The concept of muscle memory has long been debated among fitness enthusiasts and scientists. While it’s often thought that the effects of exercise are short-lived, new research from the University of Jyväskylä, Finland, reveals a possible explanation for muscle memory at the protein level.

In a study published in the Journal of Physiology, researchers investigated the quantities of thousands of muscle proteins after ten weeks of resistance training followed by a two-month break and then another ten weeks of resistance training. Using advanced mass spectrometry equipment, they found that muscles “remember” previous resistance training for over two months at the protein level.

The study identified two types of change profiles in muscle proteins: one group returned to their pre-training state during the break, only to change again during the new training period, similar to the first training period. These included proteins related to aerobic metabolism.

Another group of proteins changed as a result of training and remained changed during the break and after the new training period. Among these proteins were several calcium-binding proteins, such as calpain-2, whose gene has recently been identified to retain a memory trace even after a training break.

“This study shows that muscles ‘remember’ previous resistance training at the protein level for at least two and a half months,” says lead researcher Professor Juha Hulmi from the Faculty of Sport and Health Sciences. “Even though muscles eventually shrink back to their original size during a long training break, a memory trace of previous training remains in the muscles, making it easier to start training again.”

The research has significant implications for athletes and fitness enthusiasts who may be concerned about muscle loss during periods of rest or injury. By understanding the mechanisms behind muscle memory, individuals can develop strategies to maintain their gains and make the most out of their training efforts.

The study is part of a larger TraDeRe research project funded by the Research Council of Finland and led by Associate Professor of Coaching Science Juha Ahtiainen (PI) in collaboration with Juha Hulmi (Co-PI). The data collection was carried out at the Faculty of Sport and Health Sciences, University of Jyväskylä, and proteomic analyses were conducted on 116 muscle samples at the University of Helsinki.