A New Understanding of How Muscles Work

Sarcomeres are the true powerhouses in your muscles and researchers now have a better understanding of how they work.

If you’ve never heard of sarcomeres, it’s because they’re very tiny—so tiny, in fact, that they are “the smallest unit within a muscle in which all the molecules responsible for making a muscle work can be found intact.” They are roughly 100 times smaller (in diameter) than the average human hair. According to the researchers, “there are between 2,000 and 2,500 sarcomeres found together in linked coils in each 10 millimeters of muscle fibre.” That’s very small!

However, they are the true force behind muscle contractions. Millions of sarcomeres work together every time you use your muscles. Muscle malfunctions could be the result of miscommunication between the tiny sarcomeres that make up your muscles. A new study from McGill University is the first to truly study these microscopic structures in order to analyze how they cooperate to make your muscles work.

To be able to study individual sarcomeres in action, the researchers used micro-fabricated needles to measure the force generated by the sarcomeres. They relied on high-tech microscopy to isolate and study the sarcomeres during contraction.

The results of the study were fascinating. The researchers found that when just one sarcomere activated, all the surrounding sarcomeres adjusted to the activation. The muscles are essentially massive cooperating chains of sarcomeres, and it’s only through precise cooperation that our muscles are able to work.

Which, of course, led the scientists to a clearer understanding of what causes muscle failure and malfunction—both simple muscle problems (like post-workout muscle failure) and more complex disorders (such as muscular dystrophy or even heart failure). By breaking down muscle function into this tiny cellular structure, the researchers are able to delve deeper into the miscommunications and malfunctions among the sarcomeres that lead to all types of muscle malfunctions.

According to the lead researcher, “The technique opens many possibilities in the muscle field.” Not only does this information provide greater insight into how all the muscles in the body function, but also into the causes of muscle malfunctions. Once the causes are understood, there is potential for treatment and prevention.

What does the future hold? Unlimited possibilities, according to the researchers! “Our next step is to look into what happens in heart failure and other diseases of the muscular system when sarcomeres fail to cooperate.”


1. Felipe de Souza Leite, Fabio C. Minozzo, David Altman, Dilson E. Rassier. Proceedings of the National Academy of Sciences, 2017; 114 (33): 8794 DOI: 10.1073/pnas.1700615114