This
is a wonderful question. There is no such thing, literally, as muscle
memory. Movement is hardwired into the brain, not the muscles.
New
muscle memory movement is very easy to wire into the brain and it can be immediate however, the
brain never forgets the old patterns so, as a musician, if you get
nervous or your body is cold, or you go into autopilot, it is very easy
for the old movements to reassert themselves and take over despite new and
more efficient neural pathways having been created since. This is especially true for
musicians and also, how and what we play is very important. This is why
musicians often claim they can play perfectly in their living room but
on stage it all falls apart. What is happening is the old muscle memory
takes over because of environmental factors such as the presence of an audience, different bench height, temperature, nerves, etcetera.
There
is another danger here. Many teachers instruct the student to build
strength and endurance to overcome technical deficiencies. This works to
a certain extent but also puts the musician on the path to injury. If the
musician then learns new and proper movements, the improper muscles used
previously will immediately atrophy. This is why improperly trained
musicians feel rusty or stiff after missing a few days of practice
because the wrongly built muscles will get weak, quickly. Proper playing
utilizes fulcrums, alignment, gravity, ergonomics and the laws of
physics, not muscle. This is counter intuitive to most musicians and
to many teachers who are ignorant of anatomy and physics. Mediocrity is the
result of using the wrong muscles, not lack of talent. This is because
most teachers have no idea what they are doing. They only know what they
know but what they don’t know is what creates injury, tension, fatigue
and sloppy playing.
A
beginning student may learn a piece of music and there may be flaws in
his movement. Over time he gets better and learns new songs and rewires
some of the improper movements in his brain. He progresses further and
his technique improves and his brain learns newer and even more proper
movement. THE DANGER is playing old repertoire because even though his
technique improves and he now has proper movements, the brain remembers
the lesser or improper movements of previous repertoire from a time when he moved
less properly. It is important for musicians to either never play old
repertoire or, re-learn each piece with the newer, more proper motions.
The
greatest danger is, as I previously said, the improper muscles atrophy
if not used. If a musician built improper muscles to play a piece well,
then as he progresses and loses that muscle because it is no longer
needed since he is more ergonomic now, then he plays that old
repertoire, the brain expects that the former muscle is there and tries
to play the work “normally.” Since the muscle is no longer present, this
is when the musician runs the risk of greatly injuring themselves. This
is why a well trained musician can one day, out of nowhere, injure
themselves. Most injuries are actually cumulative and it is one of those "muscle memory" moments that serves as the proverbial "straw that breaks the camel's back."
In
addition, rewiring your brain on your instrument isn’t sufficient. You
must simultaneously do the same with how you ring a doorbell, tie your
shoes, brush your teeth, pick up a piece of paper, type, swipe, wipe . .
.
There is no such thing as repetitive strain, only improper movement. If you move improperly, all movement can become repetitive strain and as I said, it is cumulative. That is why a forty year old might get out of bed with stiffness, aches and pains while a 70 who has moved properly all their lives can rise with elan and alacrity. You can take that to the movement bank.