Asked by: Simon Taylor, London
There are two kinds, both very real. The first, properly called ‘procedural memory’ strengthens the synaptic pathways in your brain for specific coordinated sequences of muscle movements that you perform often. This is what allows a guitar player to form the chord shapes without consciously considering the position of each finger, for example.
There is another kind of muscle memory though. If you have previously put on muscle mass through training, then it is easier to bulk up again in the future than if you had never trained before. Muscle cells gain extra nuclei during training and these can last for 15 years, even after the muscle fibres have shrunk back to normal size. It is as if the muscles ‘remember’ their previous strength and find it easier to return to that level.