood plasma into the muscle tissue which create Transient or short-term Hypertrophy. This phenomenal change is the result of fluid accumulation, or oedema, that is lost from the blood plasma and lasts only for a short time. When athletes and bodybuilders talk about an infamous “muscle pump” after a sprint, a few plyometric jumps, or one really good tailored muscle-building exercise set, they are talking about Transient Hypertrophy.  The visible changes are almost immediate because the volume of sarcoplasmic fluid inside the cell and also the fluid between the actual cells will go up. If the muscles are the baloon, then you are filling them with water - hence, the “pump”.

There are different ways which may contribute to this pumping hyper-hydration effect. First, it comes from the specific training. When you work your muscles using high repetition range and high volume of training, the tissues take up most of the blood and fluids and all the nutrients found in blood and plasma travel to the body part in need. The sheer loads of resistance lead to increases in the cellular storage of substrates such as carbohydrates, lipids, or amino acids, as well as increases in the cellular movement of ions like sodium and potassium.

 
Basically anywhere between 13 – 25 reps per set would be classified as high reps which make some amazing pumps. Many trainees who work out this way are convinced their muscles are getting bigger. They go as far as saying that unless they“feel” the growth, the pain, the swelling inside the lean tissues, there is no point in training at all. If they are not getting the pump - they are not training hard enough.

If they are hitting anything at the gym while working out with light weights pumping out high reps, then it surely is not their anabolic flux. Maybe these guys go to the gym for anything but getting big and strong – socialising, being part of the “man crowd” or they have read too many fitness tips from girlish mags. I know what they are trying to hit - must be that cute blonde on the elliptical, or the redhead who spends two hours in the bent-over position with her butt way up in the yoga class. For these dude the gym is just another substitute fo the local pub or bar.

By now you are probably wondering – what is happening inside the muscles that makes them visually bigger so quickly? Common sense tells that if you increase the volume and number of repetitions something should grow. That something is the number of mitochondria, intracellular bodies in the cells. Your muscles will also increase the concentrations of the enzymes involved in burning fat – the process known as the oxidative phosphorylation. What's more, other mechanism of energy production, the anaerobic glycolysis, will get a stimuli to become more efficient.  

How important is a 'pump'?

"Having a pump is like having sex. I train two, sometimes three times a day. Each time I get a pump. It's great. I feel like I'm coming all day" (Arnold Schwarzenegger).

Getting a “pump” doesn't have to do much with long-term strength or size. It is not a prerequisite nor a necessity for building muscle. Tthink about it – how much weight would you be able to lift for 25 reps? Not much, a lot less that what you would use in the 8-rep max. There is no possibility whatsoever that a weight in the hig-rep range is simply heavy enough to force the muscle to continually adapt and grow.

If you see the guy working out for “pump”, he is pretty much wasting his time, using up the valuable energy he could use for real muscle-building using heavier weights and burning more calories. Ask the dude about slowing down, and you will get an angry response something along the lines of minding your own business, or body in this instance. Poor fellow, maybe if he hasn't trained this “hard”, he could've grown in size, progress in speed, build more strength in half the time. If fact, I can almost guarantee that this over-hyped “pumping” is what brings muscle growth to hault.

Repetitions is complicated subject.

Their number depends on what you are trying to achieve.
You can say that I am not a big fan of 'pumps' or high reps on most exercises, but there are actually times when high reps can be quite beneficial.

The very first scenario is the beginner who hasn't really worked out, who doesn't know what true bodybuilding sweat is. We've all been there at some point and Jay Cutler or Dexter Jaxon were not born with the Hack-Squat Machine glued to their legs. If you don't have the strength, coordination or stabilization to maintain perfect form and find it difficult to use a great deal of weight for more than eight reps on any given exercise, you can start with lighter loads and higher reps. Eventually, as you will develop the neural patterns and other metabolic machinery, you can increase the intensity by stripping down reps and adding plates.

When you are more advanced and have developed a respectable level of strength, high reps can also  be a great tool for stimulating new muscle growth. If you add the filling of high-rep training into your muscle-building sandwich, it can and will help you grow. High-rep training has profound effects on increasing strength-endurance or the ability to do reps with a certain weight because it dramatically increases the muscles' ability to produce ATP, the source of energy for all muscular contraction - Type II fibers included.  In addition, when higher reps are performed substrates such as phosphate and hydrogen ions build up in the muscles. There is speculation from some researchers who theorize that the presence of these substrates may further facilitate the muscle growth process. There are other intracellular bodies whose growth and/or proliferation would fall under the category of Sarcoplasmic hypertrophy. These would be organelles such as the ribosomes, which are involved in protein synthesis, but they would have little direct impact on overall muscle size.

