Hypertrophy - The Science of getting BIG (part 1)

In this part 1 of hypertrophy, I will focus on the physiology and anatomy of how and why our muscles grow through training. In parts 2 and 3, I will focus on the training needed for maximum hypertrophy and the nutritional demands and supplementation.

There are two ways that a muscle can grow and increase in its cross-sectional area (CSA). The increase in whole muscle CSA is primarily attributed to an increase in individual muscle fiber CSA. The other way of increasing muscle CSA is fiber hyperplasia, or the increase in number of muscle fibers within a certain muscle. This is still an ongoing debate within the topic of muscle hypertrophy (the fiber hyperplasia that is).

Individual fiber hypertrophy is a result an increase of protein synthesis (creation or building of more). Protein synthesis is always changing but the rate at which it changes is a result of the net gains of protein synthesis and protein degradation. Resistance training results in a net protein synthesis (Synthesis > Degradation).

During the exercise, degradation is higher than synthesis, but after exercise, during recovery, the synthesis increases and a net protein gain is the result. So adequate recovery is vital in gaining muscle mass (see article on exerQ – Strength training and recovery times). It involves an increase of contractile proteins actin and myosin (within myofibrils) and an increase in the myofibrils themselves. Other proteins such as structural proteins titin and nebulin for example also increase proportionally. A 2002 study by Roth et al. showed than resistance training alters up to 70 genes that almost all result in up regulation of muscle growth and down regulation of growth inhibitory factors.

Fiber hyperplasia has been shown to occur in animals but there is limited research and evidence that it occurs in humans. It has been shown to occur in animals under very high intensity resistance training. It has been shown that well trained athletes possess more fibers than untrained but it is uncertain whether or not it is to do with natural genetics or induced changes from training. Hyperplasia therefore cannot be thought of as a major contributor to muscle hypertrophy as there is little evidence of it in humans and if there is, it only contributes to > 10% of total hypertrophy.

So overall, individual muscle fiber hypertrophy and an increase in fiber CSA is the main reason for muscle mass increases following correct hypertrophy training periods.

JJ

check out these books
Essentials of strength training and conditioning 3rd edition - Baechle and Earle
Physiology of sport and exercise 4th edition - Wilmore, Costill, Kenney

Astronauts and Exercise in Space: New Developments

Astronauts in space can spend hours exercising everyday. This aims to counteract the detraining effect of zero gravity conditions, which cause numerous physiological changes in the body. In muscle tissue, mass and strength decrease over time. The strength loss is especially evident in the muscles used to maintain posture, as they become largely irrelevant whilst floating around a spacecraft. Another significant effect of weightlessness is a decline is the density of bone, about 2% per month on average in space. This is less reversible compared to muscular changes and can have a particularly debilitating impact on return to earth.

Cardiovascular changes include increased blood return to the heart, due to less gravity-induced pooling of blood in the legs, while the “puffy faces” of astronauts develop due to this redistribution of blood in the body. Decrease in overall blood volume also develops and can cause low blood pressure and fainting when back in normal gravity environments. Many of the changes contribute to an overall drop in maximal aerobic capacity/fitness (VO2 Max). These negative adaptations to out-of-orbit travel have generated more and more research in designing relevant exercise programs and equipment, which seeks to safeguard the future health of astronauts.

Many different types of exercise and training have been used, some proving more effective than others. Heavy “push-pull” equipment attached to the spaceship, elastic bands/cords/belts and resistive equipment have been developed, while “strap-down” treadmills and bicycles are the norm. One device, currently in use, is the advanced Resistive Exercise Device (aRED). This works with vacuum cylinders, similar to bicycle pumps in reverse, which can apply loads up to 250 kg, according to NASA. In the example of a squat, the vacuum engages as the astronaut stands up, and when squatting back down, the vacuum draws the bar back to the origin position. The main concern, even with creating beneficial weight-bearing or elastic equipment, is still a lack of a total unilateral force acting on the body such as gravity. This leaves the decreases in bone density largely unaffected.

Latest research mainly revolves around creating artificial gravity-like forces. One design, dubbed “The Space Cycle” by researchers at the National Space Biomedical Research Institute (NSBRI), aims to accomplish this while aiming to be small enough and simple enough to operate and/or repair in a spacecraft. Picture a two-person, hanging merry-go-round. A rotating wheel sits on top of a central column. On one side of the wheel a reclining bicycle is suspended. Opposite is a cage-like platform, where a second person will stand. As the one astronaut pedals the bicycle, the whole apparatus starts to spin, causing both the bicycle and the platform to rotate around the column. As the rotational speed increases, both astronauts begin to experience effects of this centrifugal force as a form of artificial gravity.

