Muscle Memory- Can Muscles Actually Remember?

Ask any bodybuilder what muscle memory means and they will readily answer that it is the ability to regain muscle mass more quickly after a period of inactivity than it took to gain the same mass originally. However, if you type the term "muscle memory" into a search engine on the internet, you will find there are many different interpretations of this term. And depending on which authority you consult, the meanings are diverse.
 
Some believe that muscle memory is simply the application of learned processes much like a baby learns to walk or feed itself. After many repetitions of the same action, parts of the body are able to react without the person thinking about what they are doing, and the action involved seems to come naturally. If this is true, then muscle memory is actually a neurological function that is built into all humans. According to Andersen, et al. (2005), some studies have shown that neurological and physiological changes occur during skill training, but not during strength training alone.
 
Others believe that there is an actual physiological change that occurs in the muscles during strength training, altering the function of certain muscle fibers, causing them to bring about muscle growth more readily than before training. In both cases, the muscle's ability to regain both strength and size may be enhanced if training is stopped for a period of time and then started again.
 
Resistance training and weight training require a combination of strength and motor skill. As a person learns how to perform certain exercises, it is important to learn the right patterns of movement that will achieve the desired muscle growth (Jensen, Marstrand & Nielsen, 2005). Many people define muscle memory as muscular hypertrophy, kinesthesia, proprioception or a result of neuromuscular facilitation. To some extent, all of these definitions play a part in muscle memory. Let's start by defining these terms and showing their interaction with one another to facilitate "muscle memory" during strength training and bodybuilding (as well as other types of exercise).
 
Muscular Hypertrophy is the increase of the size of an organ or select area of tissue that occurs due to an increase in the size of cells. Muscular hypertrophy occurs through increased contractile proteins. Myosin heavy chain isoforms, or MHCs, refer to the types of protein seen in a given muscle fiber.
 
MHCs determine how the muscle fiber functions. There are two types of MHCs - IIX, which are neutral until they are put to use by the muscle, and IIA, which have a specific purpose of causing muscle growth. Certain MHCs undergo a change in response to resistance exercise and serve as a reservoir of sorts for muscle hypertrophy because they can transform themselves into the types of fibers which grow easily in response to training (Haycock, 2004). Many scientists believe that once these types of muscle fibers are generated by regular resistance or weight training, they remain in the muscle, waiting to be reactivated. If a person does not exercise, or detrains, for a long period of time, and then begins an exercise regimen again, the fact that there are an abundance of muscle-growing fibers already present from previous workouts helps to regain muscle more quickly the second time around. In fact, certain types of strength training advocate detraining for a period of time in order to facilitate this type of response in the muscle, therefore eliminating the possibility of hitting a plateau that is difficult to overcome (Haycock, 2002). Without that plateau, a bodybuilder is better able to continue growing in muscle size and strength.
 
Kinesthesia is the body's ability to sense the position and movement of all parts of itself, such as limbs and muscular tension. For example, if a person closes their eyes and holds their arms straight out in front of them, they are able to tell without looking if their palms are facing up or facing down. For a bodybuilder this translates into the body's ability to know the precise location and position to stop during a repetitive exercise in order to achieve the right amount of flex and tension to maximize the results. If you've taken part in a good program of resistance training, you will retain the ability to repeat the correct movements even if you stop training for a while.
 
It is important to note, however, that learning the correct way to perform an exercise is the key to achieving the best results. If a person learns the wrong movements, they will not achieve the same results. It is best to use a personal trainer or receive some sort of instruction when learning to exercise the different muscle groups, because learning the wrong form can cause damage or result in a workout that does not meet the exerciser's goals. And the time and effort involved in unlearning bad technique can be substantial and can totally demoralize the individual.
 
Proprioceptive Neuromuscular Facilitation is the term used to describe stretching exercises that increase range of motion in a muscle, thereby increasing strength and flexibility. It is often used as therapy after an injury or long periods of inactivity such as bed rest. By stretching and contracting and rotating a muscle, sufficient use can be regained even though the muscle has not been used as much as it would be normally, thus allowing a person to regain normal function. Stretching is an important part of physical fitness because it prepares the muscles for the physical activity involved in performing certain movements. It can reduce muscle strain and the danger of injury during a workout session. In order to be in top physical condition, a person must have good flexibility. Of course, there are different types of stretching for different routines.
 
Is Muscle Memory a Myth or Fact? Many articles and studies exist that discuss whether muscle memory in relation to bodybuilding and weight training is a myth. Some experts believe that muscle memory is simply a normal function of the body, that it is more related to the way the brain sends signals when performing any movement. However, we'll use the term to define the memory of a learned pattern of behavior, such as how to make the correct movements while performing resistance training exercises to obtain optimum benefit.
 
Based on my interpretation of the literature, as well as my own experience, muscle memory is real and does have an impact on a person's ability to regain muscle mass quickly after a period of no exercise when they previously practiced a regular exercise regimen. A good analogy is learning to ride a bicycle or learning how to swim - once a person learns how to do these things, even if they don't do them for a long period of time, they are able to operate the pedals and retain their balance on a bicycle, or kick their feet and rotate their arms to stay afloat when swimming.
 
Sources:
Andersen, L. L., Andersen, J. L., Magnusson, S. P., Suetta, C., Madsen, J. L., Christensen, L. R., & Aagaard, P. (2005). Changes in the human muscle force-velocity relationship in response to resistance training and subsequent detraining. Journal of Applied Physiology, 99, 87-94.
Staron, R. S., Leonardi, M. J., Karapondo, D. L., Malicky, E. S., Falkel, J. E., Hagerman, F. C. & Hikida, R. S. (1991). Strength and muscle adaptations in heavy-resistance-trained women after detraining and retraining. Journal of Applied Physiology, 70, 631-640.
Trappe, S., Williamson, D., & Godard, M. (2002). Maintenance of Whole Muscle Strength and Size Following Resistance Training in Older Men. Journal of Gerontology: BIOLOGICAL SCIENCES, 57A (4), B138-B143.
 
Darrin Clement runs http://worldfitnessnetwork.com, a blog covering the Art and Science of Building Lean Muscle Mass and An Awesome Physique. Sign up and get our free e-book on bodybuilding.