You increase the fluid volume of the tissue that supplies energy to the muscle, but it represents only around 20% of the total muscle cell volume in untrained individuals. Only 20%!!! What about the remaining 80% where the majority of growth potential lies? It comes from two other paths of muscle growth - Sarcomere Hypertrophy and Hyperplasia.

Challenging muscles with weights you can lift for more than 15 repetitions is likely to simply tone up and shape your muscles without much increase in size. Good for beach looks ladies dig. May help somewhat with caloric nuke, fat burn and emphasize developing muscular endurance, but for developing size you need loads. Heavy loads. This is a fitness fact.

Other techniques where the loads reach 90% of 1RM are performed for under 6 repetions may also produce Sarcoplasmic Hypertrophy. Good examples are Plyometrics and ballistic Type dynamic movements, sprints and Super-fast repetitions.

So, both very high and very low repetitions give you Sarcoplasmic Hypertrophy, but this Type of Hypertrophy doesn't make you stronger or larger overall. While stronger muscles can handle heavier weights and lifting heavy is the most important factor necessary for muscle growth, you should aim to balance your training using various weights. At the end, don't you ever let the perception of 'pump' be your guide - regardless if you are experiencing the sensation or not, stay focused and concentrated on the muscles you are training and remember to maintain a strict form while doing your exercises.

There are other variables that effect how much 'pump' you feel after the workout. For one, consider your diet – if you are not eating enough carbohydrates, for weight loss reasons for example, you can exhaust your muscles with training, but may not get the same 'pumped-up' sensation as if you had enough sugar in your system. This is because each gram of carbohydrate holds on to 3 grams of water, so there is more fluid in the muscles.

If you are dehydrated, the body will hold on to every last drop of water, perceiving the low water levels as a famine. Here, the water will travel from muscle cells and become stored under the skin, showing up in the form of swollen feet, hands and ankles, as well as puffed eyes. Only after proper hydration the body will start releasing the stored water. The need for water increases when you exercise. As you bring your heart rate up and increase metabolism, more water is lost through increased rates of perspiration and respiration. As we know now, decreased body water and intracellular nutrients can lead to cell shrinking and increased muscle protein breakdown. This is accompanied by a decrease in blood volume, reduced ability to get rid of excess heat, thus leading to possible heat exhaustion or even heat stroke.

If you are only 2% short of water in your system, your aerobic and anaerobic capacity dips bringing physical and mental performance down by 20 %. Research shows that dehydrated people perform worse on arithmetic tests than well-hydrated ones. Water essentially acts as a means of healing by encouraging the immune system to work overtime without fatigue, activating important chemicals that stimulate germ-killing cells.  

The second way you may be able to maintain the 'swelling' is from specific nutrients. Research has shown that supplements like Creatine, Glutamine, and simple sugar Ribose lead to increases in cell volume by both increasing their own content within the cell and by attracting water into the cell. Not only this is good for the size, the properties of these supplements accentuate hydration within the muscle and improve nutrient delivery.  Supplementing also leads to better internal muscle hydration and 'pumps up' your beef – the other side of having a flat feeling in your muscles.

When fluid moves into the cell, it causes it to stretch and enlarges the look of your muscles. Unfortunately, such increases in cell volume and blood flow disappear almost as fast as they come to life. Transient Hypertrophy comes on fast, bloats your muscle cells and goes away as quickly. It lasts anywhere from a few minutes to several hours after the exercise. A single bout of exercise stimulates protein synthesis and fluid retention within 2-4 hours after the workout which may remain elevated for up to 24 hours.  So, you can see enlargement in your muscular tissues for up to a day or two after your workout spirit said “enough”.

You can stay pumped-up for now with Transient Hypertrophy for a couple of days, but a better way to enlarge your muscles is through Chronic muscle growth. The difference between Transcient and Chronic Hypertrophy is that the longer it takes to make it happen, the longer the change stays within the tissue. It may take as long as several weeks or months for any visible changes to the muscle to become evident.