Astronauts on long-term missions presently need approximately two hours of standard exercise a day to resist the effects of micro-gravity. The Space Cycle is seen as a way of reducing this exercise time, therefore increasing the productivity of those onboard. The weight of the mechanism, which is currently constructed out of steel, poses a problem. This may be reduced in the future using carbon composite materials, which may also slightly reduce its diameter, making it possible for use on the International Space Station.

Jed

Gene Doping: From The Inside Out

Defined by the World Anti-Doping Agency as “the non-therapeutic use of cells, genes, genetic elements, or of the modulation (adjusting) of gene expression, having the capacity to improve athletic performance", this relatively new form of performance enhancement is possibly going to turn doping on it’s head, while pushing ethics and morality in sport and the sport industry to the fore.

First of all, what is a Gene?
Inside human cells, genes provide a sort of “blueprint” or instruction for protein production. Genes are made up of chains or arrangements of DNA. This determines how the cell will function and also its physical attributes.

Gene doping developed out of the concept of gene therapy; treatment developed to cure or ease genetic diseases and disorders such as muscular dystrophy or sickle-cell anaemia. Damaged or flawed genes are replaced with modified, functional ones. These same techniques that can help ordinary people stay healthier could be used to create “superathletes”; weightlifters who “naturally” have larger thigh muscles, cyclists who have more aerobic/type 1 muscle fibers or higher aerobic enzymes produced in those muscles.

Changes in the expression of genes is not a new concept in the science of the human body. Many ordinary medicines can have this effect, as well as daily activities. Training and exercise at least partly modify the expression of one’s genes. But it’s this possibly permanent baseline transformation of the building blocks of the athlete’s body using technology that could be the next big illegal thing. (And possibly is already...). Universities of Washington and Florida were able to give trichromatic vision to squirrel monkeys (naturally dichromatic, using only two primary colours) using gene therapy, possibly leading to a treatment for colour blindness in humans in the future. Higher endurance and increase in musculature in “marathon mice” arose when a group of scientists studied three proteins controlled by a gene that influence how the body manages fats and sugars. This type of research eventually turned towards athletic performance.

How does gene doping work?
Usually a performance-enhancing gene is injected into an athlete carried in a harmless/damaged virus or bacteria (a vector; vehicle to transfer foreign genetic material into another cell). These synthetic genes now in the cells result in altered production of proteins/chemicals and cell function, continuing long-term in most cases.

One of the first gene therapy products associated with genetic doping appeared on the eve of the Turin 2006 Olympic Winter Games, where Repoxygen emerged as a possible substance in use at the Games. This medication was initially considered as a way to fight anaemia.

Detection can prove very difficult. The synthetic genes used most likely appear identical to the natural genes. Identifying the vector or particles of it is possible, but only through muscle biopsies (procedure in which a piece of muscle tissue is removed and examined microscopically). This is not ideal for athlete as some damage, swelling and weakness for a short time results. Genetic “bar codes” or markers can be produced by manufacturers/scientists for their therapeutic products, but this would require input from all relevant parties and administrators. Patterns of protein production and protein levels can also sometimes be analysed. The World Anti-Doping Authority is currently working on a test to check the expression of all 25,000 of the human body's genes, which will look for abnormal patterns.

There are many dangers and possible side effects of gene doping. Often a single gene will have more than one effect in the body and over time illicit other unwanted responses from the body. As with most substances, people’s bodies respond differently and their immune systems especially so. What looked like a successful bid to cure a severe immuno-deficiency disorder, the so-called bubble-baby syndrome, was stopped when some of the children in a French study developed leukaemia, which proved unexplainable. Increased risk of cancer is often a result of the change in DNA within cells. Some hereditary genes might become altered which will then affect children born to athletes. (Interesting thought: If those children grow up to be athletes, would they then also be identified and banned from competition...?)

The ethical issues raised are ever increasing. Cheating is taken to a whole new level. Are we getting closer and closer to playing God? With regards to the uncertainty of long-term effects, who’s to blame when things go wrong? Not only the athlete, but the sports community and society as a whole, will be harmed. Overall, the uniqueness and variety of sport would be removed.

BELGIAN BLUE BULL demonstrates the effect of blocking the antigrowth factor myostatin. A natural genetic mutation in this breed produces a truncated, ineffective form of myostatin, which allows muscle growth to go unchecked. The absence of myostatin also interferes with fat deposition, making these “double-muscled” cattle exceptionally lean.

Here's a really interesting case of when things go wrong:
http://en.wikipedia.org/wiki/Jesse_Gelsinger

Jed