Crofty wrote: ↑
Tue Oct 30, 2018 9:59 pm
Secondly I just cannot understand why people advise that m and a must move together.
Why? Do pianists and flautists have to move these fingers together? Do guitarists have to move their left hand 2nd and 3rd fingers together?? Clearly not.
The reason that doesn't happen is because it isn't physiologically necessary - and leaving that aside, if beginners are forced to move m and a together what on earth happens when they are then required to alternate those same two fingers?!!
As is typical for a brief video about a complex set of movements aimed at beginners, there are a lot of details that are left unsaid and some descriptions are less than clear or complete.
It is not that you are supposed to move 'a' with 'm' in the same forceful manner as the active finger 'm'; it is that you are not supposed to artificially freeze 'a' to stay (fully) extended while 'm' flexes, but rather to let it move as it wishes naturally as 'm' flexes. This is not explained in the video.
The reasoning behind this instruction, though, has to do with the physical limitations due to flexor tendon interconnections - the Quadriga effect. See this
which came up recently.
However, you can see how easy it is not to provide all the salient and clearest details so as not to overwhelm a beginner, say, which can then inadvertently create misunderstandings and misinterpretations.