Golf is one of the most popular participation sports in the United States, attracting men and women of all ages. According to a National Golf Foundation survey conducted in 2007, there were an estimated 29.5 million golfers aged 6 yr and above, participating at 15,970 different facilities (21). By the year 2020, this number is expected to increase to 55 million participants (12). Golf attracts men and women of all ages, but males have greater representation at 75% (20). By definition, it is a low-impact sport, satisfying the Surgeon General's recommendation for regular, leisure-time activity. In 2007, the American College of Sports Medicine (ACSM) introduced a program known as Exercise is Medicine™. Physicians were urged to recommend physical activity for their patients, as an adjunct to the treatment of hypertension, hyperlipidemia, obesity, and diabetes. Golf is one form of exercise that is effective in risk factor reduction and therefore the prevention of stroke and cardiovascular disease (11).
Although considered low-impact, golf has an alarming rate of injury. The National Electronic Injury Surveillance System (NEISS) of the U.S. Consumer Product Safety Commission reported in 2007 that 52,861 golfers presented to emergency departments with some form of injury (25). On the other hand, a recent German study estimated that 60% of professionals and 40% of amateurs sustain a golf-related injury each year (13). These conflicting data seem to confirm the notion that many athletes never seek medical attention, especially for repetitive motion injury. When compared with a contact sport such as soccer, with injury rates of 4.34 per 1000 in practice and 18.75 per 1000 in games, it would seem that golf is one of the more hazardous sports (1). Also consider that the largest percentage of golfers are those who have the time and resources to devote to their sport. This skews the demographics toward older athletes, who are already at greater risk of injury, and more likely to have preexisting medical and orthopedic conditions (19).
Similar to other sports, the majority of injuries are overuse, while a smaller number are caused by golf cart trauma or occasional ball strikes. In addition to repetitive motion, these injuries always involve some form of training error or biomechanical imbalance. Jack Nicklaus, arguably one of the most recognizable and respected names in the sport, once attributed an amateur golfer's lack of consistency (and perhaps higher rate of injury) to the fact that most don't train at all and simply show up on the course to play (personal communication between Dr. Pearce and Jack Nicklaus, 2005). While a thorough discussion of golf technique is beyond the scope of this article, some insight into the high rate of injury may be gained by reviewing swing biomechanics.
BIOMECHANICS OF GOLF
The golf swing is a complex series of integrated motions, which involve most of the major muscles and joints in the body. It is a closed-chain activity that transfers power from the upper extremity, through core musculature to the feet firmly planted on the ground. The swing can be broken down into four specific phases, including set up, take away, down swing, and follow through (14).
The golf swing is predicated upon developing a stable stance. The feet are placed shoulder-width apart, at the normal angle of gait. Knees should be slightly bent, which will naturally require dorsiflexion of the ankles. The golfer should bend at the waist, but maintain a straight spine, with the neck slightly flexed to allow comfortable sighting of the ball. There are a variety of gripping styles, but in general the trailing hand is lower on the club, necessitating a slight rotation of the shoulders in that direction. Initially, the leading wrist is in a position of ulnar deviation, and the other is relatively neutral. The stability of this stance can be affected by the limited joint range of motion and decreased proprioception, common in older golfers.
The take away emphasizes flexibility and is essential to load the muscular springs, which store power for the down swing. It begins with the upper body coiling on the pelvis toward the trailing hand, placing strain on the lumbar facets, L5-S1 junction, and sacroiliac joints. The intervertebral discs also must withstand increased pressure, as the annulus tightens. The trailing arm is then abducted and externally rotated, while the elbow flexes and wrist radially deviates. The leading arm is internally rotated and adducted across the chest, loading the acromioclavicular (AC) joint and placing the shoulder in a position that promotes impingement. As the elbow naturally flexes, the wrist is held in a roughly neutral position. Transfer of weight toward the trailing leg increases force upon the lateral compartment of the knee and fifth metatarsal, due to supination of the foot. Once again, limited flexibility in any of the associated muscles or joints significantly limits the amount of coiling and therefore the power that can be achieved during the downswing. Similarly, pain from preexisting conditions such as arthritis of the knee or AC joint may limit performance. It is well known that a common cause of injury is altering normal biomechanics to accommodate for some limitation in flexibility, strength, or range of motion (17).
