do a fit buddy search at the bottom of the screen for your abs answers.
It has been answered one million times.
Shotput - core musculature, shoulder, triceps, legs for balnce and stability..ummm, pretty much your whole body needs to be worked. There may have been a previous post in the powerlifter's forum, try a fitbuddy search.
Do you have a coach - they may have a specific conditioning program for you.
Dynamic movements with exercise band that mimic how you move when throwing the shot might be a good start.
-------------- An old thought for the New Year - \'If you fall down seven times, get up eight\'
What matters is that you continue on.