Are there any historical facts about what specific piano exercises where taught by Fred Francois Chopin, Felix Mendelsohn and JS Bach (my favorite playing stars)? Have a book of good F Liszt exercises and J Brahms, wish tofind more advanced exs. as preparatory for an actual hardest piano pieces available in piano literature.
Well, for JS Bach it's easy. Start with the notebooks Klavierbüchlein für Wilhelm Friedemann Bach and Notebook for Anna Magdalena.
Also, look into the Well Tempered Clavier where several of the pieces had a pedagogical (teaching) purpose. Same for the 2 and 3 part inventions - the preface to those written by Bach makes clear they where teaching pieces.
For Chopin there are the etudes. But those aren't exercises per se. They are artistic pieces displaying various technical challenges on the piano.
I don't really know about Mendelssohn.
Something to keep in mind: before the Romantic era most teaching methods consisted of rudiments about reading music, very basic scale and chord examples, and then - importantly - a set of short keyboard pieces. In other words they didn't learn through exercises like Hanon, but through selected piano pieces. So, returning to Bach, your 'exercies' are largely a collection of minuets and other small dances, short preludes, and modest contrapuntal studies. You won't find drills like playing two octave scales in contrary motion in all keys, etc, etc.
Above and beyond any silly exercises people may employ to build strength, endurance, dexterity, blah, blah, blah is simple ergonomics and adherence to the laws of physics.
Bach played tracker organs. Go find one and try to play it. If you can't or find it difficult to play then, you probably either have a lot a flaws in your technique or have no idea what you are doing.
Key depression, whether on a tracker or Casio, comes first and foremost with the control of gravity or, the weight of the arm. Secondly, it comes from the in/out of the shoulder and elbow because your fingers are all different lengths. Third, it comes from the pronator and supinator muscles around your elbow. Fourth, it comes from your shoulder and elbow so you can place and realign the forearm so the weight of the forearm is behind each individual finger. Fifth, the arm places the fingers, the fingers don't drag the arms. With all the above, you will have the alignment so you don't twist the wrists in ulnar or radial deviation and power that you don't have to use the flexor muscles in the forearm (your fingers don't have muscles).
One of Bach's sons wrote a letter about his dad's technique stating that he played with effortlessness and with fire. This is because he played from the arm, not the poor little long flexor tendons which most pianists play from.
Do yourself a favor and go sit at a tracker. Call your local AGO chapter to find one. If you can't play it or you fatigue after five minutes, you've got some serious movement re-education to do.
You can't achieve technique through hours of repetition or silly exercises. Proper movement only comes from proper movement. Your arms have all the muscle they need to move your bones.
If walking barefoot on broken glass causes pain and bleeding, doing it for hours every day will not build strength and endurance. Technique can not be beaten into submission. Ergonomic movement and effortless playing is already within you. What most of us need to learn is how to get out of its way. Often, we don't need to practice more to achieve it, we need to find out what we are doing wrong that is hampering it. Like abducting our fingers and flexing at the same time or, employing a subtle adjustment of the elbow so the fingers are where they need to be and to facilitate the pulleys, rubber-bands and fulcrum of our arms.
Our arms are 1,000 times more fine tuned than a Swiss watch and that gives us way too much leeway to abuse those movements. Less is more. A subtle twist of the wrist can unravel thousands of hours of practice. Correcting a twist of the wrist is worth more than a lifetime of practicing Hanon.
My friend Chip had bad knees all his life. When he got old enough to have them replaced, his surgeon said "Your knees are fine, the problem is in your hips." He had both hips replaced. During PT, his therapist said "You have a shoulder problem." It turns out that as a youth he injured his shoulder and never had it looked at.
Do a sexy runway walk across the room (nobody is looking) and notice your shoulders and hips work opposite one another. Chip's right shoulder was locked with his right hip which caused strain in his knees. Try walking with your shoulders and hips locked together and you will feel a subtle strain in the knees. All your joints are designed to work opposite one another. Knotted tissues prevent this. Our arms are no different.
This is why gym class should be abolished and replaced with either ballet or Feldenkrais classes. Insurance companies would save a fortune.