So I've noticed, for the most part, that I can straighten any finger on my hand while keeping the adjacent one fully curled, creating a 90 degree angle between the extended and bent finger. All, that is, except for my ring and middle finger combination, which is sorely lacking in mobility.
While I assume this is natural, I can remember having a greater active flexibility in my fingers when I was younger. Passive flexibility is fine, as I can create the desired joint angle with use of an outside force, but I want to actively move my fingers into position.
When I attempt this, I can feel a very deep and strong contraction in the middle of my hands. For some reason, I feel that if I can perform this movement I will have a much greater grip strength.
I encourage you all to try this, and let me know what you think the reason is for the difficulty of the movement, and whether you think it is possible for me to accomplish it.
EDIT: If my description was vague, just imagine making a "pistol" with your hands, pointing the top two fingers, except with lower two fingers fully curled like a fist. Now try it the other way, with the bottom two fingers pointed.