Experience Better Golf

“External Shoulder Rotation”

The Secret to Shallowing the Club

The Biomechanics: External vs. Internal Rotation The shoulder is the most mobile joint in the human body. In the golf swing, we specifically test the "90/90" position (arm abducted to 90 degrees, elbow bent to 90 degrees) to measure rotation.

During the backswing, your trail shoulder must have extreme External Rotation (the ability to rotate the back of your hand backward). If the shoulder joint is tight, the arm cannot lay back. This forces the trail elbow to flare wildly up and out (the "Flying Trail Elbow"), completely altering the plane of the golf club.

The Golf Connection: The Domino Effect A lack of external rotation in the trail arm is the primary physical cause of a steep downswing:

  • [Link: Over the Top]: If your trail shoulder cannot externally rotate, the club shaft gets incredibly steep at the top. The only way down to the ball is outward and over the top.

  • [Link: The Chicken Wing]: If the lead shoulder lacks internal rotation through impact, the arm physically cannot fold naturally, forcing the elbow to pull up and out.

  • [Link: Casting]: Without external rotation to "shallow" the club, you cannot hold lag. You must throw the clubhead early to square the face.

The Self-Screen: The 90/90 Test

Test your shoulder capsules' rotational limits.

  1. The Setup: Stand tall in your normal posture. Raise your right arm straight out to the side until it is level with your shoulder. Bend your elbow to 90 degrees so your fingers point straight up to the sky (like you are swearing an oath).

  2. The Test: Keeping your elbow exactly where it is, try to rotate your hand backward (External Rotation) as far as it will go. Then, rotate your hand forward and down toward the floor (Internal Rotation). Do not let your spine bend backward to cheat the motion.

  • ✅ PASS: You can rotate your forearm backward past the line of your spine (greater than 90 degrees) and rotate it forward past the plane of your chest without your back arching or your elbow dropping.

  • ❌ FAIL: Your hand stops moving straight up, or you have to severely arch your lower back to get the hand to move backward.

The Protocol: Oiling the Shoulder Joint

If you failed, your pecs (chest muscles) are likely pulling your shoulders forward, locking the joint.

1. The Doorway Pec Stretch

  • Setup: Stand in a doorway. Raise your right arm into the 90/90 position and place your forearm/palm flat against the doorframe.

  • The Action: Gently step forward with your right foot until you feel a deep stretch across your chest and the front of your shoulder.

  • The Breathing Protocol: Lean in until you feel restriction. Exhale slowly and deeply, using the breath to tell the chest muscle to stop fighting the stretch. Lean an inch further on the empty lungs.

  • Reps: Hold for 45 seconds per side.

2. Active Lying 90/90 Rotations

  • Setup: Lie flat on your back. Bring both arms into the 90/90 position on the floor (backs of your hands touching the ground near your ears).

  • The Action: Slowly rotate your hands forward, trying to touch your palms to the floor near your hips without letting your elbows lift off the ground.

  • The Breathing Protocol: Inhale as your hands go back. Exhale steadily as you rotate your hands forward toward the floor.

  • Reps: 15 slow, continuous rotations.