What is Muscle Memory?

According to the bro-science definition, muscle memory is when a person is able to quickly gain back muscle mass that's been lost due to injury or layoff.

Maybe it took a guy years to build 15 pounds of muscle, then that muscle was lost because he quit training or got hurt. When he gets back into the gym, he seems to build that 15 pounds back at a much faster rate than it initially took to build it.

Like a lot of bro-science, this is actually true. Experienced gym bros usually figure things out before the scientific studies are done. Science often just confirms it or figures out the exact mechanisms involved, which is cool.

Now, a new study confirms that muscle memory exists at a DNA level, but the implications of this discovery are controversial.

The Study

Researchers at Keele University took a look at 850,000 sites on human DNA. They figured out that when muscles grow after training, genes get marked or unmarked with chemical tags, a process known as epigenetic modification. The chemical tags instruct the gene to turn off or turn on without changing the DNA itself.

Dr. Adam Sharples sums it up: "...we've demonstrated the genes in muscle become more untagged with this epigenetic information when it grows following exercise in earlier life. Importantly, these genes remain untagged even when we lose muscle again, but this untagging helps 'switch' the gene on to a greater extent and is associated with greater muscle growth in response to exercise in later life, demonstrating an epigenetic memory of earlier life muscle growth."

The Controversy

Okay, so muscle memory exists and now we know a little more about how it works. And it's comforting to know that we can indeed make a faster comeback after an injury or even a years-long layoff due to this phenomenon.

So what's the big deal? Well, it has to do with anabolic steroid usage. Another researcher involved noted:

"If an elite athlete takes performance-enhancing drugs to put on muscle bulk, his muscle may retain a memory of this prior growth. If the athlete is caught and given a ban, it may be the case that short bans are not adequate, as they may continue to be at an advantage over their competitors because they have taken drugs earlier in life, despite not taking drugs anymore."

So, this could lead to longer bans in pro sports. And this makes "natural" bodybuilding competitions a little trickier, doesn't it?

In most cases, a natural or tested competition only means that the bodybuilder hasn't used drugs for a certain period of time. It does not mean that the competitor is a lifetime natural. And that guy (or gal) will have an advantage over the competitors who've never used.

In short, earlier steroid use means (according to this research) that the competitor will still be able to build more muscle mass than he could have otherwise done naturally, even if he hasn't used for years.

Bodybuilders have theorized about this for decades. Most know that while muscle will be lost when steroid use is discontinued, not ALL of it will be lost. And this study implies that perhaps they'll always have an advantage.

Not a bad deal for the responsible recreational user, but a big asterisk for those who compete in drug-tested sports.

Related:  Natural vs. Enhanced Lifters

Related:  The Effects of Mild Cycles


  1. Robert A. Seaborne, Juliette Strauss, Matthew Cocks, Sam Shepherd, Thomas D. O'Brien, Ken A. van Someren, Phillip G. Bell, Christopher Murgatroyd, James P. Morton, Claire E. Stewart, Adam P. Sharples. Human Skeletal Muscle Possesses an Epigenetic Memory of Hypertrophy. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-018-20287-3