Hypertrophy is a balancing act between anabolism and catabolism. Fortunately, there is nothing mystical about this balance or the training style. Unlike the “pump” or the Sarcoplasmic Hypertrophy, in Sarcomere Hypertrophy we need to focus on increasing muscle tension. The higher the residual tension in a muscle, the higher the muscle tone in that muscle. Lifting heavy weights generates higher tension in the muscle than lifting light weights.  This popular style of training will likely produce Hypertrophy as suggested by the research. If you want to grow bigger muscles you must train your muscles against a resistance great enough to stimulate Hypertrophy, but not so great that you cannot continue the set long enough to stimulate growth.

When we talk about Hypertrophy, we are most often referring to Chronic growth. This type of Hypertrophy is the most lasting way to ensure that muscles enlarge and stay enlarged. Chronic Hypertrophy is the consequence of long-term training which actually changes the structure of the muscle. This phenomenon of muscle growth is head and shoulders above the short-lived Transient kind. Only Chronic Hypertrophy has the ability to remodel the muscle fibre permanently building bigger and stronger tissues than before.

The impressively large and muscular physiques of bodybuilders, weightlifters, power-lifters and gymnasts may tend to create the impression that their shape is due to the same sort of Chronic muscle Hypertrophy. However, research by Russian scientists (Nikituk & Samoilov), has shown that not all Chronic muscle Hypertrophy is essentially the same. There are at least two different types of muscle Hypertrophy: Sarcomere Hypertrophy and Sarcoplasmic Hypertrophy.

Sarcomere Hypertrophy is associated with growth of the contractile components of the muscle fibers (the actin and myosin complex) and happens due to growth of the structures supporting and surrounding the contractile elements (the Sarcoplasmic Reticulum and Sarcoplasm). With Chronic Sarcomere Hypertrophy your muscles actually grow like weed after the rain and respond by increasing the cross sectional area through making up more of contractile proteins within the muscle fibre. This is how you add to the basic contractile package of your muscles, the Sarcomeres. The more fibers available to contract, the more weight can be lifted! This is, of course, if you train, eat and rest fully.

Determining whether you're doing it right is easy.

Three to eight sets, 6-12 reps, 20 or more sets per body part is advocated here. From all sorts of ranges targeted for muscle Hypertrophy, there is indeed an optimum sweet spot -  6 to 12 reps per set (smaller muscle groups may respond better to even higher reps) is the ‘Anabolic Rep Range.’ Select weights that allow you to complete good clean repetitions without sacrifising the technique.

Most people will use between 70% and 85% of their 1-rep maximums to achieve this. Training in this range produces micro-trauma to the muscle fibers that results in muscle growth, provided you rest well and eat plenty.

If your body knows weights for years, then you should train with all the weight you can handle for 6 - 8  reps at max. Use the weight that you can honestly pump out some good, clean reps with strict form for no more than 8. If you can push or pull 9 reps without unloading, make the last rep a Super-Slow one to reach complete failure. If this weight gets too easy, it is about time to increase the weight.

Can you use “heavy” weights for high reps? Yep, in fact most times it works out better than using heavier weights. The concept only applies for a few muscle groups and exercises and shouldn't be used all the time.

The exception to the rule of low repetions are abs and legs.

One of the reasons is found in the muscle fibre composition of the legs. Humans are made for walking, running and moving from one place to another using our quads, hamstrings, gastrocnemius and soleus of the calves, hip adductors and abductors and, not to forget, our ass muscles which come next to the core, abs included. All these lean tissues are predominantly composed of endurance-Type Slow-Twitch muscle fibres which are used in high-rep training. So, by focusing on improving the status-quo of your body from the waist down will improve your movement patterns and muscle efficiency. Plus, research has shown that both high and low reps also target Fast-Twitch strength and power fibres.

Compound lower body exercises such as squats are phenomenal muscle builders when done for high reps with heavy weights. For example, on leg days do one or two heavy sets of 4-8 reps on some kind of squat followed by a brutally hard high-rep set of 15-30 reps. Some advanced professionals swear by a finishing set of 100 reps which burns their legs like hell. If your legs don't grow from that, they never will grow from anything. Again, you should be fairly advanced before you start trying high rep killer-sets.

For abs, stay within an 8-16 reps per set for growth. Focus on good form, perform each repetition quite slowly and also hold the movement at the top for a second. There is just no way you could get good form with weights that were too heavy. That’s it. Don’t sacrifice form for weight. Good bodybuilders feel the muscle, not the weight.Also, the high rep set should always follow a heavy set or two. Therefore you would do one or two sets of 5-8 reps first and then follow it up with a set of 15-20.

