The Role of the Right Arm in the Golf Downswing

Posted in Golf Biomechanics

The Role of the Right Arm in the Golf Downswing

In Golf Lag and the Compound Pendulum, we saw how power in the golf swing, in the form of club head speed, comes primarily from the correctly timed sequence of movements taking advantage of a simple mechanical phenomenon, the compound pendulum effect.

In this article, we take that discussion further by looking more closely at the role of the right arm in the golf downswing.

Once again, apologies to the lefties out there, but for simplicity these instructions are given for a right-handed golfer.

The right arm is often referred to by golf instructors as the “speed arm”, it has primary responsibility for transferring the energy from your torso through to the golf club, playing a crucial role in the golf swing kinematic sequence.

But the right arm isn’t simply used for energy transfer, it is also a compound pendulum in its own right, thus playing a complex role as a pendulum within a pendulum.

What’s more, the right arm amplifies the power generated by the torso as it transfers that power to the golf club.  The muscles in the arm and chest pulling and straightening the arm during the downswing, building more energy, and then releasing that energy into the golf club at precisely the correct moment for maximum club head speed through impact.

The timing of the movements of the right arm, and the timing of the application of force by the muscles within, and connected to, the right arm during the downswing, are crucial for a great golf swing.

Most amateurs use their upper body far too much and far too early in the golf swing.  This feels powerful, since your arms are connected to the golf club, but it prevents you from benefitting from the compound pendulum effect.  It throws away all of the club head lag that could be used to generate Tour-calibre club head speed if the golfer would only learn to back off and apply power with their right arm much later in the downswing.

If the muscles are fired too early, then the arm will straighten too soon.  This will disrupt the compound pendulum effect, resulting in a significant reduction in the energy that reaches the club head through impact.  It will cause momentum to be “thrown out” into the golf club too early, resulting in “casting” of the club and a dramatic loss of speed and accuracy.  Straightening the right elbow just 0.01 (one hundredth) of a second too early will result in a 10% loss of club head speed at impact.


Let’s take a look at how the right arm should move in the downswing:


Figure 1 - Tiger Woods right arm downswing sequence

Figure 1.  Tiger Woods’ right arm downswing sequence.


In Figure 1, we can see Tiger Woods’ downswing sequence, both from face on and down the line, in slow motion.  The blue lines and orange dots show the position of his right upper arm and forearm through the downswing.  The red arrows indicate where muscular force is being applied by his pectoral musclesThe pectoralis major is a very powerful muscle that forms the chest prominence. It moves the shoulder forwards and across your chest., deltoidsThe deltoid muscle is the the triangular muscle forming the rounded contour of the shoulder., tricepsThe triceps brachii muscle is the large muscle on the back of your upper arm, making up approximately two thirds of the muscle mass in the arm., subscapularis, latissimus dorsiThe latissimus dorsi (lats) is the widest and most powerful muscle of the back, and plays an important role in both the backswing and in powering the downswing., and teres majorThe teres major is an internal rotator and adductor of the upper arm and assists the latissimus dorsi in drawing the previously raised humerus downwards and backwards., pulling his right arm down and across in front of his chest, and straightening it coming into impact.

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