5 Key Ideas from Dr. Andy Galpin’s Presentation on “Genetics vs. Performance”
Written by Calvin Sun

We recently had the pleasure of hosting Dr. Andy Galpin, professor of kinesiology and researcher at Cal State Fullerton, at our downtown Invictus location for his presentation titled “Genetics vs Training: What Determines Your Performance?”. Galpin’s team at CSU Fullerton is probably best known for their research in advanced methods of muscle fiber typing. You might recall that we featured a guest post by Invictus member and fellow research scientist, Dr. Irene Tobias, regarding their fundraiser to help make some of their latest research possible. In this presentation, Dr. Galpin shared some of the initial results of that publically funded research as well as his thoughts on the role of genetics and training in human performance.

In case you weren’t able to attend the talk in person, we have the full 2-hour presentation available to view on our YouTube channel. If you’re pressed for time or just want to get an idea of what to expect from the presentation, here are my own summarized notes from Dr. Galpin’s presentation for your enjoyment.

1. More Myonuclei = Bigger Muscle Cells

Dr. Galpin shared some research that has found muscle growth at the cellular level to be largely determined by the number of myonuclei in a muscle fiber/cell. In case you’re confused about the terminology, the prefix “myo-” means muscle, so “myonuclei” simply refers to the nuclei found in muscle cells. Normal cells typically have one nucleus, however, muscle cells are one of the few multinucleated cell types. Dr. Galpin discussed a concept known as “myonuclear domain”. He used an analogy of each individual myonuclei as a “manager” in charge of a specific portion of the muscle fiber. Not enough managers means you can’t get any bigger, an apparent truth in both business management and muscle physiology. Hypertrophic focused training such as traditional bodybuilding increases the number of myonuclei, but he also mentioned that use of exogenous testosterone (aka androgenic anabolic steroids) can significantly increase the number of nuclei. This is pretty interesting as steroids are often thought to provide transient changes in muscle physiology and increases in human performance. The assumption being that an athlete won’t have a competitive advantage after abstaining from use. However, the current research suggests that steroid use can result in long-term physiological changes that persist after the athlete has stopped taking exogenous hormones. For me, this brings up a variety questions about how drugs should be regulated in sports… but that’s an entirely different discussion so I’ll save my thoughts on that for another occasion.

2. Hyperplasia Is Not A Myth

In terms of hypertrophy, we’ve been traditionally taught in exercise physiology that muscles get bigger mostly due to increases in the size of individual cells and not due to increases in the total number of muscle cells. In fact, some textbooks will even tell you that hyperplasia (increasing the number of muscle fibers) is a myth. However, Dr. Galpin shared some images of muscle cells that were clearly splitting into more muscle fibers. I have seen previous studies on animals that found hyperplasia does occur under the right conditions. There’s some limited human studies with research on elite bodybuilders that found indirect measures of increased numbers of muscle fibers. Dr. Galpin and his colleagues have made discoveries that directly support this conclusion at the cellular level. Dr. Galpin also mentioned that having more fibers but smaller in size (think Olympic weightlifter vs Bodybuilder) is more advantageous for athletes.

3. There Are Now 5 Muscle Fiber Types

Most people tend to think that there are two or three muscle fiber types. “Slow vs fast twitch” or you may have learned Type I (slow twitch), Type IIa (fast twitch oxidative), and Type IIb (fast twitch glycolytic). Dr. Galpin shared that there are now five known fiber types: slow twitch, a hybrid of slow/fast, fast twitch, a hybrid of fast/ultra-fast, and ultra-fast twitch fibers. However, most trained individuals will have a pre-dominance of the three major fiber types.

4. Fiber Type Plasticity (aka Yes, You Can Change Your Fiber Type Composition Through Training)

For many years, there was a lot of debate over whether our fiber type composition was determined mostly by our genetics or our training. Most people have a fairly even split of slow-twitch and fast-twitch fibers and it was thought that this ratio was a fixed trait like your height. However, Dr. Galpin’s team examined a pair of monozygotic identical twins who had vastly different training habits. One who had been training for marathons for 35 years while the other was a sedentary truck driver. They found that the endurance trained twin had 90% slow-twitch fibers and 10% fast-twitch fibers while the untrained twin had 50% slow-twitch, 30% fast-twitch, and 20% ultra-fast twitch. Dr. Galpin cited other studies on identical twins that all found that training had a dramatic effect on fiber type composition despite genetics. To answer the titular question of “genetics versus training”, Dr. Galpin asserted that training was far more important than genetics.

5. The Importance of Stress

Dr. Galpin concluded his talk by discussing the importance of stressing the human body. Exercise disrupts our normal homeostatic state and induces a variety of physiological adaptations that are beneficial to both health and performance. Dr. Galpin said, “Our ability to perform is only bound by our cellular and molecular requirements for stress.” His research certainly supports this idea. We live in a civilization where humans are more comfortable than ever and are able to avoid a great deal of the physical stressors that once plagued previous generations. The irony is that we have removed these stressors only to realize that they are essential to our optimal function and growth.

Potential Applications of Knowledge

– The function of myonuclei and myonuclear domain can explain the “muscle memory” effect observed in many clients and athletes who are able to gain back muscle quickly after taking time off due to injury, illness, or other priorities that take them away from training.

-Understanding these physiological mechanisms might help training-obsessed athletes and clients feel better about taking a little time off after competition or while on vacation (i.e. the science proves you will not lose your gains).

– It may be beneficial for some clients and athletes to do hypertrophic-focused bodybuilding style training for a period of time to increase the number of myonuclei as the physiological changes to the muscle cells don’t appear to be transient in nature. Bodybuilding might be particularly useful for strength athletes when applied correctly. For example, the Chinese national weightlifting team does a lot of bodybuilding style accessory work in their training and they have won a few medals at the Olympics…

-It’s important for coaches to understand a client’s training history. If they were a marathon runner for 10 years, transitioning to being a CrossFit athlete that can snatch 1.5x bodyweight and do 60 pull-ups is going to take a lot of time and training compared to someone who was a gymnast for 10 years.

-We should consider other forms of homeostatic disruption as methods to increase the health and fitness of the human organism. For example, in addition to the various forms of intense exercise, we should look at heat exposure, cold exposure, and fasting as forms of “exercise” that disrupt normal homeostatic processes and induce various positive adaptations in human physiology. There is an increasing body of research that suggests that saunas, ice baths, and periodic fasting all provide health and performance benefits to humans.

Of course, these are just my own personal notes and thoughts. I would highly recommend that you watch the full presentation by Dr. Andy Galpin to get the full experience. Feel free to share you favorite takeaways from the presentation in the comments section below.

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  • Kevin

    Calvin thanks for sharing brother! Learned some valuable thing here and will def check out the video on YouTube!

    • You’re welcome, Kevin! Glad to hear you got some value out of it!