Is Muscle Memory a Myth? Interview with:

Maléne Lindholm, PhD Karolinska Institutet Dept. of Physiology & Pharmacology Stockholm Sweden

Dr. Maléne Lindholm

Maléne Lindholm, PhD
Karolinska Institutet
Dept. of Physiology & Pharmacology
Stockholm Sweden What is the background for this study?

Response: It is well known that exercise training provides marked health benefits and can prevent and treat a broad set of diseases. Therefore, a deeper understanding and characterization of the molecular processes behind training adaptation is essential for human health.

This study aimed at exploring the effects of endurance training on the human skeletal muscle transcriptome (activity of all genes) and investigate the possible presence of a muscle memory of training. To do this, the healthy volunteers in this study first trained only one leg, 4 times per week for 3 months. After 9 months of detraining, the subjects then came back and trained both legs in the same way as during the first training period, thus one leg was then previously well-trained and one previously untrained. This meant that each individual was their own control, as both legs have the same genome, experience the same stress, diet etc. Only the training status differed. What are the main findings?

Response: Training changed the activity of 3400 RNA variants (isoforms), associated with 2600 different genes, as well as transcription of novel, functionally unknown RNAs. Analyzing gene activity at this level even showed that training altered the same gene to increase the production of one RNA variant and reduce that of another, which means that genes can change function as a result of exercise and, for example, start to promote the production of certain protein variants over others. With regards to muscle memory, there were no clear residual effects of previous training after 9 months of detraining. However, the repeated response to training was somewhat different in the trained and previously untrained legs in the second training period, which suggests that the exercise could have left other lasting impacts. What should readers take away from your report?

Response: Our work not only provides a broad and robust knowledge as basis for future studies on muscle biology and training effects but also opens up questions on unexplored parts of the human transcriptome with the discovery of numerous training-induced novel transcripts. Although there was not enough evidence to claim the presence of a human skeletal muscle memory of training, there is a surprising variability in training response within individuals and residual memory effects of training can not be excluded. This work is highly relevant from a healthcare perspective as the mechanisms behind training-induced health benefits and how to optimize training effects are very important in society today.

That a lifestyle change known to reduce morbidity and mortality in patients with e.g. cardiovascular disease and type II diabetes was shown to induce specific transcriptomic changes is also highly interesting from a drug target identification perspective. What recommendations do you have for future research as a result of this study?

Response: This first, pioneering study on human skeletal muscle training memory provides a great basis for further studies on this intriguing question of human biology. The large transcriptome dataset will hopefully inspire deeper molecular investigations and follow-up studies. The role of the novel transcripts in training adaptation is also of great interest for the understanding of how humans adapt to endurance training, and further investigation of the function of these transcripts is very important. Thank you for your contribution to the community.


The Impact of Endurance Training on Human Skeletal Muscle Memory, Global Isoform Expresssion and Isoform Transcripts

Maléne E Lindholm ,Stefania Giacomello ,Beata Werne Solnestam,Helene Fischer,Mikael Huss,Sanela Kjellqvist ,Carl Johan Sundberg

 PLOS Published: September 22, 2016

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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Last Updated on September 26, 2016 by Marie Benz MD FAAD