The Biology of Muscle Memory

Exploring Neural and Muscle-based Mechanisms

Abstract

The phenomenon known as muscle memory is a result of a diverse number of highly complex biological systems. Two notable biological systems contributing to muscle memory are the muscular system and the neuronal system. 

It is hypothesized that the myonuclei within muscle cells allow the muscle cell itself to retain a ‘memory’. However, the concept of memory in the musculoskeletal system is divergent from the hypotheses of memory in the central nervous system. For example, an increase in nuclear content within a muscle cell (i.e. myonuclear content) results in the muscle cell getting stronger faster compared to a muscle cell with less myonuclei. Increased activity causes a muscle cell to produce more myonuclei, which even after detraining stays within the muscle cell for a period of time. Thus, if a person detrains after doing previous training, when they retrain again, their muscles will be more receptive to the training and become stronger at a quicker rate compared to before the initial training.

Neurons, specifically the amount of acetylcholine receptors (AChR) present at the neuromuscular junction (NMJ), is thought to play a role in the underlying mechanisms of developing muscle memory. This is because in rodent preclinical trials there is a positive correlation with the amount of AChR present in the neuromuscular junction and the amount that the muscle is exercised.  However, it's important to note that divergent results have been seen in human clinical trials due to multiple factors that will be discussed in this paper. Understanding the conditional mechanisms responsible for muscle memory is beneficial to many groups of people, including the average person, athletes, and people with neuromuscular disorders.