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The Great Genetic Debate

  • 11 min read


by Mike Arnold

There is no sport in the world in which the subject of genetics is given as much time and attention as it is in bodybuilding. Although genetic ability is equally important in many athletic endeavors, it is rarely regarded as the be-all, end-all of competitive success, with factors such as mental disposition and strength of will generally considered the more important of the two. From a young age, most athletes have been instilled with a sense of personal responsibility for their own success. Whether they showcase their talents in the arena, out on the field, or in the ring, they are taught that hard work and dedication are paramount to the achievement of their goals.

While these lessons are to be found in bodybuilding, it is with ever-decreasing frequency that they present themselves, taking a backseat to more corporal determinants. Rather than imparting encouragement to newcomers as they explore their individual potential, we force them to contend with their genetic shortcomings right out of the gate, thereby imposing premature limitations on their development. While it would be foolish to ignore the role of genetics in this sport, making it a focal point before one has had the opportunity to become acquainted with those aspects of their DNA which are not immediately apparent, only succeeds in bringing about discouragement and the increased likelihood of failure.

Arthur Jones, 1970’s entrepreneur and inventor of the Nautilus line of weight training equipment, was one of the first to approach the subject of bodybuilding potential from a scientific standpoint. Using muscle belly length as a means of assessing growth capacity, Jones claimed that it was the single most important factor in building big muscles. Several real-world examples were cited which appeared to lend credibility to this claim, the most notable of which was Sergio Oliva. With muscle insertion points that, at least in some cases, seemed to extend almost beyond the joint, Sergio was the most massively muscled bodybuilder of his day.

The concept behind muscle belly length as it relates to growth capacity is a simple one. The longer the muscle belly is, the greater its potential cross-sectional area and volume. No doubt, Sergio’s extreme genetic gifts in this area made it easier for him to pack on muscle tissue, but to what degree? Although Jones was astute in his observations and correct in theory, he became dogmatic in his beliefs, unwilling to bend or accept the possibility that other genetic factors may allow a BB’r to make up for, at least partially, a lack of genetic gifting in this area. He even went so far as to place limitations on arm size, correlating tendon length with specific arm measurements.

These days the subject is a little more complex, as science has revealed numerous other factors which can have a direct impact on a muscle’s ultimate size. However, while there is certainly a connection between growth potential and bodybuilding potential, they are two entirely different things, as success in competitive bodybuilding is dependent on much more than muscle size alone. Of the various factors involved, we can split them up into two primary categories: internal and external. In other words, those things we can see with our own two eyes and those things which are less obvious, being concealed from view.

Skeletal structure is the most prominent of the external factors, as it is both fully discernible from the get-go and unchangeable, without any hidden characteristics which might skew one’s initial perception. Assuming the individual has fully matured, what you see is what you get. Structure is easily one of the most important factors to bodybuilding success, as it is the foundation on which everything else is built. It plays a big role in determining shoulder width, waist size, and even affects muscle shape, while being solely responsible for limb-torso length ratios. Without the right structure, a bodybuilder will never possess a truly standout X-frame (i.e. Dennis Wolf), billowing muscles tapering down to tiny joints (i.e. Flex Wheeler), or showcase the statuesque look of a Bob Paris.

At the same time, perfection is not a requirement for competitive success, or even necessary in order to build a Mr. Olympia winning physique, as some of the best bodybuilders of all-time have demonstrated what many would consider to be serious structural flaws. Yet, when evaluating their physiques as a whole, we see that their strong points were sufficient to overcome their weaknesses. A great example would be Phil Heath. With narrow clavicles according to even normal standards, let alone someone with Mr. Olympia aspirations, Phil was often criticized for his lack of shoulder width; a flaw which some believed disqualified him as a viable candidate for Mr. Olympia status. But, as the years went by and Phil took began to capitalize on his immense genetic gifts, which included an uncanny ability to pack muscle tissue onto his delts, this one-time flaw continued to fade until it was barely even recognizable.

Along with structure, muscle shape is critical in becoming a champion bodybuilder. Several factors play a role in determining muscle shape, all of which are genetically programmed into our DNA before birth. However, muscle shape can be modified by emphasizing the development of certain areas of a muscle/muscle group, giving one a measure of power to manipulate their natural appearance. In addition, muscle shape cannot be accurately assessed until it has been sufficiently developed, as its appearance will change dramatically by the time a bodybuilder reaches national/pro-level size. Numerous examples can be provided of professional bodybuilders who didn’t look like anything special when they first began training, yet were eventually regarded as some of the most beautifully shaped bodybuilders of all-time. Depending on one’s genetic propensity for building muscle, it can take anywhere between 5-10 years before this attribute becomes fully apparent.

Rounding out the list of external genetic factors is separation and detail, as well as conditioning. While conditioning is largely determined by diet, certain qualities observable when in contest shape, such as hardness and density, are also partially dependent on genetics. Recognized for getting in spectacular shape, Dorian Yates’ pre-retirement look exemplified the phrase “genetic freak”, displaying a type of “graininess” to his musculature which would not be possible without his unique genetic profile. Virtually every visible characteristic in one’s physique, whether positive or negative, is either directly attributed to or potentiated by one’s genetics.

