In other words, I gravitate toward sports that use slow-twitch muscle fibers—those that are better at using oxygen and sustaining aerobic activity (think marathon). Fast-twitch, on the other hand, are better at producing short bursts of strength and speed (think long jump or 100-meter dash).
But until recently, I just thought my inclination toward slow-twitch activities was more a matter of skill and personal preference. Turns out: My genes are the culprits.
AIBiotech, a Richmond, Va.-based company that provides laboratory services to drug discovery and diagnostic development organizations, invited me to take its Sports X Factor test, a panel of genetic tests that provides performance indicators so individuals know how to enhance their own physical condition.
I did a quick cheek cotton swab test, and five days later, I had the results. According to the report, I have the lowest possible “score” for the gene that’s necessary for producing fast contractions, and the highest “score” for slow-twitch muscle fibers and endurance. And those results make perfect sense to me, based on the sports that I like and those in which I have some level of success.
“You have an endorsement of our science here,” said Tom Reynolds, executive vice president of Science and Technology and one of AIBiotech’s founders. Trained as a molecular biologist and geneticist, Reynolds said he and his partners have backgrounds in research and development and had been studying genetics for a long time. “Among the genes we were familiar with, one of the common threads is that they played some role in muscle physiology and metabolism,” he said. “They all went together with athletic performance.”
Sports X Factor rolled out earlier this year, and Reynolds said the $200 test is being marketed to every demographic—from soccer moms who are wondering whether their kid is prone to an ACL injury; to high schoolers who are thinking about getting into sports at a higher level and wondering if they have the gene for hypertrophic cardiomyopathy (a genetic condition that can cause sudden cardiac death in young athletes); to amateur and professional athletes wondering if they have a marker that creates an inflammatory response after a concussion.
“The things we can tell with this test are pretty big issues for someone going into sports,” Reynolds said. “And athletes are always looking for the next greatest thing. They’ll spend $200 on a pair of tennis shoes.” While he said the report doesn’t have any definitive meaning and is not designed to prevent people from playing sports, the information can help athletes make informed decisions about maximizing performance in strength, endurance and muscle growth while minimizing risk.
Furthermore, personalized medicine—customizing medical treatment to fit the individual—is a growing trend, and Reynolds says that knowing about markers such as those for athletic performance will change the way medicine is performed in the future. “It’s about understanding your genetics,” he said. “Eventually, people will go to their doctor and get their DNA sequence, and you’ll be able to treat a person based on those findings before [a disease] even happens.”
Reynolds said using next generation sequencing—technology that has lowered the cost and improved the efficiency of DNA sequencing—has allowed AIBiotech to look at all the different genes for Sports X Factor on a single run. Reynolds said each run costs $3,000 to $4,000, but the cost per sample is fairly inexpensive. “Using next generation sequencing, we can run hundreds—if not thousands—of samples on one run,” he said.
Here are some of the genetic markers tested:
- DI01: The protein encoded by this gene is involved in thyroid hormone activation. Higher isometric grip strength and leg-extensor strength has been connected with this gene.
- NOS3: A small change in this gene has been studied and found to be associated with elite power sports performance. The gene has a lot to do with testosterone levels. It is usually associated with muscle-building capacity.
- IL6: One small change in this gene is associated with sprint/power sports performance. Reynolds says this gene has to do with regulation of energy.
- ACE: This has been shown in studies to have positive effects on athletic performance. It is necessary for producing fast contractions and is associated with leap power and sports performance.
- ACTN3: This is the gene that has to do with fast and slow twitch muscle fibers.
Based on the score AIBiotech assigns to each of these performance indicators, I received 10.7 out of a total of 14 points, which puts me in the 80th percentile for endurance. My percentile for power wasn’t nearly as impressive. What does that mean for my personalized fitness plan? I’ll stick to paddling on calm waters and skip the power-lifting events.