PURPOSE: The biomechanics of the golf swing have been studied extensively but specific metrics related to golfing proficiency have not been identified. The purpose of this study was to compare golf swing biomechanics between proficient and average golfers and thereby identify specific metrics associated with golfing proficiency.
METHODS: Twenty-two male golfers were categorized as proficient (golf index <6, n=10) or average (golf index 10-24, n=12). Three-dimensional kinematics and ground reaction forces (GRF) were recorded as subjects hit standard golf balls into a net using a driver. Angular velocities of the pelvis, trunk, lead arm and golf club, as well as X-factor, were calculated from the kinematic data. GRF under the lead and back legs are expressed as a % of bodyweight. The effect of golf proficiency on golf swing biomechanics was assessed using independent samples t-tests.
RESULTS: Proficient golfers were younger (26±6 yr vs. 48±16 yr, P=0.001) but did not differ in height (P=0.114) or weight (P=0.330). Peak pelvis and trunk velocities were higher (P=0.004) in proficient golfers (525.1±91.6 deg/s and 621.8±89.4 deg/s, respectively) versus average golfers (414.3±67.7 deg/s and 521.3±75.5 deg/s, respectively) but peak club velocity was not different (2509.8±226.1 deg/s vs. 2446.6±420.3 deg/s; P=0.675). Proficient golfers had greater X-factor at the top of the backswing (56.0±6.0 degrees vs. 44.1±11.4 degrees, P=0.008), greater peak X-factor (61.4±5.7 degrees vs. 49.3±11.8 degrees, P=0.008) and greater X-factor at ball impact (34.2±5.8 degrees vs. 22.5±6.5 degrees, P=0.001). Proficient golfers had a higher peak GRF on the lead leg compared with average golfers (142±17 %BW vs. 122±18 %BW, P=0.018), while paradoxically having a lower lead leg GRF at ball impact (56±18 %BW vs. 89±17 %BW, P<0.001).
CONCLUSIONS: The higher X-factor in proficient golfers is indicative of a more effective use of elastic energy in the trunk that is sustained through ball impact. The GRF data indicate that proficient golfers more effectively loaded the lead leg during the initiation of the downswing and more effectively unloaded the lead leg prior to ball impact. In conclusion, golf swing proficiency appears to be a function of a more effective transfer of power from the ground and a more effective use of elastic energy in the trunk.