To list all the muscles used in the full range of piano playing I would need to list all the muscles in the body (As Richter once said “ I played that note with my big toe!”)
And since Monk disagrees, perhaps a more useful question is, “what muscles are those that are atrophied in the normal person, and that need to be developed for piano playing?”
First let me say that although I believe Monk is wrong when he says that all muscles have the necessary strength to start with (I will get there in a moment), he is absolutely right in everything else he says. Ultimately it is not a matter of strength, but of co-ordination. However even for co-ordination you will need a minimum of muscle development. Muscle takes 3 – 6 months to grow. After that all the work becomes nervous and ceases to be muscular. The best way to develop these muscles is simply by playing (correctly) the piano.
Secondly, since the advent of the computer and its widespread use, many of the muscles that were once atrophied are no more simply because of typing in a computer keyboard.
Thirdly have a look here just for the muscles in the hand and forearm (you use far more muscles than these, but these are the ones most likely to be atrophied in the normal person since you do not use them regularly enough as we will see later.):
Muscles in the hand:
There are three main groups of muscles in the hand: The thumb muscles (radial) the little finger muscles (Ulnar muscles) and the palm muscles (which occupy the spaces between the bones – and therefore called interosseus – and the lumbricales muscles). All these muscles are in the hand, not in the fingers – which only have tendons).
Radial (thumb) muscles:
1. Abductor Pollicis
2. Opponens Pollicis (Flexor Ossis metacarpi)
3. Flexor Brevis Pollicis
4. Adductor Pollicis
Ulnar (little finger) muscles:
1. Palmaris brevis
2. Abductor Minimi Digiti
3. Flexor brevis minimi digiti
4. Opponens Minimi digiti (Flexor Ossis metacarpi)
Palm (middle of the hand) muscles:
1. Lumbricales (there are 4 lumbricalis muscles)
2. Interossei palmares (there are 3 of these, on top of the metacarpal bones). These muscles adduct (move towards) the fingers towards the middle finger.
3. Interossei dorsalis (there are 4 of those, in between the bones – metacarpi – of the hand: Abductor indicis) these muscles abduct (move away) the fingers from the middle finger.
Both palmares and dorsalis interossei can help flex the fingers if they are already flexed.
These muscles are so little used in the average person that they need to be developed and strengthened. Anatomical fact: Size and number of lumbrical muscles vary from person to person. Some people do not even have lumbrical muscles. If so, a career as a piano super-virtuoso is out of question. (But you can still play the piano).
Muscles of the forearm.
Anterior brachial region:
Superficial layer.
1. Pronator radii teres
2. Flexor carpi radialis
3. Palmaris longus
4. Flexor carpi ulnaris
5. Flexor sublimis digitorum
Deep layer.
1. Flexor profundus digitorum.
2. Flexor longus pollicis
3. Pronatur quadratus
Radial region..
1. Supinator longus
2. Extensor carpi radialis longior
3. Extensor carpi radialis brevior
Posterior brachial region.
1. Extensor communis digitorum
2. Extensor minimi digiti
3. Extensor carpis ulnari
4. Anconeus
Deep layer.
1. Supinator brevis
2. Extensor ossis metacarpi pollicis
3. Extensor primi internodi pollicis
4. Extensor secundi internodi pollicis
5. Extensor indicis.
Understand this, because there are deep consequences for how you are going to go about it: We cannot consciously move any particular muscle. All we can do is to will a particular motion of the hand. Therefore, in order to have a specific muscle to contract, one must discover which peculiar movement of the hand will use that and only that muscle.
As babies and toddlers we do not learn how to contract muscles, we learn how to move and most of the time we do not really care which muscles we are using. So it is perfectly possible for two different persons to achieve a certain complex motion by using completely different sets of muscles. Once the habit is ingrained, and the motion becomes usual, the muscles not used will atrophy, while the muscles in use will be strong and developed. So two different persons performing the same motions may have different sets of muscles atrophied and developed.
Have you ever tried eating with chopsticks? People who have been eating with forks and knives all their lives do not have the muscles necessary to eat with chopsticks fully developed simply because they are not used in their daily lives. The way to develop them is to eat with chopsticks regularly. The problem is, because their “fork muscles” are well developed; they tend to use those muscles (and co-ordinations) even though they are clearly inappropriate. You can see them at Chinese and Japanese restaurants. They are eating with chopsticks, as if it was their native eating implements. They think they have mastered it – and to a certain extent they manage to get the food to their mouths. But to an expert chopstick holder, they are doing it all wrong. They hold the chopsticks to near the middle, not at the extremity. The chopsticks are not in the same plane and therefore they frequently cross over each other. They hold them parallel and too close together, which stops them from actually being able to pick pieces of food. So for some three months they have to get expert tuition, someone who knows and can actually show them the motions and the way to hold the chopsticks, and they must persist on them no matter how clumsy they may feel,
because it is from repeating the appropriate motions that he correct muscles will grow. Then after this phase, comes nerve control and co-ordination (in fact they will be there from the beginning, but it is only after the muscle is developed enough to respond that they can be fully operational).
More often than not, the set of muscles you use for a certain motion will not be indifferent: There will always be a configuration that is more efficient for a specific motion. This ultimately explains why some people excel at certain motions while others never rise above the mediocre. Excelling people are using best muscle configurations and co-ordinations, having arrived there either by chance or by careful guidance from those in the know.
Just to give you an example (there are plenty more), in order to play an octave (if you have small hands),or anything bigger than a tenth (if you have big hands) you will need to use the interossei muscles in the hand. A person who does not need to use this movement (and most people don’t) will have these muscles atrophied from lack of use, since most normal daily activities do not require the use of these muscles. They will need to gradually work them up to a point where they can play octaves/tenths. If you are a beginner, or if you have not played many octaves before, to jump straight into some piece/study that requires extensive use of octaves is to court injury. You can usually spot pianists by looking at the outside edge of their hands just below the fifth finger. The palm there is thicker than a non-pianist. You can see it in videos of , for instance, Alicia de La Rocha, who had very small hands, and therefore a very developed interosseus.
As you can see, the best way to learn/teach this stuff is not by reading/writing about it. You need a hands on approach. Either you find someone knowledgeable to show you and to make sure you are not doing the wrong thing (surprisingly easy to go wrong, even with someone knowledgeable watching over you) or you embark on program of systematic and careful experimentation (this is basically what super-slow practice – 5 seconds on each key – is all about: trying to isolate muscles through specific motion).
In any case, here are the three commandments:
1. Do not make unnecessary movements or muscle contractions.
2. Do the necessary movements as smoothly as possible.
3. If you have a choice, always use the strongest muscles that will perform the motion.
I suggest you get a book of Anatomy (or have a look at some of the medical anatomical sites in the net. Some even have animations showing which muscle does which movement. Here are some:
https://www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/dissector/mml/mmlregn.htmhttps://www.eatonhand.com/hom/hom033.htmhttps://moon.ouhsc.edu/gsharp/namics/hand.htm#muscles).
Also have a look at posts from xvimbi and Robert Henry. They often talk about this subject and offer valuable advice.
Best wishes,
Bernhard.