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Are Your Genetics Good for Bodybuilding—And Does it Matter?

Are Your Genetics Good for Bodybuilding—And Does it Matter?

Reading Time: 7 minutes 27 seconds


DATE: 2023-09-13

Building muscle and strength requires hard work and time. You have to strength train, eat right, get enough sleep, and be patient to see results. But if you’ve ever thought it’s easier for some people than others, you are right. 

Your particular set of genes determines, to some extent, how easy or difficult it is to build muscle and get strong. Yes, everyone can see improvements by doing all the right things, but some people are more limited. 

Is it possible to know if you have the right DNA for bodybuilding? Or is it a matter of trial and error? Are some people naturally muscular without working out or putting in long days in the weight room? Are you out of luck if you have bad chest genetics or bad ab genes? Whether for you or your training clients, a lifestyle or health and fitness genetics test can provide some answers and direct your fitness program. 

How to Know if Your Genetics are Good for Bodybuilding? Take a Test

Don’t worry, it’s an easy test. Lifestyle genetic tests are increasing in popularity, and they are more affordable than ever. All you need to do is order a kit, send a sample to the testing company, and wait for the results. 

The advances in DNA technology are great for health and fitness. These tests can help you determine your specific strengths and weaknesses when it comes to working out, building muscle, nutrition planning, and losing or maintaining a healthy weight. 

If you’re a trainer, you are probably already fielding a lot of questions about these DNA tests. Your clients want to know more about them, if they are worth the cost, and if they can help them get fitter or meet their weight goals. 

For strength training, the right genetic test can give you some important answers. Some of your clients may respond really well to lifting and be suited to bodybuilding. Others may struggle to see gains when they lift or strength train. 

What the results of the test can tell you is how to change their workouts to meet their goals most efficiently. Even for those clients who just aren’t destined to be a bodybuilder, DNA test results can guide program planning so that they get as many benefits from strength training as possible. 

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Bodybuilding, Strength Training, and DNA

It’s obvious that our genes play a role in fitness. Long before we understood so much about DNA, good genetics, and health, it was clear that some people just build muscle more easily. Bodybuilders work hard to get chiseled bodies, but many also have a boost from their genetics. 

One important gene that has been studied and proven to impact strength and muscle size is called ACTN3. This gene codes for α-actinin-3, a protein in fast-twitch muscle fibers. It’s these types of fibers that allow muscles to contract rapidly. They are necessary for power sports, like weightlifting and sprinting. 

Studies have found that a lot of people have a defective version of ACTN3, which means the protein cannot be made. Among elite power athletes, the functional version of the gene is much more common than in the general population (1). So if your genetic test showed you have the functional ACTN3 gene, it means you probably have an advantage in strength training and bodybuilding. 

ACTN3 is just one of several genes that contribute to an individual’s ability to put on muscle mass and gain muscle strength. Genes are complicated, and we still don’t fully understand how they all interact to make each person unique. Several genes, and probably many more to be discovered, have an impact on bodybuilding abilities. 

Genetics, Body Composition, and Weight

One piece of information you can get from a simple lifestyle genetic test is how strength training or bodybuilding will affect your body composition and your weight. Body composition is a description of how much of your body’s mass is from fat and how much is muscle. 

Of course, most people prefer to have less body fat and more muscle, but bodybuilders take this to the extreme. They work very hard, both on diet and training, to minimize fat as much as possible while building muscle. 

Hard work is key, but your genetics also play a role in how much or how easily you can change your body composition. A genetic test can give you a measure of your body composition response to strength training. 

Several genes have been determined to have an impact on how the body responds to strength training. A test will give you one of three genotypes for this measure: 


If you have an “enhanced” genotype in this category, bodybuilding could be your sport. It means that you will see significant gains in lean muscle mass, losses in body fat, and weight loss in response to regular strength training. 

For achieving basic body composition goals, someone with an “enhanced” genotype only needs to strength train two to three days per week. However, if you have a client with this genotype, you can help them achieve more by incorporating strength work four to five days per week. 

Make sure that your “enhanced” clients’ workouts are varied and that you change the reps and sets from one session to the next. This will challenge the muscles in novel ways that maximize the benefits of strength training. 


Expect most people to fall into this category. This genotype means that you will lose some weight and convert some body mass by doing regular strength training workouts. The results will not be as quick or noticeable as in people with an “enhanced” genotype. 

These clients will get optimal results from strength training three times per week along with regular cardio workouts. Make sure that your “normal” genotype clients lift weights that are heavy enough to stimulate new muscle tissue growth. 

Below Average

If a client gets a “below average” result for this measure, it means strength training alone will have a minimal impact on body composition and weight. They need to do more challenging strength sessions to really stimulate muscle growth. 

For this group, workouts that include strength training but also elevate the heart rate are especially beneficial. Kettlebell workouts, for instance, will help build muscle and also rev the metabolism for greater fat loss. Include at least one power strength session per week, using very challenging weights, for “below average” clients. 

