Golf Swing - Muscle Activity Analysis
This page is dedicated to providing research based information regarding the golf swing and the main muscles that are used during each phase. For proper understanding, the swing will be broken into specific phases: back swing, forward swing, acceleration, early follow through and late follow through.
The back swing is ball address to top of back swing. Forward swing is the top of swing to club horizontal (early part of down swing). Acceleration is horizontal club to impact (late part of down swing). Early follow through is impact to horizontal club. Finally, late follow through is horizontal club to completion of swing. 
The swing analysis will be in reference of a right handed golf swing.
Back Swing - During this phase the most active muscles in the upper body are the upper trapezius and middle trapezius on the right side. On the left side, the most active muscles were the subscapularis and the serratus anterior. This means that the mid and upper back are very active on the right side and one of the rotator cuff muscles is really firing on the left. In the right leg, the hamstrings are very active and on the left side, the erector spinae (back extensors) and abdominal obliques are contracting the most.
Forward Swing - The pectoralis major is the main muscle at use on the right side here, followed by the serratus anterior. On the left side, the mid back is working the most with the middle trapezius and rhomboid being the most active muscles. In the lower extremity, the right gluteus maximus is the most active followed by the hamstings. On the left side, the vastus lateralis (part of the quads) and the inner thigh are used to most.
Acceleration - The pectoralis major muscle is the most active on both sides during this phase. The right abdominal obliques are very active along the the gluteus medius. On the left, the lateral hamstings along the the gluteus maximus are the most active.
Early Follow Through - In the phase of the golf swing, the pectoralis major muscles are the most active on both sides. The second most active muscles are the subscapularis on the right and infraspinatus muscles on the left (the subscapularis and infraspinatus are both rotator cuff muscles). The gluteus medius and obliques are still firing on the right, along with the the outer quads and hamstrings on the left.
Late Follow Through - As the club decelerates, the right subscapularis is the most active followed by the both the upper and lower serratus. On the left, the infraspinatus and pec major are working the most. In the lower body, the right lateral quad and gluteus medius are firing the most, and on the left, its the inner hamstring and thigh followed by the lateral quads that are contributing the most.
The information contained on this page is from a review of the literature regarding the golf swing and muscle activity.
1. A McHardy, H Pollard. Muscle activity during the golf swing. Br J Sports Med 2005;39:799–804.
Click here to read the full article