The Abdominal, needs to be in optimal condition state, when playing good quality golf.
The Abdominal lead and the hands follow. Look at Tigers swing and you will see a good example of the Abdominal leading and the hands following.
 
1. Abdominal- conditioning the abdominal includes all the basic sit up and the variations .
BASIC- lying on your back ( with you heels close to your bottom)and lifting your head off the floor, arms by your side.
INTERMEDIATE- as above, with your arms crossed in front of your chest
ADVANCED- with you arms extended above your head.