Power is developed during this phase of the swing, and while flexibility is certainly necessary, muscular strength clearly is the most important variable. It begins at the end of take away and continues until club contact with the ball. Although intuitively reversing the above events, there are unique biomechanical forces that must be discussed. The motion is a smooth uncoiling of the spring, beginning with contraction of the leading leg adductor magnus. Momentum is continued as the trailing leg hip extensors and abductors add to rotation of the pelvis. Further acceleration for the upper body is provided by contraction of the transverse abdominal and oblique muscles, while the erector spinae stabilizes the core. Pressure in the intervertebral disc is relieved, but reverse stress is applied to the sacroiliac and facet joints. The leading shoulder is then abducted from the position of impingement by the deltoid muscles, while the trailing shoulder is adducted and internally rotated. During this phase, the leading forearm extensors pull the wrist into slightly dorsiflexion and ulnar deviation, while the trailing arm flexor mass brings that wrist into a more neutral position. At the point of contact with the ball or ground, there is a sudden reversal of these forces, and those muscle groups undergo an eccentric (lengthening) load. The magnitude of force is obviously greater if the club head strikes the ground, rather than the ball itself.
This is the final phase of the swing, and it begins with continued dorsiflexion and ulnar deviation of the leading wrist, while the trailing side undergoes radial deviation and palmar flexion. Suffice it to say that throughout the swing cycle, wrist motion is complex and obviously serves as a possible source of injury. The leading shoulder is abducted to slightly less than 90° and externally rotated, which places it in a position of anterior impingement. The trailing arm is adducted across the chest as the shoulder internally rotates, causing impaction of the AC joint. This is similar to the stress placed upon the leading shoulder in take away, but obviously much more explosive. Abdominal muscles begin eccentric contraction, to slow rotation of the trunk, while the facet and sacroiliac joints absorb the stress. Pressure inside the intervertebral disc once again increases, as the annulus is torqued in the opposite direction. Similar to the AC joint, this is a more violent application of force, which slows momentum of the rotating trunk. Finally weight is transferred to the leading knee, loading the medial compartment and fifth metatarsal, as the ankle inverts and arch supinates. Some golfers raise the trailing heel in follow through, but that doesn't seem to affect their mechanics significantly.
From this discussion, it makes sense that the areas subjected to the greatest stress would be the most likely to suffer from injury, including the leading shoulder, forearm, and back. Looking at the data, this seems to be the case, although women tend to relieve forearm stress at the elbow (51% of injuries to 8%), and in men it is more likely to be the wrist (32% vs. 12%). Also, among amateur men, back pain accounts for 36% of injuries, while in women it is only 12%, possibly due to decreased power and torque during the swing cycle (4) or better flexibility in females. There are some obvious age-related differences as well, since younger players often develop a primary injury, while the seniors tend to aggravate a preexisting condition, such as arthritis (26). As with other sports, the majority of injuries are classified as repetitive motion, or overuse. Golf cart trauma, which in 2007 was responsible for 17,107 injuries, is the noted exception. The highest injury rates were for young males aged 10-19 yr and those over the age of 80 yr. There are no specific statistics regarding how many of these are from use on the golf course (18).
Environmental injuries among golfers include weather and heat illness. There are 30-500 lightning-related deaths a year, and more than 1,000 nonlethal strikes. Thunder can be heard for 12 miles, but lightning can travel horizontally for 40 miles before striking the ground (3,7). This is why golfers are asked to suspend play and leave the course when a storm is in the area. Standing in a field, holding a metal rod overhead may arguably attract lightning, but injury also can occur from walking across a moist fairway wearing metal spikes. Heat injury is another issue for golfers, as their tolerance may be affected by increased age, poor aerobic conditioning, dehydration, alcohol consumption, and use of medications. Symptoms such as muscle cramping, nausea, fatigue, and headache should prompt a golfer to take shade and hydrate (9).
