June 2016

Golf swing biomechanics: Footwear considerations

Orthotic-Devices-for-the-WinBy Patricia Pande, MClScPT, CSCS, CPed

Sponsored by an educational grant from Medi USA.

With the rise of a new crop of young stars and the anticipation of its Olympic debut this year, golf continues to be immensely popular for players and spectators alike. Golfing is a highly coordinated sport that, by its nature, is associated with risk of repetitive motion injuries.1 Its broad appeal, however, makes it a cross-generational activity, attracting players with varying levels of ability and talent.

Golf-related injuries of the spine and upper extremities have been documented in the literature,2 but there is a lack of information about its impact on the foot and ankle. Blistering is the most commonly reported lower extremity injury, but there are reported cases of plantar fasciitis and ankle sprain in the clinic.3 Further, until quite recently, little attention had been paid to the role of the foot and ankle in golf’s biomechanics, particularly during the swing.4,5 An understanding of these mechanics will enhance clinicians’ ability to help improve performance and prevent injury in golfers, particularly with the use of foot orthoses.

Understanding the golf swing

In a survey of golfers, 46.2% reported sustaining an injury during the golf swing.2 The swing accounts for nearly 60% of the golfer’s game,6 and puts significant stress on the lower body.

To better understand the demands on the body, this analysis will discuss the swing motion in terms of four phases: ball set up and foot stance, backswing, downswing (acceleration and ball impact), and follow through (early and late).

Foot stance. To align the body with the target—the golf ball—the golfer’s weight must be fairly equally distributed between the feet, with slightly more weight on the back foot.7 In the optimal golf swing, the golfer rotates around a fixed back foot, then transfers the force to the front foot. Initial foot placement is critical, as a firmly planted foot improves shot accuracy and distance; conversely, foot slippage may negatively impact performance.8

Backswing. Golf involves large amplitude movements of the lead hip—away from the ball on the backswing and toward the left on the downswing in a right-handed player (opposite for a left-handed player).9 The backswing positions the club head for a powerful downward motion toward the ball.10 During the backswing, the lead leg undergoes external rotation secondary to the right pelvic internal rotation. This results in 60% to 80% weight transfer to the trailing side10 and concomitant flexion, adduction, and hip internal rotation on the same side.11 The trunk rotation required to increase the club head speed puts stress on the lumbar spine and may harm overall spine health.9

If the range of motion on the lead side hip is restricted, the spine may be negatively affected. However, allowing the lead heel to rise from the ground during the backswing may allow more pelvic rotation and decrease stress on the spine.9

Downswing. The goal of the downswing is to return the club head to the ball with maximum velocity and accuracy.10 In the modern golf swing, the lead hip initiates and accelerates the left backward pelvic motion (in a right-handed golfer) by activating the left vastus lateralis and adductor magnus, which are active through weight transfer, and the right gluteus medius, which drives the rotation.11 Similar to the backswing, reducing the fixation of the foot during rotation toward the ball may also decrease the compressive, rotational, and side-bending forces experienced by the spine.9

Because club head velocity is associated with weight transfer to the lateral target forefoot in amateur golfers, footwear or orthoses that shift weight anteriorly and laterally could help increase club head speed in this group.12 Specifically, elevating the heel and providing medial arch support may increase club head speed in golfers at this skill level.

The downswing is associated with high peak loads on both the lead and trail knee.13 In a study of healthy collegiate golfers,14 the magnitude of the knee varus/adduction moment on the target side (just after ball contact) is higher than values reported in the literature for gait and stair ascent. These findings may be relevant for golfers with medial tibiofemoral compartment arthritis and must be considered in return to golf after knee surgery.14

Changing the initial foot position from straight to externally rotated has not been shown to reduce valgus stress at ball impact14 but may be effective in reducing the varus force. Interestingly, footwear design (spiked vs spikeless) does not affect these forces.8,13 Lateral wedging of orthoses may significantly reduce varus force at the knee in the golfer with degeneration of the medial compartment.15 However, a comprehensive full-body approach may be a more effective way to minimize the stresses associated with hip, knee, and foot rotation. According to Wadsworth, treatment must always “address assessment of deficiencies in the kinetic chain.”16

Follow through. The purpose of follow through is to decelerate the body and club head.10 As the trunk rotates to the left and hips externally rotate, the lead ankle simultaneously internally rotates and supinates.10 Fradkin et al found that most foot and ankle injuries in golfers were related to inversion (supination) of the ankle during follow through.2 The rotational motions may also result in increased stress to the ligaments and meniscus of the knee.17

