It’s not uncommon to flip through a golf magazine and spot an article on the importance of core strength for hitting the long ball. Although strong core leads to increased power and distance, the benefits during your swing are far greater than bragging rights in the long drive competition. Sure, you’ll generate more club head speed, but that’s meaningless if you can’t golf without pain. Our core muscles stabilize the spine during the back, acceleration, deceleration phase of swinging. Your core muscles are more than the superficial abdominal muscles known as the rectus abdominus or the “6 pack.” In fact, your rectus abdominis has very little to do with a golf swing. Our deeper and lesser known core muscles are responsible for dropping a bomb off the tee. These multiple layers of muscles wrap the trunk and coil during our back swing to unleash torque down the club shaft and into the ball.
Most EMG(electromyography) studies, which measure muscle activity, show significant muscle activation of the deep abdominal muscles (internal obliques, external obliques, multifidus and transversus abdominus), while actually omitting the rectus abdominus. What does this tell us? That training our rectus abdominis, usually done with crunches and sit-ups, will be a waste of time. In fact, contraction or excessive activation of the rectus abdominus near impact will flex the trunk bringing the upper body and the head closer to the ground leading to inconsistent and “fat” ball striking. The deeper layered obliques and transversus abdominus/multifidus are the main rotators and stabilizers of the spine/trunk. Purely based on muscle fiber orientation for a right handed golfer the right external obliques have high activation during the backswing to initial downswing and the left internal obliques become more active in turning the trunk down and through during impact to follow through.

The image above shows the superficial muscles of the abdominal cavity. The black arrows represent the line of pull for the external obliques and the rectus abdominis. The internal obliques (not shown) also produces large amounts of rotational power. The deeper muscles (multifidi and transverse abdominis) stabilize the spine through your swing.
Activation and timing of your obliques during your swing assists in generating large rotational force through the trunk, into the shoulder, down the arms, and descends the shaft into the club head, increasing club head speed and ultimately more distance on the course.
The multifidus and the transversus abdominus, which are the deepest layer of abdominal muscles, are vitally important during the golf swing. Unlike the oblique muscles, the multifidi and transverse abdominis muscles play a vital role in spinal stabilization–not torque production. These muscles wrap and attach to boney contours of the spine and activate during the downswing to impact points, limiting the amount of load or shearing forces on the spine.1 Research shows that delay in tranversus abdominus activation during a golf swing was a consistent factor in golfer’s with chronic low back pain. 2 This grouping of muscles can be trained by simple exercises including pelvic setting and planking. These core strength exercises assist in maintaining a neutral spine and avoiding a flexed spine at impact.
The goal here is to increase your distance while reducing your risk for injury, particularly to the low back. Activation of the deep core muscles will assist in stabilization through your swing, while the obliques produce torque through the trunk and spine to increase club head speed. Foregoing the typical crunches at the gym will only benefit you, not only to preserve your low back but to also help you reach your fullest potential and hit the long ball.
References
1.)Hodges PW, Richardson CA. Inefficient muscular stabilization of the lumbar spine associated with low back pain: a motor control evaluation of transversus abdominis. Spine 1996;21(22):2640–50.
2.) Richardson CA, Snijders CJ, Hides JA, Damen L, Pas MS, Storm J. The relations between the transversus abdominis muscles, sacroiliac joint mechanics, and low back pain. Spine 2002;27(4):399–405.