Injuries to the leading shoulder commonly affect both the professional and amateur golfer. The rotator cuff muscles undergo eccentric stress during the uncoiling phase of downswing, leading to possible impingement. The posterior cuff also must deal with repetitive impact loading, decelerating the arm after each swing. Overuse injury results when the relatively weak rotator cuff is fatigued through excessive practice, lack of warm-up, or poor biomechanics and can no longer stabilize the shoulder joint (19). Preexisting AC injury also can be aggravated when the cuff is fatigued. Similarly, the elbow may manifest symptoms of fatigue and instability, particularly the attachment of extensor muscles in the lead arm and flexors of the trailing arm. When struck correctly, the club face slices down on the ball, then continues through to the ground, imparting back spin and creating a divot. This produces an explosive eccentric load on the leading arm lateral epicondyle and trailing arm medial epicondyle, producing tennis elbow and golfer's elbow, respectively. Professional golfers actually have a higher incidence of epicondylitis due to more consistent technique, while in amateurs it usually develops by gripping the club too tightly (19).
The spine is subjected to significant rotational loading and sheer force during the power phase of a golf swing. Although professional golfers can achieve club head speeds of 120 mph, it is the amateur golfer who is more subject to back injury, because poor mechanics in the golf swing lead to 80% more torque and shear load and lateral stress (26). This places significant force upon the intervertebral discs, facet, and sacroiliac joints. Another predisposing factor is the inherently poor core muscle stability most amateur athletes demonstrate. The sacroiliac joint (SIJ) is particularly susceptible to injury, because it serves as a critical link in the kinetic chain, between the power generated above it and the stability provided below. There also is a transfer of weight from one leg to the other at a critical phase of the swing, when the SIJ undergoes maximal rotation. Sacroiliac dysfunction and pelvic instability are said to be responsible for 40% of injuries to the low back, and one would expect the incidence to at least equal that among golfers (8). Another, often overlooked, source of injury associated with golf is carrying the bag of clubs. This subjects the spine to lifting, bending, and twisting, as well as asymmetric loading, since most golfers carry it predominantly on one shoulder (13,26). The newer bags utilizing a back pack type of harness should reduce this form of injury. Finally, the knee is subjected to multidirectional forces during the golf swing, which may aggravate underlying degenerative joint disease or instability. The ankle and foot, as last joints in the closed kinetic chain, can affect the golf swing by not providing a stable set up. Degenerative joint disease, ligament instability, and the natural loss of proprioception that occurs with age can affect the transfer of weight and power during down swing, leading to erratic performance (24).
TRAINING FOR GOLF
While most articles on golf training present some generic discussion of stretching and strengthening, the following program is based upon an understanding of how biomechanics of the golf swing can produce injury. At the most elementary level, training is simply stressing the system, then allowing it to rest, recover, and adapt to a higher level of function. Rest is absolutely essential for adaptation, and it is the one variable most often overlooked in a training program (15). The ancient Greek Olympians were the first to recognize the benefits of periodization. They divided training into macrocycles, or seasons of the year, then further into microcycles, representing hard and easy days or weeks. The preseason focuses on strength training and conditioning, beginning after a period of rest, the length of which is sport-specific. During the competitive season, strength training gives way to stretching, and injury prevention. After competition is finished, the post- or off-season allows for rest and recovery (10). Periodization is important in golf training as well, and fortunately rest is dictated by climate in much of the United States. In those areas where golf can be enjoyed year-round, a forced period of 4 to 6 wk off should be included in the training plan. The variables to be addressed in any program include flexibility, muscular strength, and endurance. The latter is important for golf, if a player intends to walk the course for aerobic exercise. While poor technique is clearly a major predisposing factor for injury in any sport, specific training in swing mechanics is beyond the scope of this article and covered in numerous resources elsewhere (12,14). A few points concerning the warm-up deserve mention, however. After completing the stretching routine, a golfer should take some practice swings, beginning with the short irons (7,8,9). Progressing through the middle-distance irons, to the fairways woods (3,5), then the driver helps to slowly increase torque applied to the spine and pelvis. Most golfers finish their warm-up by putting, which is less stressful, but involves prolonged bending at the waist.
A stretching program is usually initiated in the preseason, then incorporated into a pre-game warm-up. Although somewhat controversial whether it helps prevent injury (16,23) or not (13), from the previous discussion, flexibility obviously is necessary for a proper take away and follow through. Golf-specific stretching exercises should address those areas that are necessary for proper mechanics and subsequently the most injured, such as the shoulders, forearm, and back. The following program should be completed daily for the first 6 wk of training, then before each round. Concentrate on relaxing the region being stretched, hold each position for 30 to 60 s without bouncing, and transition smoothly from one exercise to the next.
