Muscle Memory Debunked
Muscle memory is probably one of the most over used word in the bodybuilding world. It’s used by almost everyone at some point or another and frankly it's down right wrong. It's wrong in the sense that it doesn’t actually exist. Muscle memory is not a real scientific term. Sorry to burst your bubble if you’ve been living and swearing by this, but it does not exist in the world of science I assure you this. News flash, muscles don’t have brains, they can’t think for themselves. I’m sure sometimes you think they have a mind of their own, but they don’t, and they can’t remember anything like the human brain does. However, there are scientific properties that are related to the idea of “muscle memory” that are very real. It is these scientific concepts that I want to discuss and make you aware of, so next time someone pulls the “muscle memory” card on you, you will be ready to hand it back to them with the real low down!
The entire P90X training system are based on the idea of muscle memory. Why do they base it off of something that doesn’t exist? Because the idea behind it seems very real, and people are gullible and will believe anything on TV. However, the real scientific concepts of “muscle memory” include the following but are not limited to: muscular adaptations and neural adaptations in response to exercise. These are relatively broad topics so within the next few paragraphs I will discuss a few specifics on how these topics are all bound together to create the junk science term “muscle memory”.
In terms of muscular adaption post-exercise training , I have previously discussed in articles delayed onset muscle soreness, fiber type composition and increased number and the role of eccentric contractions and muscle damage. It is the combination of these three things along with increased cross-sectional area and fatigue resistance that make up the muscular adaptation that come together to make up muscle memory. The muscle does not actually remember that set of exercises you did last workout. The workout is easier this time around with the same weights and same exercises because your muscle have physically adapted the stress that it encountered last time. The body is an incredible thing and if you throw something at it, it is going to adapt to the stressor in hopes that it can combat the stress and be more prepared next time. This is why we change our workouts and change the exercises and change the weights and change the reps. Change, change, change, it’s a good thing and the only thing that should never change is the fact that you are continuously changing. 
Neural adaptations are also responsible for the bundle of terms that encompass “muscle memory”. In terms of neural adaptations to exercise there are few things that need mentioning: motor unit recruitment, motor cortex adaptation and task specificity and adaptation of the neuromuscular junctions. These things I have not touched on as much as the muscular components of “muscle memory”. So I would like to briefly touch on each one of these topics to show part of the neural side to the idea of “muscle memory”. At the onset of a training program we see rapid strength gains within the first few weeks of training. This is due to the ability of the neural circuits to work with your muscles and vice versa. The rapid increases in strength indicate greater efficiency of the two working together to perform the task. This occurs at the neuromuscular junction. Also this has to do with the motor unit recruitment. For example, say you decided to leg press only the platform, with no weight added. This is going to be relatively easy for you to do. However, say you added 8 plates to the machine. You then go to press this weight and it is entirely different, it is heavier. This is where the motor unit recruitment comes in. You nervous system actually “tells” the body “hey we need more muscles to help lift this heavier weight, because the muscles we used while lifting no weight are not going to cut it”. It is a great phenomena and without it you really would be able to do anything except carry your own body weight around. That brings us to task specificity. Task specificity is also evident after prolonged training programs. That is that the muscle is more efficient at performing the task when performed over a period of time in workouts due to the ability of the nervous system to convey signals to the muscle. In terms or motor cortex changes in response to exercise this actually has to do with the brain. With repeated exercise of the same movement your brain actually partially contributes to the ease of being able to do this exercise. This makes sense and is seen in other aspects of human function unrelated to exercise. All of these examples indicate neural adaptations are partially responsible for concept of muscle memory.
So now know
ing what you know from this and previous articles you can let everyone know that muscle memory is not a real term! While it is easy to throw it around and use it casually, it really has no validity. But after reading this you can see why someone just said, “hey, muscle memory”. Because there are entirely too many things that make it up to be able to talk about in a single conversation to someone, it is conveniently compiled into a single term which, technically doesn’t exist. You will also never see in the professional science journals. It’s more of a topic for over dinner or a longer conversation setting in which all the components can be discussed.
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