While it is relatively easy to assess a bodybuilder’s potential from a purely physical standpoint, it represents only one aspect of the greater whole. When referring to pharmacologically enhanced bodybuilders, genetic response can have a huge impact on one’s ability to add muscle size, but the degree to which these drugs work is only one aspect of personal response. By and large, professional bodybuilders tend to exhibit a greater degree of tolerability to PED use than the majority of their non-professional counterparts, enabling them to use large amounts of drugs over an extended period of time while experiencing fewer progress halting side effects.

Many bodybuilders, after beginning to approach the dosages and number of compounds commonly employed by the elite will find they begin to feel physically ill, while ailments such as appetite suppression and indigestion kick in, preventing them from eating the amount of food necessary to fuel sustained muscle growth. In order to go all the way in this sport, one must be able to do what it take to get there, but if the very actions responsible for pushing one’s development to the limit are the same things holding the bodybuilder back, reaching the top will be made infinitely more difficult, if not impossible.

An often ignored factor is the ability to eat, or should I say tolerate the quantity of food necessary to maximize muscle size. I am not just referring to will power either, but the literal ability of the digestive system to cope with the quantity of food consumed. The body is not designed to continuously accommodate 2-3X as much food as would be required under normal circumstances. The loss of appetite, poor digestion and assimilation, gas, bloating, improper elimination, and general feelings of indisposition are all commonly encountered among today’s bodybuilders. On the other hand, many of the elite seem to suffer with these issues to a lesser extent than others, allowing them to sustain their eating habits over the long-term.

As mentioned closer to the beginning of this article, the right mental outlook is frequently viewed as the most important component of success among sportsmen, as it is the mind which is responsible for manifesting virtues like a strong work ethic and commitment to a task. Along with intestinal fortitude and a disciplined will, it takes a unique mind-set in order to consistently endure the sacrifices inherent in high-level bodybuilding. Most are unfit for the challenge, not because they necessarily lack discipline (although many do), but because they lack the unique mental make-up required for success in this sport. When analyzing our top champions, it becomes immediately apparent that all of them share this same common trait, enabling them to put their nose to the grindstone day after day and year after year without succumbing to boredom or straying from the structure of their routine.

One of the more fascinating topics in recent years has been that of DNA testing as a means of evaluating one’s genetic potential for bodybuilding. Now a reality, science is able to provide us with a breakdown of various genes involved in the processes of muscle growth, fat loss, muscular endurance, and recovery, thereby helping us assemble programs more in harmony with our natural genetic programming. Muscle Genes, a company that specializes in sport specific DNA testing, has been offering this service for the last couple years and has recently experienced an upsurge in popularity by making the DNA results of 8-time Mr. Olympia, Ronnie Coleman, publically available.

Recently published in an issue of Muscular Development Magazine, these results reveal pretty much what we would have expected from the freak of all freaks. One gene in particular, called ACTN3, is closely related to an individual’s ability to develop strength and power and is present in virtually every single Olympic sprinter tested by Muscle Genes thus far. There are 3 different variants of ACTN3, with Ronnie carrying the variant most likely to up-regulate anabolic signaling pathways in response to resistance training and increasing the muscles’ ability to withstand damage. Obviously, this translates into enhanced recovery and growth.

Ronnie also carries a gene shown to increase muscular endurance 11X greater in response to weigh training compared to low volume responders, allowing Ronnie to receive greater benefit from high volume training. As if that weren’t enough, the man is likewise blessed in terms of fat loss, having genes which ramp up the body’s thermogenic effect, making it far more difficult to accumulate bodyfat and much easier to get ripped. All in all, Ronnie is a bona fide fat burning, muscle building machine, possessing many of the most potent gene variants found in human beings. However, even Ronnie’s genetic profile was not perfect, revealing the presence of at least a few normal genes.

Interestingly, not all of the sport’s massively developed bodybuilders were bestowed with extraordinary genetic gifts. Dorian Yates is a great example, who, without any truly stand-out genes, was able to develop his body to the point where he broke down previously conceived limitations regarding muscular development, re-setting the standard in the process. This goes to show that even with relatively normal genes, one can, though intelligent application of the principles of bodybuilding, surpass those with more gifted genetics. At the same time, this doesn’t mean that Dorian was not a gifted individual, as he clearly was in many respects. While the genes mentioned above certainly have an influence on growth, fat loss, and recovery, they are not the only important factors.

Do you have what it takes to enjoy competitive success or even earn a pro card? Making the most of one’s genetic potential in this sport is exceedingly difficult, with few men being willing to invest the time and effort necessary to do so. More so, an equally small percentage of individuals have the genetic ability to be successful on the pro-stage (i.e. earn a living). But, even though the odds may be stacked against most, you will never know the answer to this question until you try. In a sport where genetic ability often takes years to be fully revealed, a road with humble beginnings could very well grow into something more substantial.