Begin by standing with feet shoulder-width apart, arms comfortably at the sides, palms in. With elbows straight, slowly raise the arms to the side until they meet overhead, then slightly cross so the palms are touching. Intertwine the fingers, and complete the stretch by reaching as high as possible overhead, upper arms pressing against the ears. From this position, release the hands then bend one elbow and place the palm flat against the upper back. With the other arm, grasp the elbow and pull it toward the midline, then repeat for the other side. Next, reach straight out in front with one arm, elbow locked, and palm down. Grasp the hand and forcefully flex the wrist, to stretch the forearm extensors. Next rotate so the palm is up, and extend the wrist to address the forearm flexors, then repeat both exercises for the opposite side. Now grasp a golf club with one hand on the grip, and other near the head. With elbows straight, raise the club completely overhead, and extend the spine, reaching as far back as possible. Hold for 30 s, then bring the club forward, and bend at the waist, coming as close to the ground as possible. Assume the starting position, and bend laterally to each side. Return the club overhead again, and twist as far as possible to each side, holding for 30 s. If you are particularly inflexible or prone to low back pain, this stretch should be repeated two or three times. For completeness, some may wish to include stretches for the lower extremity, but these authors feel that would add little to the program, since the reported rate of injury is quite low (2).
The basic principles of strength training apply to golf, as any other sport. In general, weight work is done every other day during the 6 to 8 wk preseason, then decreased to once a day or even eliminated when competition begins. Opposing muscle groups are exercised in alternating pairs, with 12 to 15 repetitions in sets of two to three, emphasizing perfect form. The main muscle groups to be addressed reflect those that are most frequently injured, including the shoulders, forearm, and trunk or core (19). The rotator cuff muscles stabilize the shoulder so prime movers (deltoid, pectoralis) can move the arm. These muscles only have mechanical advantage when the elbow is held at the side, and they act as internal or external rotators. Using a pulley system or elastic band, begin with the elbow at the side, bent to 90°, and arm fully externally rotated. Grasp the band, then perform a slow internal rotation. When complete, relax and slowly allow the tension to return your arm to the starting position. Repeat this motion 25 times, and alternate with two to three sets of internal rotation against resistance, before repeating on the other side. Forearm strengthening alternates between the flexors and extensors. With your arm in the same starting position as above, starting with a 2-3 lb. weight (goal of 10 lbs), grasp a 10-lb weight with the palm down. Dorsiflex the wrist, pause, and then slowly allow the weight to palmar flex the wrist. Lengthening a muscle to do work is known as eccentric contraction, and in this case helps to protect the wrist from sudden deceleration of club impact with the ground. This helps reduce the incidence of lateral epicondylitis (tennis elbow), which accounts for 51% of injuries in female golfers. Next, turn the palm up to strengthen the forearm flexors, and perform two to three sets of each before addressing the other arm. A program of core stability for golf should place emphasis on the transverse and oblique abdominals, which undergo the most stress in providing torque for the golf swing. Many good resources can be found that discuss the subject of core stability in much greater detail than possible here (5).
Mark Twain once said, "Golf is a good walk spoiled." The average golfer covers approximately 3 miles while playing 18 holes, and that certainly meets the Surgeon General's recommendation for aerobic exercise. An excellent training program for walkers can be found at the Rockport Walking Institute's Web site (22). They describe a 1-mile walking fitness assessment, which then designs a 20-wk program, based upon the needs of that individual. Aerobic endurance in the form of walking or cycling also has been shown to reduce the recurrence of low back pain after injury and should be included in any treatment program (6).
Golf is a low-impact, aerobic sport, which can be enjoyed from childhood through the retirement years. It satisfies the Surgeon General's recommendation of low-intensity exercise for physical fitness but carries a high annual injury rate of roughly 40%. It is the opinion of these authors that a major factor in the development of injury is a lack of sport-specific training and inadequate preparation prior to golfing. This program was designed to help reduce stress in the golf swing, taking into consideration the biomechanics of this complex motion. By following appropriate off-season conditioning and pre-game warm-up, it is believed that the incidence of golf injuries could be reduced significantly.