If you always train for Hypertrophy, you'll probably never gain all the strength or size you could - unless you're a mutant, or on steroids, or both. If you need some sheer bulk for superiority and functional strength, as most bodybuilders and gym-goes do, you can rely largely on bodybuilding methods. Many strength-power and endurance athletes fully enjoy bodybuilding as a form of supplementary training for other sports. Growing new muscle fibres via Hyperplasia means you need to keep your workouts intense, short in time and train hard, very hard.

The word Hyperplasia comes from the Latin plasia, meaning “growth”. The dictionary describes it as a “non-tumorous increase in the number of cells in an organ or tissue with consequent enlargement of the affected part.” In elemental terms, Hyperplasia is the growth of an organ due to an increase in the number of cells. All tissues, including fat or adipose and muscle tissue are theorised to growth through Hyperplasia. Through this cellular development the body grows corns, calluses and goiters. Experts agree that Hyperplasia does happen in smooth muscles like the intestines of humans, and the common belief has been that Hyperplasia is only possible in very abnormal circumstances.

Since most of us, I assume, are not interested in growing tumours or fat cells, let's talk about growth of new muscle cells and their development into new muscle fibers. To be more exact, we are discussing myofibril (muscle fibre) Hyperplasia. Because Hyperplasia means the increase in the number of a cell type, it should occur as the result of splitting of muscle fibers. But we know that overall, each muscle cell has only one nucleus, one core, and doesn't divide, since fully formed it has given up any strictly cellular organisation by the time you became an adult.

While we are born with a pre-determined number of muscle cells, certain studies have shown that not all muscle cells fully develop into myofibrils. It is estimated that about 5-10 % of the cells remain as undifferentiated cells called Satellite cells. This is where the theory of Hyperplasia comes in. It says that these Satellite cells, when given the proper stimulation, can turn into full-fledged muscle fibers—hence, new muscle.

Muscle-splitting has actually been observed for well over a century. Back in 1866 in Germany, scientists Eulenberg and Cohnheim found that animal muscle fibers were capable of splitting if sufficient stress was applied. In humans, fiber-splitting was noted by W.H. Erb back in 1891 who found evidence of Hyperplasia in people afflicted with muscular dystrophy. Durante in 1902, observed fiber-splitting in the abdominal muscles of a pregnant woman.

So, let's say you worked out. You destroyed some of your muscle fibers, which by the way can be done with resistance or endurance training, as well as stretching. This injury is ideal for bodybuilding - it facilitates both growth and increase of the size muscle cells (muscle Hypertrophy) and/or proliferation or growth of muscle cells (muscle Hyperplasia). Usually Satellite cells are dormant, but they become activated when the muscle fiber receives any form of colossal trauma, damage or injury. The workout disruption to muscle cell organelles activates Satellite cells. These proliferate to the injury site in order to repair or replace impaired muscle fibers, then fuse together and to the muscles fibers, often leading to increases in muscle fiber cross-sectional area or Hyperplasia.

Scientists say that there are two types of Hyperplasia:

Sarcoplasmic Hyperplasia which involves an increase in the number of Sarcoplasmic organelles or under-developed muscle cells.

Myofibrillar-mitochondrial Hyperplasia which involves increase in the number of muscle fibres or myofibrils and mitochondria, the energy-producing molecule.

While the complete physiology of muscle growth is still covered with smog, studies performed on animals and birds provide a clue. Bodybuilding cats, for example, have grown their lean mass through Hyperplasia. Ok, we know that there no bodybuilding cats in reality. This is why the experimental household animals were trained to move a heavy weight with their paw in order to get food.

It happened in 1978 when Dr. Gonyea using a Skinnerian behaviour modification technique known as "operant conditioning", transformed ordinary cats into devoted weightlifters. Gonyea attached weights to his cats' paws then required them to press levers to obtain food. This wasn't done to prove the point that pets would do anything for food, but if the alternative to training is dying from starvation, then any living creature could've become a world-class strength champion. So, to get food cats had to lift their weighted paws. Since it was known that the body has the ability to adapt to given resistance, Dr. Gynyea used a specific method to stimulate muscle growth in cats. He gradually increased the amount of weight attached to the cats' limbs which proved again that progressive resistance wins any stagnation.

