When I began to play the sax I discovered how weak my fourth fingers were.
If I rested my wrist on the table with my finger tips touching the table. I found that I could drum quite nicely with my thumbs (1) index (2) and middle fingers (3) even my pinky (5) had some control, but my fourth (4) fingers had no movement at all. Sure I could curl them inwards with some force, but I couldn’t lift them above the table’s surface at all!
I have been practicing lifting and dropping my fingers to drum on the table with various patterns like 1,2,3,4,5 and 1,3,2,4,5 etc. and now I can raise them (4) about 10mm. Having precise control of the individual fingers is imperative to playing fast and accurately. You will notice that when trying to move these fourth (4) fingers, adjacent fingers will also move with them. The trick is to practice so that individual fingers only move when you want them to.
This form of practice can be done anytime during the day. All one requires is a flat surface to rest your wrist on.
You will see that your hands fatigue quite quickly in the beginning.