I have read that the flexion towards the back of the hand is used to cement the overall direction and feeling that the fingers should take, but when playing that accentuated movement is obviously reduced otherwise you would not get up to speed.guit-box wrote: ↑Mon Aug 21, 2017 1:05 amI do not know, perhaps for some people the MCP extending is a consequence of a large follow-through of PIP/DIP. (ie it just happens for them) or maybe it's just relaxing or maybe it's intentional extending. The point is that if a joint finger is moving it's corresponding finger phalange away from the hand, it is extending, that's the definition of extension.
Probably the more important point is this: If we see the MCP extending at the moment the string is being sounded, then it can't under any circumstances also be in flexion at that moment. But most every modern method book or video tells us to follow through from the MCP or use lots of "swing space". Clearly then this is incorrect since no one (including the people teaching this) actually does this when they play.
My view is that you are not seeing deliberate extension but rather you are seeing an ultra relaxed release of tension at speed and the extension is a natural consequence of moving to pluck the next note. It's what I would call skill - gained through a combination of natural ability and hard graft. To me the ability to discharge tension immediately after plucking seems obvious but not someasy to achieve.
I have had lessons off people who had me going into the palm of my hand but they were quick to point out that you don't actually play like this. I agree though that many teachers don't explain themselves.