Clarification for "proper" finger strokes

[bearzinthehood]

I've been thinking about finger strokes, and finger strength.  In general (and perhaps this is a bit of a simplification), there seem to be two main types of finger strokes.  Finger strokes that originate from bending at the knuckle, and finger strokes that originate from bending (pulling) at the last (nail) joint.  Now from my understanding, the former movement uses muscles inside the hand, and the latter movement uses muscles in the forearm.  The two conflicting viewpoints that I have seen on this matter are as follows:

1)  The muscles in the hand are intrinsically weaker.  It is better for fingers to pull at the nail joint because this type of stroke is stronger and guarantees proper joint alignment in the fingers.

2)  The use of muscles in the forearm causes the wrist to tighten up, it is better to bend at the knuckle in order to prevent a stiff wrist and in order to prevent tendonitis, CTS, etc.

Now I am of the opinion that the first viewpoint is correct.  The stiff wrist and carpal tunnel issues, IMO, are resolved by correctly aligning each finger with the corresponding flexor in the forearm before using any finger stroke.  This is proper alignment is stressed by Sandor and by every single piano teacher I've ever had a lesson with.  Furthermore, bending at the knuckle only and relaxing everything else causes collaped joints in the finger, which further reduce the power and control of each stroke.  Still, I am neither a doctor nor a professional pedagogue, and there are factors that complicate this issue.

- There are situations when exactly perfect alignment is not possible, some popular examples on this board seem to be the Chopin etudes in A minor Op. 10 and G# minor Op. 25.  In these situations if we use the forearm muscles it becomes unavoidable that an inefficient finger stroke occur.  Can this lead to injury?  I have no idea...

- Another complication is the release.  As I'm sure you're all well aware, the 4th finger cannot rise independently at the knuckle joint.  It can, however, rise independently at the joints in the finger.  If an independent (or mostly independent) release is required, such as in a 3-4 trill, which stroke will lead to the most effortless, least damaging, and above all best sounding release?

Perhaps some of the more knowledgeable members of this forum can help me out on this, because I not entirely clear on this issue. 

[rimv2]

Playing from the knuckle is usually more solid. A lot of people believe they are playing from the knuckle when they are not. They lift the finger at the knuckle but bring the finger down using the tip. That's all ah have to say about that.

Best wishes,

Karrim