Footwear and injury reduction

Golf shoes with traction are almost as old as the sport; they first appeared in 1857.18 During the 1900s, golf shoes were basic wing-tip Oxfords with spikes. Because spikes damaged the golf course turf, however, design changes followed. Footwear is now specialized for golf biomechanics, but sole shape and spike configuration is much the same as in the past.8 Williams and Cavanagh identified shear and vertical force as the most important elements influencing golf shoes’ resistance to slippage, force generation, and stability.19 Counterintuitively, modern golf shoes have not proven to impact drive accuracy or distance.8 However, flexible custom orthoses have been associated with increased club head velocity, as discussed below.5

There has been little study of how golf shoe design parameters and comfort influence injury prevention. Shoes do need to provide stability, support, and traction while allowing divergent use of both feet and minimizing the discomfort and fatigue associated with negotiating a golf course’s variable topography. It is a formidable challenge for a single shoe design to meet the complex biomechanical demands of the golf swing while providing enough comfort to traverse uneven ground. Addressing the variety of demands on the foot by switching footwear at differing times in the game could be a strategy in recreational golfers with disabling foot and ankle pain.

Foot orthoses

6Medi-shutterstock_220555234-copyThe biomechanics of golf demand foot orthoses that can address a multitude of foot positions. Although prefabricated orthoses can help improve posture in the back foot, the effect may be limited by the devices’ inability to fully address the differences between the lead and trail feet.20 Semicustomizable carbon fiber orthoses that can accommodate posts or pods as needed merit individual study in the clinic or on the golf course. The asymmetrical mechanics of the golf swing are similar to the cutting motions in other cleated sports. Therefore, transferring stress with carbon fiber while maintaining flexibility may positively affect the forefoot during the golf swing, as it has been shown to do during cutting.21

Flexible customized foot orthoses have been associated with a positive influence on pain and fatigue in golfers.4,5 The researchers noted the results cannot necessarily be extrapolated to all golfers, as the study participants were drawn from a specific population and the orthoses were of a specific design. Nonetheless, the positive findings are worth considering in the clinical management of any golfer.

Dynamic postural control is a key component of the backswing and follow through.22 A recent study suggests that flexible orthoses may positively influence golfers’ balance and proprioception,4 which suggests such devices may have benefits for those aspects of the golf swing. This study had several limitations—it lacked a control group, the potential effect of the learning curve was not assessed, and the sample size was too small for full extrapolation—however, the findings suggest the need for further research.4

Ensuring comfort without disrupting balance will continue to be of paramount importance for a long and healthy golf habit, in spite of the variable research findings.  As such, orthotic management in golf should consider:

1. Flexibility to allow the foot’s dynamic function, including pronation/ supination, mediolateral movement, heel lift, and foot rotation;9,10

2. Appropriate fit within the shoe to reduce slippage during downswing and ball impact;8

3. Full-length insert to reduce the translation of the foot within the shoe and potentially enhance accuracy and speed;8

4. Inserts with a textured topcover to improve the coefficient of friction at the foot–orthosis interface and potentially enhance proprioceptive input and balance;8,22,23

5. Modifiable or semimodifiable devices to address the variable demands on the foot during the golf swing and while ambulating on the course;10

6. Modifiable to allow wedging laterally to reduce varus force at the knee in golfers with medial knee pathology;15

7. Inserts composed of lightweight carbon fiber to allow redistribution of force in the forefoot;21 and

8. Lightweight and flexible materials to reduce fatigue associated with long periods of repetitive weightbearing and load shifting.23

The effects of orthoses on foot and ankle mechanics, as well as knee valgus and hip torque in golfers—among other sports—merit  further study. The growing number of mature golfers who wish to pursue the sport in spite of “failing joints” must be met by advancements in orthotic science. Addressing deficiencies in the kinetic chain will have an impact on both injury prevention and performance enhancement and forge the way to a better, healthier game.

Patricia Pande, MClScPT, CSCS, CPed, is a physical therapist, pedorthist, and strength and conditioning specialist based in Durham, NC. She is the founder of FootCentric, an online continuing education company dedicated to comprehensive, multidisciplinary foot treatment.

REFERENCES
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  7. Jones RK, Chapman GJ, Parkes MJ, et al. The effect of different types of insoles or shoe modifications on medial loading of the knee in persons with medial knee osteoarthritis. A randomised trial. J Orthop Res 2015;33(11):1646-1654.
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  15. Aboutorabi A, Bahramizadeh M, Arazpour M, et al. A systematic review of the effect of foot orthoses and shoe characteristics on balance in healthy older subjects. Prosthet Orthot Int 2016;40(2):170-181.
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One Response to Golf swing biomechanics: Footwear considerations

  1. teri Green says:

    I have found that wearing a heat mold orthotic under the golf shoe’s insole will give greater control on the golfer’s swing. Controlling pronation on the swing will give greater strength to the driver.
    Teri Green
    Atlas Biomechanics

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