Genetics and Your Potential to Build Muscle

Last week I struck up a conversation with a friend's girlfriend about her training and physique. The girlfriend, who we'll call Lisa, is very muscular, much more so than myself or any other friends of mine. In fact, it's easy to notice her physique even through baggy pants and a sweatshirt. As you may suspect, I was curious to investigate.

Currently Lisa works with a trainer doing extremely high repetition sets in a total body routine, three times per week. That seems to go against the low repetition, heavy weight, once or twice-a-week principles of high intensity strength training that I preach...doesn't it? Well, let me tell you the whole story.

Lisa has been very muscular her whole life. It was even very noticeable when she was five years old! She didn't pick up strength training till she was in her late teens. She did try to run cross country track before then and was unable to, so she joined the sprint team. Lisa mentioned that she has been larger than her current physique, especially when using heavy weights and training each muscle group once a week. She was unhappy with her size, so she started training three times a week (not allowing for proper muscle recovery and therefore, overtraining) and using lighter weights, which combined to bring her muscle mass down to a size she is happier with. Most importantly, Lisa says she has NEVER used steroids. How is this possible? Here are the genetic factors that control every individual's physique, including why you will never become like Lisa, or, for a very small percentage of you, why you are similar to Lisa:


1. Fiber Type: I spoke previously about muscle fibers and how each are different. Well, for simplicity purposes, we have some muscle fibers that are built for size and produce maximum power in short bursts (strength training, sprinting) and some that are smaller and specialize in long duration activities. People are born with different percentages of each. Lisa is likely to have more of the powerful larger fibers, especially considering that she was unable to run cross country but did well on the sprint team.

2. Muscle Belly Length: some people have longer muscles than others. A simple way to understand this is to flex your elbow and contract your biceps muscle. If you have a long muscle belly, your biceps will end very close (within an inch and a half) to your elbow. If you have a long space between your biceps and your elbow (like the picture below), that means you have long tendons and your ability to build mass isn't as great. Lisa was average in this category.

3. Quantity of Muscle Fibers: If you've been in SuperSlow recently, you've heard about Wendy the whippet, a dog that looks like a bear. She, like some human beings, is born without a protein found in cells called myostatin. Myostatin limits the amount of muscle fibers in the body. When someone (or some dog) is born without it, he or she is likely to have two to three times the amount of muscle fibers one would normally have. This is possible in Lisa's case, especially considering that she was muscular at such a young age.

The point in all of this is that I see many people (mostly women) who worry about becoming very muscular if they strength train effectively (with heavy weight, few repetitions, and long rest periods). This is almost definitely NOT going to happen! Lisa had to work hard to get rid of muscle, which is something most of us have to work so hard to get! On the other hand, I've seen so many men put their bodies through so many supplements (including steroids) and crazy training routines so they can become "huge". The important thing is that you work hard, eat a decent amount of protein, and let your body produce the results it's capable of. You will gain muscle, but more importantly, strength training will make you feel better and function better, two things that are priceless.