Over time, I’ve had a lot of new and not so new runners ask me the $64,000 question about running: “How do I get fast?”
I usually spout off all the cliched answers: Increase your mileage. Focus your speed sessions. Blah. Blah. Blah. Blah.
But really, speed is like height or hair texture. You can do things to enhance your physical traits, like wear high-heeled shoes if you are short or dye your hair a different color. But when you take your shoes off, and when those roots start to show, you are who you are.
Same with speed. Your body is built with some pre-set factory conditions that can’t be undone by Yasso 800s or 20-mile long runs. To be sure, you can become a more efficient runner with more quality runs, but there is a limit to the improvement you can make. A veteran runner who trains about 40 miles a week and can run a 20-minute 5K will not turn into a Kenyan-quick 15-minute 5K on 80 miles a week.
And so in the beginning, it’s about your parents. The kind of genes they passed on to you could be the difference between your potential to run a 5K in the 17s or the 20s.
Fast twitch, slow twitch: What do you have?
There are two widely discussed traits that can help determine your running potential. Your V02Max, and how many so called “slow-twitch” and “fast-twitch” fibers you have. In a later post, I’ll get more into V02Max and how you can use it to set training paces to get faster.
But in this post I’m gonna talk about fast- and slow-twitch muscle fibers.
Now these kinds of fibers are exactly what they sound like. Most sprinters, like Usain Bolt, have an abundance of fast-twitch muscle fibers. Fast twitch fibers contract quickly and powerfully but fatigue very rapidly.
Many accomplished long-distance runners also have some fast twitch muscle fibers, but they have a ton of slow-twitch, which work far much longer than fast-twitch muscles, but not with as much force.
So to recap: sprinters = fast twitch muscle fibers. distance runners = slow-twitch fibers. And you get the genes for these muscle fibers from your parents.
What the science says about me
I always thought I had more than my share of fast-twitch fibers. My times in shorter distances are much faster than what my times should be for longer distances. I’ve run a 5K in 19:08, but my best time for a half marathon (1:31) and whole marathon (3:36) are much slower than my 5K potential.
Anyway, last summer, I was tootling around on the web and came across an ad from 23andMe which is one of the premiere personal genomics and biotech companies which provides genetic testing for hundreds of traits and diseases as well as a complete DNA profile. (23 is the number of pairs of chromosomes that each of us has.)
Turns out, 23andMe has been offering DNA testing services since November 2007 and by 2011, it had accumulated a database of more than 100,000 people. Yet few of those people were black people, so the genetics testing company had little information about the traits and DNA profiles of African-Americans. So 23andMe put out an ad soliciting the DNA samples from black people. Free of charge. I saw that ad. Sent in a sample and got my results back about a month later.
The test told me lots of things I already knew about myself: That I was likely lactose intolerant, that my eye color was likely brown, and that I had decreased odds of developing male pattern baldness. It also told me that, among other things, that I had a high risk for developing asthma and for having celiac disease (allergic to wheat products).
And it also confirmed that I have one of the genes that produces fast-twitch muscle fiber. According to 23andme, “Many world-class sprinters and some endurance athletes have this genotype.” The only way I get a copy of this gene (called ACTN3) is through my parents. Some people have two working copies of this gene which are found in most all world-class athletes. And others have no working copies of this gene. They have an abundance of slow-twitch muscles.
These results do not surprise me at all. I’ve always known I was more developed as a sprinter than as a long-distance runner. Just look at my race results. My long-distance races do not add up to what I can do in shorter distances. For example, my 5K PR is 19:08. According to most running calculators, a person able to run a 19-minute 5K should be able to run a sub 3:10 marathon. Yet my personal best marathon is only 3:36.
Clearly, I need to work more on endurance and less on speed during workouts and it’s good to know that my DNA results from 23andme back that up.