In Playing With Fire #4 I mentioned
dropping the hand or finger into the key. This is called playing
with gravity or arm weight. Some pianists may complain that certain
pianos have a stiff action or, when they are cold, they have
difficulty depressing keys. That is because they are trying to use
the flexor muscles or the non-existent finger muscles to play. Your
fingers have no muscles. They are moved by the muscles of the
forearm.
When a pianist plays with gravity, the
keys go down effortlessly because they are not using any muscle to
depress the key, they are only using gravity or the weight of the
arm. The only muscle engaged is the bicep which raises the hand from
the fulcrum of the elbow, then controls the descent.
It is important to note that once your
finger depresses a key, after you hit the "point of sound,"
you unweigh your arm so that you are not pressing down, leaving just
enough weight to keep the key down. Another source of the apocryphal
"repetitive strain injury" is pressing into keys because
pressing stretches the long flexor tendons and stretching can create
strain and micro tears. Since tendons do not have an active blood
supply to promote healing, the body places scar tissue in the wound
but, scar tissue does not stretch and results in larger tears the
next time you stretch.
Warming up through stretching is also a
myth. What happens when you overstretch your muscles, you tear
muscle fibers and the body rushes blood to the site to begin
repairing the damage of the stretch. Since blood is warm, it gives
the illusion of warming up. A better way to warm up is to sit in a
warm room. Also, you can't spot warm up since your blood is always
circulating. When muscles and tendons are actually cold, they
contract and resist stretching. Stretching cold tendons is always
bad because they are contracted, resisting stretching and more apt to
tear than stretch.
It is sort of like stretching warm
taffy into gooey strands. Try that with frozen taffy and it will
break. It is important for a pianist to never play with a cold body
unless you have mastered ergonomic playing and the laws of physics.