This study wasn't done just to show that muscle growth is real, but to show that lean tissues get thicker and bigger by other means than Hypertrophy, or enlargement of muscle cells. By attaching weights to his cats paws Dr. Gonyea was attempting to produce Hyperplasia which eventually happened. He reported that cats had a 19.3-20.5% increase in the number of muscle fibers. So, cats actually activated Satellite cells and have grown new lean tissues bigger and stronger.

These outcomes were groundbreaking and some scientists disputed the method Gonyea used to determine the number of new fibers and considered the experiment invalid to concur that the same Hyperplasia is possible in humans. It is understandable because cats have as many as eleven different types of muscle fibers while humans use mostly only three types and have no more than five.

In contrast, other studies on chickens, rats and mice have found that resistance overload resulted in muscle Hypertrophy only - their muscle cells grew in size, but not in number. The interpretation comes quite frustrating at first, but the muscle-growing tunnel has a guiding light – the loading connection. The differences in results between the cat and other animal studies may be a result of the overload used. The cats were exposed to high resistance and low repetitions as opposed to more endurance-type activity used in the other studies. From these and many other studies we can make a preliminary conclusion – to stimulate Hyperplasia you need to double up your iron stacks, but this is not the end of story.

A further study performed on birds reported an increase in the number of muscle fibres in the wing in response to chronic stretching of the muscle by attaching a weight to it. So, in addition to intense training, there is a possibility that intense stretching may also promote Satellite cells to mature. By overloading your muscles, bones and connective tissues with repetitive contractions against resistance and elongating these tissues you stimulate them to adapt in order to be able to produce force.

While animal studies seem to be well aligned, the research on humans is not as clear-cut. The problem with us, two-legged smart creatures, is that not too many want to live in lab cages under experimental conditions for a long time and we all are so different. Our muscle composition is more diverse, as some people have predominately endurance-type or red muscle fibres which are not much of a use in heavy lifting. Then, some may have and use their upper body muscles more often than their legs, or visa versa, and/or have already achieved maximum Hypertrophy at these places. If we place these same muscles under extraordinary pressure of heavy resistance for a while, the lean tissues would have no other choice than to activate Satellite cells as the limit for muscle cell enlargement has been reached. Then, who wants to count all muscle cells under the microscope and compare the “before” and “after” numbers in each person to prove that muscle Hyperplasia is possible?

Well, believe it or not, some scientists went crazy to do just that. Thanks to them, we have evidence to indicate that Hyperplasia may be a real phenomenon in intensively trained bodybuilders, swimmers and other athletes.

In 1982 scientists Tesch and Larsson reported persuasive evidence that Hyperplasia is indeed possible in humans. The researchers tested three groups of subjects: competitive bodybuilders, power-lifters and ordinary untrained physical education students. Performing minimally invasive fine-needle biopsies on all three groups, the outcome was nothing short of new discovery. Surprising finding has given an edge into how and why muscles get bigger. To be precise, how the subjects trained dictated the pathway through which the lean tissues have grown. From the study it was determined that the world-class bodybuilders showed smaller muscle fibers than the power-lifters Even more surprising, muscle fibers of bodybuilders were no thicker than the physical education students' who  knew as much about weight training as you know about ballet or sewing. In other words, the actual muscle fibres did not grow in size from training, but their number increased. Similar study was repeated in 1986 to confirm the finding, with the same result. Their conclusion was that the increased muscle size of the bodybuilders was likely the result of fiber-splitting (Hyperplasia) rather than Hypertrophy.

Another longitudinal study followed a group of recreational bodybuilders for 12 weeks. The results showed that the number of muscle fibers in the biceps brachii muscles increased significantly when the training was intensified. Unfortunately, this didn't happen for everyone in the same way which suggests that if Hyperplasia is possible in humans it may only occur in a few individuals under certain conditions. So, we need to factor in all specifics of individual muscle physiology and training history.

Muscle growth comes painfully slow, no doubt about it and Hyperplasia is not a breeze - you must train very intensely and stretch your muscles for other reasons than prevention of injuries for several years to notice minuscular results in structural changes.

There may be a notable exception, however. If training is started while you are still in the growing stage—for example, a teenager—then Hyperplasia is more likely to happen. At youth, you have a better potential for growth – hormonal surge. Some scientists believe that growth hormone, which is at its peak during adolescence, combined with high-intensity exercise, is capable of stimulating muscle Hyperplasia.