Long-lasting genetic changes at the molecular level give scientific insight into how athletes rebuild their fitness to previous levels after taking an extended break from their bikes.
It’s just like riding a bike. Truth be told, when I got my first car as a teen, riding a bike immediately became an obsolete notion. To expend a tremendous amount of energy to go a fraction of the distance in twice the time. The equation didn’t work in my immediate gratification world.
A world where my bike was a means, and the end was to get from one place to another. My car was much better at that and way cooler to drive.
As things go, with time comes maturity, and experience provides perspective. You look at things differently the more stuff you get to look at, and my bike was one of them.
When I pulled it from my parent’s shed, dusted it off, and hopped onto the saddle, I found it was true. Riding a bike was just like riding a bike. Maturity, experience, and seeing stuff also make you justify the time with fancy terms to explain simple things.
Muscle Memory is NOT a Thing
“Muscle memory,” I said to myself. My muscles remembered balancing and pedaling despite not having done it for years. It seemed a feasible explanation then, but I came to find out during my science schooling that muscle memory in this sense is not a thing.
Muscles don’t remember, and balancing is the job of memory connections within motor neurons in our brains. The more I rode, the more serious I became, and my bike became a means of training, and the end was racing.
The more I rode, the easier it was to get back into race shape when life forced me from my bike for weeks, even months at a time. It took me years to get to the point I was, but only a relatively short time to get back after being away for a long while. Each time it was shorter yet.
“Muscle memory,” I shamefully whispered in my mind’s dialogue for fear that someone who knew better, like me, would hear that I had repeated my mistake. Then it occurred to me my science education had taught me that muscle memory is a thing in this sense.
Epigenetics IS a Thing
Epigenetics—the fancy term went far towards justifying the time and my education’s tremendous expense. Epigenetics describes the scientific theory explaining changes in how genes function despite not undergoing any changes to the genes themselves.
An October 2020 study reviewed the interplay between epigenetics and a human muscle’s response to strength exercise. Preliminary animal studies uncovered that genes inside a muscle cell’s nucleus work differently after resistance exercise.
The researchers discovered that in humans, epigenetic changes in the muscle come in the form of methylation. Methyl groups, atom clusters that attach themselves to the genes of muscle cells during or after exercise, make the genes more or less effective at producing proteins conducive to strength training.
The methylation patterns seen after resistance training remained for weeks or months in the tested subjects, even those who had stopped exercising and lost muscle mass. When they resumed strength training, the subjects gained strength and put on muscle more rapidly than at the beginning of the experiment.
Our Muscles Remember How to be Strong
The studies reviewed were short-term, lasting a few months at the most. Unless my muscles were Albert Einstein-level genius, it doesn’t explain how I rebounded after a half-year break. It was unclear how long-lasting muscle methylation memory persists and the implication to athletes.
Researchers delved into this in an August 2021 study by recreating human weight-training experiments on adult mice. Scientists use mice for many reasons, and one is the cross-over with humans when compared over a shorter lifespan.
In theory, it allows researchers to extrapolate changes seen in animals after months to people after years. Ten percent of a mouse’s life passes in about 12-weeks, the equivalent of a human year.
The scientists rigged up a weighted running wheel designed as leg muscle resistance training for the mice—12-weeks of detraining followed the eight-week training period. A control group of mice that hadn’t run on the weighted wheel joined the trained group for another month of resistance wheel running.
The researchers found significant gene methylation in the trained mice after microscopic examination of muscle biopsies. The epigenetic changes lasted months after the mice stopped exercising.
It facilitated the genes employed in muscle growth and decreased gene activity in other areas making the genetic muscle building more efficient and effective. In addition, the trained mice regained their muscle mass and strength more rapidly when compared to the control group after a relatively prolonged period of inactivity.
Conclusion—Your Muscles Don’t Forget and You’re Never Too Old to Remember
Many of the genes the researchers tested in mice were equivalent to previous studies conducted on humans. The thought exists in humans that the resistance training effect is also similar, and a lengthy layoff doesn’t jeopardize previous gains. Moreover, since the mice studied were in the adult phase of their lifespan, the scientists believe our muscles are never too old to learn.
In mice and humans, muscle memory and epigenetics don’t fully explain why riding a bike is like riding a bike. However, it does give a cyclist hope that when life gets between us and our bikes, we can achieve the level of performance previously enjoyed. That is a hope I will never forget.
Have you experienced an epigenetic muscle memory moment during your cycling career? Comment below! Your fellow virtual cyclists want to know.
For more helpful cycling performance-related information check out the Training & Performance page of The ZOM!
Semi-retired as owner and director of his private Orthopedic Physical Therapy practice after over 20 years, Chris is blessed with the freedom to pursue his passion for virtual cycling and writing. On a continual quest to give back to his bike for all the rewarding experiences and relationships it has provided him, he created a non-profit. Chris is committed to helping others with his bike through its work and the pages of his site.
In the summer of 2022, he rode 3,900 miles from San Francisco to New York to support the charity he founded, TheDIRTDadFund. His “Gain Cave” resides on the North Fork of Long Island, where he lives with his beautiful wife and is proud of his two independent children.
You will read him promoting his passion on the pages of Cycling Weekly, Cycling News, road.cc, Zwift Insider, Endurance.biz, and Bicycling. Chris is co-host of The Virtual Velo Podcast, too!