Muscle activity during the golf swing (P1)
Golf is a popular recreational past time in Australia and throughout the world.golf swing is a complex movement. The involving the whole body and is used to develop momentum that is transferred to the golf ball to propel it towards the target. This movement pattern requires a coordinated sequence of muscle activity to efficiently transfer the power generated by the swing. The purpose of this research is to review the muscle activity that occurs during the golf swing. This paper presents a review of the synergistic action of the muscles of the upper and lower body during the golf swing and discusses how these muscles are recruited during the different swing phases. For the purpose of this paper, all swing related activity refers to a right handed golf swing unless otherwise noted. By understanding the component parts of the golf swing, the clinician may be able to better construct a sports specific management programme. Such a management programme could target specific muscles and actions to improve function and reduce injury producing mechanics.
A Medline search was conducted on studies carried out between 1965 and the present. The key words golf, swing, and electromyographic were used. A hand search of references in selected papers and Science and golf: proceedings of the World Scientific Congress of Golf books were also reviewed. Research papers that fit the criterion of being an electromyographic (EMG) analysis of the golf swing were reviewed, and the data collated were used to provide an overview of the muscle activity that occurs throughout the body during the golf swing.
There were studies that fitted the Medline search criteria, with an additional three studies found in Science and golf: proceedings of the World Scientific Congress of Golf (table 1).
Most of the literature has focused on the EMG analysis of the shoulder and lower back. Very little research has been conducted on the forearm and lower limb during the golf swing, and one study compared expert and novice differences in muscle activity during the golf swing. However, the latter paper merely reported that there was larger variation in muscle activity in the novice golfers than the expert golfers, with no data on muscle activity reported. The injury literature has determined that the lower back, wrist, and elbow are the three most common sites of golf related injury. Although there is EMG analysis of back muscle activity, only one paper has investigated muscle activity of common forearm and wrist injury sites.
A number of papers have investigated the function of the shoulder muscles during the golf swing. Research at the Kerlan Jobe Orthopaedic Clinic, Los Angeles, California collected data from different golfer groups. Male professional golfers were the subjects in one study. The data were then reported again on sequential occasions after the addition of subjects/groups (women, amateurs) to the data set and after advances in technology. The final paper by Pink et al reports on the combined data, which are used in this review. Studies performed by Kao et al and Jobe et al analysed scapular and rotator cuff function during the golf swing. The activity of the trunk activity, both anterior and posterior, the lower limbs, and the forearm during the golf swing have been the focus of other separate studies.
In total, muscle groups were investigated in the nine papers analysed. A number of the muscles were divided into upper and lower or anterior, middle, and posterior sections. Table 2 summarises the muscles selected for EMG analysis.
Many of the trunk/axial muscle groups and the proximal appendicular muscles have been evaluated during the golf swing and are reported in table 2.
The studies generally break down the golf swing into the following five phases (fig 1):
- Back swing: ball address to top of back swing
- Forward swing: top of swing to club horizontal (early part of down swing)
- Acceleration: horizontal club to impact (late part of down swing)
- Early follow through: impact to horizontal club
- Late follow through: horizontal to completion of swing
Either the Basmajian single needle technique or surface electrodes were used to collect muscle activity data. Before conduction of the golf swings, a peak one second EMG signal during manual muscle strength testing (MMT) was selected as a normalising value (100%) for each muscle tested. Tables 3 and 4 summarise the results of most active muscles in the upper and lower body respectively.
Backswing ( intheright handed golfer )
The back swing starts from the time the club starts movement to the top of the back swing. During the backswing, the most active muscle in the upper body is the upper trapezius on the right side (52% MMT), with the middle trapezius displaying the second highest reading (37% MMT).On the left side, the highest reading occurred in the subscapularis (33% MMT) followed by the upper serratus (30% MMT). In contrast, the most active muscle in the lower body is the semimembranosus and the long head of the biceps femoris on the right side (28% MMT and 27% MMT). On the left side, the most active muscle is the erector spinae (26% MMT) and the abdominal oblique (24% MMT).
The forward swing starts at the top of swing and ends when the club is horizontal to the ground (early part of down swing). The most active muscle in the upper body during this phase in the upper body on the left side is the rhomboid (68% MMT) and middle trapezuis (51% MMT). On the right side, the most active muscles are the pectoralis major (64% MMT) and upper serratus (58% MMT). The most active muscle during the forward swing phase in the lower body are the upper and lower gluteus maximus (100% MMT and 98% MM) on the right side along with the biceps femoris (78% MMT). On the left side, the most active muscles are the vastus lateralis (88% MMT) and the adductor magnus (63% MMT).