Is Muscle Memory Real? Exploring the Science Behind It - Coach Mark Carroll


May 5, 2022
Sheridan Skye

There’s no doubt that life happens. We get sick or injured, or our work and life commitments become so big that we take a step back from the gym. Often this makes people worry about losing muscle mass and whether they will need to start from scratch again. 

As a mum of a six-month-old and a two-year-old, there’s no doubt that my training took a bit of a back seat over the past few years. And yes, I did lose some muscle mass. However, I wanted to know if it would all be ‘undone’, and you’ll be surprised to hear the results. 

Building muscle takes a lot of time and energy. As you would know, Mark and I talk about how important it is to have an efficient and effective training program, good nutrition and efficient recovery if you want to grow muscle. But here’s the catch – it’s not nearly as hard to rebuild OLD muscle tissue as it is to build NEW muscle tissue, and this comes down to muscle memory. 

What is muscle memory? 

When you stop resistance training, you will lose muscle and strength. Strength is quicker to diminish, which happens within 1-2 weeks. Muscle will then start to decrease in size over 2-4 weeks. Why? Because like we always say, muscle tissue is metabolically expensive to keep. 

Think of it like this, if you are saving for a house and need to decrease your spending, you look toward the things that aren’t essential and spend your money only where you need to. Muscle mass is the same. It’s nice to have but it’s not essential, so your body will begin to de-prioritise building (and even maintaining) muscle tissue. This is why you lose muscle when you stop training.
Muscle memory can be skill-based, a great example of this is the old saying, ‘it’s like riding a bike’. Even when we take time away from doing a task repeatedly, it comes back to us pretty quickly but it can also relate to how fast we regain muscle. 

The reason this happens is that muscle cells have MANY nuclei. This differentiates them from most other cells because most cells contain one nucleus. 

Why does this matter? 

Resistance training increases the number of myonuclei our muscles contain, and these cells remain even after we lose muscle mass. Fibres that have acquired a higher number of myonuclei grow faster when subjected to progressive overload. The cool thing is that muscle memory might be very long-lasting in humans, as myonuclei are stable for at least 15 years and might even be permanent. This is because satellite cells that sit outside the muscle are activated when we resistance train. Satellite cells can donate a nucleus to a muscle fibre (increasing the number of myonuclei and increasing recovery). 

What does this mean for you? 

It means you don’t need to freak out if you require some time off due to illness, surgery or even if you need a break from resistance training for ANY reasons. Likewise, you don’t need to fall into overtraining when you return to resistance training. Instead, you need to show up and get back into training sensibly

How quickly does it come back? 

The answer to this question isn’t so clear. Will you accumulate 20 years of muscle growth in three months? No, you won’t – but it also won’t take you 20 years to accumulate either. Likewise, it would be best to focus on progressively overloading when you return to resistance training; it won’t happen on its own. 

Anabolic steroids – are they an unfair advantage?

Now that we know that muscle memory isn’t just a myth, what does this mean for athletes who have formerly taken anabolic steroids? Do they have an advantage over those who are natural? The answer is yes, they do because we know that anabolic steroids (with the proper training & recovery – steroids don’t do the work for you) increase muscle size and therefore, increase the number of myonuclei. So even when that athlete no longer uses steroids and competes in a ‘natural’ division, they have the advantage because of muscle memory and the number of myonuclei that their muscles contain. 

Other things to consider…. 

You might feel quite sore when you return to training. This will improve with time and exposure to the stress you’re placing on your body. You will need to start with less volume than you did previously. Junk volume won’t help you here. And don’t forget, sleep, stress management, calories and protein matter too!

Yours in health,

Sheridan Skye

Head of Nutrition