Understanding the Science of Bodybuilding will help you to understand everything else that follows, and will enable to you to make your own changes and know what will work and what won’t. Fortunately the fundamentals are fairly simple. There are many scientific words involved in the Science of Bodybuilding but we will try to keep them to a minimum.
Skeletal muscle tissue is the largest organ in the human body accounting for more than a third of our body mass. Like every other part of the body, muscle tissue is formed from trillions of tiny cells which in muscles are sensibly named ‘muscle fibres’.
Unlike other cells however, muscle fibres have multiple nuclei (the command centres of a cell) meaning they cannot multiply through mitosis (cell division) as they are too complicated. This means we cannot enlarge our muscles by increasing the number of fibres, but instead must increase their thickness.
Muscle fibres themselves are composed of smaller ‘strands’ named myofibrils, and in turn myofibrils are made of sarcomeres. Inside Sarcomeres are even smaller filaments made from the amino acids myosin and actin (it’s a bit like a Russian doll). Now when a muscle contracts, this is an effect of the myosin ‘pedalling’ along the actin, so pulling the sarcomeres inwards like collapsible tubes.
As they do this in great enough numbers it becomes visible on a macroscopic level (meaning you can see it) and the muscle contracts, pulling against your tendons to move your joints.
Following so far?
Then you’re doing better than I am… Just to complicate matters further there are actually 2 different types of muscle fibre: ‘fast twitch muscle fibres’ and ‘slow twitch muscle fibres’ (also known as type I and type II muscle fibres respectively).
As the names suggest, fast twitch fibres are those used in fast explosive movements such as jumping, sprinting and weightlifting; while the slow twitch fibres are used for endurance events such as long-distance running or rowing.
The difference here is due to the amounts of mitochondria and creatine phosphate among other things in the fibres which basically dictates how quickly/efficiently they get energy from ATP (Adenosine Triphosphate – the energy currency of all life).
Type II muscle fibres can be further divided into Type IIa and Type IIx with the latter being faster. Certain mammals have yet another kind of fibre, ‘Type IIb’ which is used for even more sudden and powerful bursts of energy explaining why they can change direction more suddenly and evade predators. It’s why I can never catch my dog when he gets my slippers.
Confusingly you will sometimes find Type IIb referred to as Type IIx and vice versa, but while most websites and magazines still refer to humans’ fastest fibre as Type IIb most scientific journals and papers have now adopted IIx which is the more modern view.
Generally a bodybuilder will have more Type II fibres, as will sprinters while long distance runners will need more Type I; your muscles reflect your lifestyle. While our ratio of fast-twitch to slow-twitch fibres is largely determined by genetics, recent studies have shown that we may in fact be able to convert one type of muscle fibre into another through training.
So the more you go to the gym the more fast twitch muscle fibres you’ll develop. It’s also possible to develop twitch muscle fibres that are neither type I nor type II, but somewhere in between. The older we get the larger the proportion of muscle fibres that fall into neither category.
Now on to the good bit – muscle growth.
As previously stated, muscle fibres cannot reproduce via mitosis due to their multiple nuclei. What this means is that in order for the muscle to grow, the existing fibres need to become thicker and for this to happen muscle must add more myofibrils, which as it happens can split down their longitudinal axis so growing in number. This action however requires allot of Myosin, Actin and other proteins. The amount of protein that your muscle fibres can use is limited by the number of nuclei for each one.
When you put stress on a muscle from overloading (by picking up a weight) you are simultaneously creating ‘microtears’ in the fibres. Gory though that sounds, this is actually how hypertrophy occurs (hypertrophy meaning muscle growth).
Once the fibre is recognised as damaged you see, nearby stem cells which are currently a hot topic for their ability to adopt the properties of any type of cell called ‘satellite cells’, will be recruited in order to repair the damage. The single nuclei of these satellite cells however will stick around and become incorporated into the repaired fibre meaning that it has more nuclei than it did before, and can use more proteins to become thicker via the splitting of myofibrils.
The amount of stress you can put on your muscles in a single workout however is limited by how much energy you muscles have access to. Energy for muscles comes in the form of ATP (Adenosine Triphosphate) which is made of three nucleotides bound by high energy bonds which when broken release lots of useable energy.
They can obtain this in a variety of ways, with a small amount of ATP (around three seconds worth) being stored within the muscles themselves. Further energy is then produced when the muscles’ stores of creatine phosphate is used to recycle used ATP (ADP and AMP – Adenosine Diphosphate and Adenosine Monophosphate respectively) to produce more ATP.
This is known as the ‘phosphogen system’ and can sustain continued exertion for a further five seconds. This might not seem like a long time, but eight seconds is more than enough to complete a repetition of most exercises. Taking the best testosterone booster supplement is a great help here.
Once the ATP and Creatine in the muscles is depleted, the muscles begin using ATP from glucose which the body can get from it’s stores of glycogen, though this is a slightly slower process. Known as the Glycogen Lactic Acid System, here glycogen stored in the muscles is split into glucose and then again split further to release four ATP molecules.
This provides roughly 1.5 minutes of extra energy on top of the initial 8 seconds, although at lower power and also produces the bi-product lactic acid (hence the name). This method is used in activities such as swimming or the 400 metre sprint and is ‘anaerobic’ meaning it does rely on oxygen.
Finally the Aerobic System is used when the body needs to maintain a steady supply of energy for extended use. It achieves this through the oxidisation of nutrients from food in our mitochondria, here the system will ‘burn’ carbohydrates first, then fats and then finally protein to extract glucose.
This is why bodybuilders should not engage in excessive CV or completely eradicate Carbohydrates from their diet, as they would risk cannibalising their own protein and eventually muscle. In a dramatic improvement over the other systems, the Aerobic system can sustain an athlete for over two hours, with carbon dioxide and water as the only by-products rather than lactic acid (meaning less pain).
In order to provide muscles with the necessary oxygen supplies you will begin breathing more heavily and your body will pump the blood to them (hence the feeling of being ‘pumped’), diverting it from other organs. Oxygen being carried within the haemoglobin in the blood and myoglobin within the muscles.
These three systems kick in that sequence, beginning with the Phosphogen System before moving onto the Glycogen Lactic Acid System and finally the Aerobic System as the body demands it.
And that my friend is an introduction to the Science of Bodybuilding. Please leave a comment below if you have any questions.
Bodybuilding is a very tough work and very time taking process. It requires a lot of hard work and training along with lots and lots of protein rich food every day. They are not allowed to miss any of these mentioned things for a single day of preparing for any competition.