The term "muscle memory" is a misnomer (though a good descriptor for how we experience it). As I recall, it largely involves reinforced pathways (multiple connections for the same path), and myelination (insulative sheathing for the neuron). The more you use a pathway, the more connections the neurons make, and the more myelin is added. Well-traveled pathways become more efficient and easier to use.Is muscle memory in that equation somewhere?