Everyone Can Improve Body Composition

It's important to keep in mind that everyone should work on achieving a healthy body composition. Whether your client gets an "enhanced" or a "below average" result, strength training will help them build muscle and lose fat, and this has a big impact on overall health. Your client should still work each muscle group to build that chest muscle or improve their triceps and biceps. Chest growth or any muscle growth doesn't happen overnight, even if you have good chest genetics.

In addition to strength training, talk about the important role of diet in minimizing fat and promoting muscle growth. Even the best exercises can only get you so far on a bad diet and too many calories.

Losing fat and lowering your body fat percentage is much harder for some people than others, but it doesn’t have to be impossible. There are a lot of strategies for improving body composition that are effective, even for those with an unfavorable genetic profile or body type. 

Genetics and Power Potential

The ability to change body composition is essential for bodybuilding, but so is power. Sports can be roughly divided into power and endurance. Power sports, like bodybuilding and weightlifting, require short bursts of big force. Endurance sports, like distance running, require less force generated over a longer period. 

Both kinds of athletics require training and hard work, of course, but again, your genes also play a role. Some people have a genotype that makes them better at power or endurance. Much of this is related to muscle fiber type. If you naturally have more type I fibers, you are more likely to be good at endurance. If you have more type II, fast-twitch fibers, power is your strength. 

Learn more: Type IIa Muscle Fibers and Training for Explosiveness

Higher Endurance

The higher endurance result means that a client is not likely to be good at power sports, like bodybuilding and weightlifting. It doesn’t mean they shouldn’t strength train, of course, it just means they won’t be the best in power sports. Focus more on endurance training to help these clients meet goals. 

Equal Endurance/Power

This is the most common genotype in this group. Most people are equally inclined to develop power and endurance from training. They may not be world-class sprinters or lifters or the best marathoners, but they are good at sports with a mix of endurance and power: 5K races, mountain biking, soccer, or middle-distance triathlons, for instance. 

Don’t discourage these clients from trying full power or endurance sports. There’s no reason not to try them. However, when it comes to training for fitness and athletic goals, they will need a good mix of both types. 

Higher Power

These are your potential bodybuilders. With a genotype for higher power, strength training will lead to major gains in power sports. These people are generally good at things like powerlifting but also sprinting. Use a lot of power workouts for these clients but don’t completely neglect endurance. 

So, What if You’re Not Built for Bodybuilding?

All this information is interesting, and it can be useful, but when it comes down to health and fitness does it really matter if you aren’t right for bodybuilding? The answer is yes only if you have dreamed of being a top fitness competitor. 

If that’s not your dream, it’s perfectly ok to be a poor match for bodybuilding. It doesn’t mean you can’t or shouldn’t strength train or focus on muscle hypertrophy. It doesn’t mean you can’t be healthy, fit, and strong. And it doesn’t mean that you can’t meet reasonable body composition goals. 

In fact, knowing your genetics and how they relate to strength and muscle building can help you better meet those goals. The answers from a genetic test can direct your fitness plan and help you build your own or a client’s workouts to maximize results. 

The truth is that, regardless of genes, strength training is important for everyone. All your clients should be doing some type of strength or resistance training at least a couple times per week. If you have a client with unfavorable genetics for bodybuilding and who is frustrated by a lack of building bigger muscles, help them understand all the benefits of strength training that are so much more important than appearance: 

  • Strength training builds strength, which improves daily functioning. 

  • Being stronger also reduces the risk of injuries and pain. 

  • Lifting weights also builds bone strength and can even slow bone loss due to aging. 

  • Resistance training improves joint mobility and flexibility. 

  • Strength training improves athletic performance. 

  • In older adults, strength training improves balance and reduces falls. 

When working with clients on strength training, remember that you can vary strength workouts and do a lot of different exercises to build muscle. It doesn’t all have to be lifting. For instance, a yoga workout can be great for strength and may feel less intimidating for certain clients. 

DNA-Based Fitness Training

Genetic testing is a great tool for finding out what you or your client should be doing for optimal health and fitness. But don’t let your clients who get disappointing answers get discouraged. Good biceps genetics or good chest genetics aren't the only factors in building muscle. Help them see that their unique DNA simply allows you to tailor their workouts for better results. 

Expect to see more clients asking about health and fitness genetic tests and be prepared with the right answers. Check out ISSA’s DNA-Based Fitness Coach certification course to learn how to use genetic test results to help clients.  

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This distance education course covers training, recovery, motivation, and nutritional strategies to prepare the personal trainer to work with bodybuilders.


  1. Eynon, N., Hanson, E.D., Lucia, A., Houweling, P.J. Garton, F., North, K.N., and Bishop, D.J. (2013, September). Genes for Elite Power and Sprint Performance: ACTN3 Leads the Way. Sports Med. 43(9), 803-17.

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