A common misconception about strength training is that once you stop working out, you must begin building muscle again from scratch. Thanks to muscle memory, returning to your previous level of fitness may actually be much easier than you imagine.
William Kraemer, a professor at the University of Connecticut at Storrs defines muscle memory as “your body’s learning not just how to perform a task, but also how to break down muscle tissue and then repair and rebuild it.” The more often you perform a certain activity, the greater your muscle memory becomes. This means that the longer you work out, the greater the amount of time that’s required for your muscles to “forget” how to rebuild themselves.
Muscle cells are among the largest ones in the body, and are also one of the few that contain multi-nuclear cells, or cells with more than one nucleus. During strength training, new nuclei are added very rapidly, which in turn allows your muscles to increase in size. These new nuclei are retained long term. Some studies suggest that these additional nuclei never die off, but instead are retained permanently. The fact that your muscles have more nuclei is what accounts for your ability to notice more rapid gains than someone who has never worked out before.
A different type of muscle memory occurs in the brain. This type of memory enables you to remember certain muscle movements. Movement patterns are stored in the cerebellum, and become a part of your long-term memory. Once they are stored there, you don’t need to focus quite as much on your movement patterns in order to become efficient. This is why golfers, martial artists, and tennis players can return to their sport years after becoming inactive without having to retrain on the basics. This type of muscle memory also helps weightlifters perform the correct movements after months or even years of being inactive.
Researchers at Ohio University had a group of women perform strength training twice a week for 20 weeks, followed by eight months of inactivity. At the end of this period, these women began training again along with another group of females who had never lifted before. Researchers noted that women in the group who had previously trained noticed faster gains that those who had not exercised in the past. Scientists at the University of Oslo also noted that mice generated new nuclei in their muscles after only six days of simulated strength training. Those nuclei remained after the rodents stopped training, despite the fact that their muscles had shrunk in size due to inactivity.
If it’s been some time since you last worked out, getting fit again may not be as difficult as you think. The concept of muscle memory works to your advantage so that starting over from scratch is not necessary. Now you have no more excuses for not beginning a new exercise regimen.