Hi,
do you know:
as soon as the ball leaves the hand/foot there is about no accelertion measurable inside the ball (free fall, no G).
You can only measure the negative acceleration caused by air. Without air you will measure zero speed and zero acceleration.
If you want to measure speed you need one ore more external (out of the ball) point to refer to. (GPS for example)
What you can do is to measure accleleration and with that (after the ball leaves the hand) the only thing you can do is to calculate its speed taking the known/fixed acceleration of the earth into account (9.81m/s^2).
Klaus