After two years of turmoil in Covid-19 and its exercise routines, many of us may feel like we’ve forgotten how to fit. But promising new research suggests that our muscles remember. This study included mice, but is based on weight training and similar experiments by people. It was found that muscles developed a widespread and permanent molecular “memory” of past resistance movements and helped them recover quickly from long layoffs.
In this study, animals that completed rodent strength training had changes in muscle DNA that persisted long after they stopped exercising. The mice then packed muscle mass much faster than other animals when they started training again. As an encouraging supplement to those who are new to weight training, the findings also suggest that age-independent muscle memory should be able to be built.
Until recently, the term “muscle memory” usually refers to the ability to ride a bicycle, ski, throw to first baseman, and repeat other common physical tasks. Our body remembers how to do it. However, although this type of memory actually exists, it is not really muscle memory. These memories reside within the motor neurons of our brain.
But scientists knew that something happened when the muscles themselves worked hard, especially during weight training, and that these changes affect how they later respond to exercise. rice field. “By the way,” I used to be an athlete, but I took a day off, but as soon as I started, my muscles returned to normal. ” The University of Arkansas, which oversaw the new research.
Those stories were intriguing to him and other researchers. They wondered how muscles “remember” past workouts. And how do those memories help the muscles rebound after leaving the gym?
Several preliminary studies in animals have suggested that genes in the nucleus of muscle cells behave differently after resistance exercise. Then, in 2018 and 2019, some well-discussed studies of people examined the epigenetics of resistance training. Epigenetics refers to changes in the way genes work, even if the genes themselves do not change. It involves a process primarily called methylation, in which clusters of atoms called methyl groups attach to the outside of small fujitsubo-like genes, turning the gene more or less and increasing the likelihood of producing a particular protein. increase.
In recent human experiments, resistance exercise alters the methylation patterns of many genes in people’s muscles, and even after volunteers stop exercising and lose some of their muscle mass, those changes are weeks or months. It was clear later. When they started lifting again, they restored their muscles much faster than when the study began, researchers found. In essence, their muscles remembered how to grow.
However, while those studies were intriguing, they lasted only a few months at most. It was still unclear whether exercise from long ago remains as a genetic memory of our muscles, or whether strength training epigenetically affects the number of different cells and genes in our muscles.
Therefore, in a new study recently published in Function, Dr. Murach and his colleagues, including Yuan Wen, the lead author of the University of Kentucky, the leading journal of the American Physiological Society, will recreate human weight training experiments. did. As closely as possible in adult mice. The lifespan of rodents is much more condensed than we are. That is, the changes seen in animals after a few months can appear in people years later.
However, because mice cannot use barbells, scientists ran them on weighted running wheels designed to provide strength training for the legs and muscles. The animals were trained for 8 weeks and then sat in the cage for 12 weeks. This is about 10% of life, which is years for us. The animal was then trained again for a month, with the addition of mice of the same age, just beginning to exercise and functioning as a control. Throughout, researchers biopsied their muscles and studied them under a microscope.
They noted many differences in gene methylation in muscle cells after mice were trained. Most of the changes remained months after I stopped exercising. In general, these epigenetic changes dial up the manipulation of genes involved in muscle growth, while calming genetic activity elsewhere, making the genetic process of building muscle “more sophisticated.” First, Dr. Murach said. Even after months of inactivity, these changes helped trained mice build muscle more quickly during retraining compared to previously untrained mice.
Of course, this study was aimed at mice, not humans. I also looked only at resistance exercises, not aerobic exercise.
However, many of the genes that researchers have tracked are the same as those that researchers have studied in human experiments, so the findings show who of us want to build our muscles in 2022. It is likely to be relevant for you as well.
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Even if you rarely or never lift weights, it’s never too late to start putting muscle memory. The mice under study were all adults when they started weighted wheel training, but managed to build muscle memory and become bulkier faster after a period of inactivity. “It’s better to start someday than not at all,” Dr. Muraf said.
