Good abdominal muscle group tone protects the spine and promotes good coil and recoil, thus producing power in the golf swing.
If you work these muscles in harmony with the lower-back muscles (latissimus dorsi and the glutei muscles), you will succeed in rotating just above the pelvis and maintain good lower-body stability in the swing. This will also result in more power being generated through the lumbar pelvic area.
The majority of golfers who play intensively have tight hip flexors. Prior to carrying out abdominal exercises, golfers should stretch their hip flexors to ensure these muscles are not used instead of the abdominals. These muscles also help to maintain good spinal angle throughout the golf swing. Dysfunction in this area will result in a reverse pivot and, possibly, a sheering or jamming of your back at impact.