I will add this as it was late last night when i did he previous post and to relate to most points on this thread.
In the clip in the link
http://www.youtube.com/watch?v=mK-xNP9ysFE
notice my finger shape in relation to each other and the neck?
my fingers only lift off enough to allow the next finger to fret the string.
There is no excess lift away, because the further the fingers lift away from the strings the further the have to come back to them. So in being fluent they need to be close to the strings ready for use. As you can see me hand has its natural curl to it so for me the action is always a lifting action not a fretting action. Like most people, and that includes people that never play an instrument, i can fret a note, a single note....but unlike most of those who do not play, i can lift off the finger and replace it with another finger and fret another note.
If that finger does not get out the way then the note will not sound, if that finger gets sort of out the way and the other finger is in place the note will not sound. If the finger gets out the way and the other finger is not in place in time, the note will not sound.
What we need is the play a note, remove the finger and replace it with another in a clear path and the note will sound.
Well it will if the fretting hand can respond to the action of the plucking hand, again we see the need of the hands to work as a unit, so that means both hands to make the note and give the note quality of sound.
If another finger follows it down then let it do so, then lift that finger away if it is in the way, but only enough to be out the way.
Any finger movement is minimal so to see this and appreciate this curl your fingers in and hold them just off the palm. Now touch the palm with any finger.
Notice that the tips are all basically level so the touching process covers the same distance.
Notice where that movement is coming from, its not coming from the fingers as such but the joints, the joints control the action.
If i call the joints from the wrist 1-2-3, the first one is the big knuckle joint on the back of the hand the followed by the two smaller ones on the finger. The lifting action comes from joint no.2 if the fingers have the correct curl, if the fingers are to straight the the action comes from joint no.1 that big knuckle, so using more of the finger and therefore more of the attachments. Joint no.3 is the one that works with no.2 and that sets the angle of the finger tip to the action. have a look, a close look to what your fingers are actually doing.
Since the fingers share certain attachments that low in the palm of the hand base of the finger area, then certain functions in movement will be shared. If you hold you fingers straight you can move the tips off each one with enough movement to fret without the finger next to it getting in the way.
This movement come from joint no.2 and 3.
Joint no.1 only pulls it back... not lift it off, don't confuse the action of pulling back a finger out the way with that of lifting a finger off.
I see the fingers working as a unit but in both hands together, not just one and using both sides of the hand and forearm( the ulnar and radial) to achieve the movement me want in playing.
OK i have broken it up into a body mechanics thing, so understand it at its basic level and then use it. There is no deep hidden ideas in this, just use your hands better.
Bass guitar was never one of the tasks the hands were evolved to do, its a trade off we can do. So in that trade off understand what it is you need to make it work for you.
