Muscle Memory – part 2

Last week we covered Part 1 – this is Part 2. The first paragraph is a recap.  References/citations are at the end.

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.

Let’s get a little deeper in the science of “muscle memory”…

Tissue Alteration

According to Staron, et al. (1991), a study was performed on women who had undergone heavy resistance training for 20 weeks and then did no resistance training for 30 to 32 weeks before retraining for 6 weeks. The results of this test indicated that although maximum dynamic strength decreased during detraining, it did not return to pretraining levels. The muscles retained some of the strength that was gained during training. The study also showed that fiber area and maximal dynamic strength may be retained for long periods during detraining and may contribute to a rapid return to competitive form.

Other studies have achieved the same result when conducted on men in their twenties who resistance-trained for 3 months and then detrained for 3 months. During their initial training, muscle strength increased approximately 18%, and while after detraining muscle strength returned to pretraining levels, movement speed and power remained increased (Anderson et al., 2005). It is believed that certain muscle fibers are actually able to change from one type to another, more effective type that encourages muscular hypertrophy. The muscle proteins that determine how muscle fiber works, MHCs, actually change type. 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. It is believed that during resistance training, IIX MHCs are recruited to become IIA MHCs, thus causing the muscle to have a reserve of proteins that encourage muscle growth, making it easier to regain size after a period of no training (Haycock, 2004). Although muscle atrophy during periods of detraining may lessen the benefit of this fiber-type transformation, the ability to perform the motor tasks involved in retraining would still be increased because of it (Andersen, et al. 2005).

Furthermore, in a study of older men who practiced progressive resistance training 3 days per week during a 12 week period and then decreased to 1 day per week, it was learned that they were able to maintain the muscle strength and size they had gained during the initial training, while those who did not continue training had a 5% decrease muscle size and an 11% decrease in strength (Trappe, et al. 2002). This could also be an example of muscle proteins being altered to be readily available for use in maintaining progress achieved during training.

This has huge implications for older people.  In case it’s not obvious, I’ll quote the study:  “Of practical importance for the elderly and health care communities is how much (or little) training is necessary to maintain muscle function and size. Minimizing the frequency and time commitment may lead to increased participation of older adults engaging in resistance training types of activities.” (Trappe, Williamson & Godard, 2002) Here at World Fitness Network, we strongly encourage older adults to do resistance training, particularly free-weight, full-bod exercises that focus on core strength and balance.  See also our recent science summary including news on weight training as you age.

An Alternate Theory

The controversy regarding muscle memory comes into play, however, when scientists disagree about the causes of gain in muscle mass. Other studies have shown that the fiber area of a muscle does not change with training, but is actually reduced after training when lifting the same loads. This may be attributed to the body’s ability to transmit more effective information with repetition (Duchateau, Semmler & Enoka, 2006). In an article we found in the Seattle Post-Intelligencer (Condor, 2004), emphasis was placed on the body’s ability to memorize a process in the form of resistance training in order to more effectively perform a task over time. This causes hypertrophy to appear to be more of a neural function than a physical alteration of muscle tissue. If muscle memory is more related to neural function, then hypertrophy may simply be a result of learning how to exercise correctly and efficiently. Once a person has repeated a process enough times for it to become natural to make the movements needed without thinking about them, their body would operate more smoothly, as if instinctively, causing their performance to improve over time.

But even this alternate theory still supports the basic premise of muscle memory – your muscles do “remember” your previous training and you can regain muscle mass more quickly after a period of inactivity than it took to gain the same mass originally.

The Need for Additional Research

Clearly more research needs to be done to determine the exact causes of muscle memory and the physical changes the body goes through during resistance training. More information is being learned every day that will be useful for our future. With the growth in size of the population of older adults, methods need to be developed to aid in the aging process that will keep people active longer and more able to care for themselves.  Some studies already done have shown people well into their 90’s can improve their strength, balance and fitness through exercise (Condor, 2004). Obesity is also an issue that must be addressed in relation to children, adults and the elderly, and if more of the population can be encouraged to engage in a process of resistance training at some time during their lifetime, the results may provide the world with a population of healthier individuals by encouraging better habits. But that’s a tangent we won’t explore more now…

The more that resistance training research is able to prove that the results are long lasting and can continue to have an overall affect on physical health even with only a maintenance program (or after detraining), the easier it will be to encourage more people to stay fit. Further studies may prove that if everyone pursues an exercise regimen at any time during their lifetime, their bodies would continue to be healthier for the rest of their lives. This might encourage schools districts, health care organizations, and retirement communities to emphasize the need for resistance training and possibly the need for a maintenance plan to ensure good health. This would lower the cost of health care and medical insurance over time, as well as elderly care. I do not think it’s an overstatement to say that bodybuilding can have a potentially immense impact on the quality of life for every person in the entire world.

REFERENCES

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.

Condor, B. (2004). Living Well: Fitness begins with muscle memory. http://seattlepi.newource.com/health/180524 condor05.html

Duchateau, J., Semmler, J. G., & Enoka, R. M. (2006). Training adaptations in the behavior of human motor units. Journal of Applied Physiology, 101, 1766-1775.

Haycock, B. (2002). Strategic Deconditioning: Priming the Muscle for Continued Growth. http://www.hypertrophy-specific.com/hst artcls stratdecon.html

Haycock, B. (2004). Muscle Memory: Scientists May Have Unwittingly Uncovered Its Mystery. http://www.thinkmuscle.com/articles/haycock/muscle-memory.htm

Jensen, J. L., Marstrand, P. C. D., & Nielsen, J. B. (2005). Motor skill training and strength training are associated with different plastic changes in the central nervous system. Journal of Applied Physiology, 99, 1558-1568.

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.

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Related posts:

1. Muscle Memory – Can Muscles Actually “Remember”?
2. Low Carb Diets Blur Memory?
3. Science News For Building Lean Muscle – September 12 2009

Tags: bodybuilding science, detraining, muscle memory