The Analysis of Knee Joint Movement During Golf Swing in Professional and Amateur Golfers (P1)
Golf is the one of the most popular sport in the world. It has been estimated that more than 55 million people around the world participate in this sport and there is the tendency to increase. As numbers of people participating in golf are growing, incidence of golf injuries are increased. Besides low back, the knee is another region that frequently injured. This may be due to modification technique in back swing and follow-through. Incorrect golf swing technique may create more compressive force on the knee joint during both feet were fixed on the ground. Moreover, knee joint structure is not proper for rotation but these movements are essential for golf skill. The chance of knee injury is high risk because this joint has to take body weight and move all the time, this problem is very importance. Research studies have revealed information about golf and knee injuries. According to McCaroll large Q angle and pronation of the feet increase the stress on the patellofemoral joint during the golf swing when valgus forces applied to the knee. A case of osteochondal fracture of the patella has been reported in a golf player. During the follow-though phase, the patella dislocated in the right knee due to internal rotation of tibia.
Biomechanics of golf swing has been widely investigated in order to improve performance and prevent injury. A recent review by Farrally et al. Summarized research finding in golf and identified the application of sound biomechanics to improve golf performance as important. By using qualitative and quantitative analyses tool, to describe the movement pattern of the golfer’s swing as well as the resultant of joint torque. In addition Egret showed in his study about kinematic of the golf swing that men flexed their left knee more than women during the backswing. Nevertheless, these two kinematic patterns showed no significant differences in the club head speed.
According to the knee injury in golf swing, it is likely that the understanding of knee movement during swing can prevent and decrease injury. Such knowledge is importance for golf swing improving. In addition, there very few researches about mechanic of knee joint during golf swing, no comparison 3-D kinematics differences of the knee motion between professional and amateur golfers. Therefore, the purpose of this study to investigate and compare threedimensional kinematics differences of the knee motion between amateur and professional golfers.
Fifteen male professional golfers (mean age 21.87 ± 1.9 yrs; ht. 173.1 ± 5.0 cm; wt. 68.1 ± 10.2 kg) and fifteen amateur golfers (mean age 18.0 ± 1.7 yrs; ht. 172.7 ±5.3 cm; wt. 65.6 ± 9.2 kg; handicap 4.5 ± 2.9) free form hip, knee or ankle injury in the past six months will be recruited for the study. All subjects were right-handed players, and subsequently utilized their left leg as lead leg during the golf swing. They are voluntarily to participate in this experiment. The subjects will be selected by purposive sampling.
Three-dimensional kinematic data will be collected with four high-speed digital video cameras (Basler A504kc from German). Golf swing motion will be captured at the sampling rate of 500 Hz and recorded on a hard drive. Tools are calibrated according to manufacturer recommendations. First, set the area for skill showing, rectangle is set after that, measure the distance of assume axis x, y, z (wide x long x high) that equal 1.595m. x 1.595m. x 1.350m. and use poles or calibration wand for assign value in z axis (Fig. 1). The twelve control points will be used to determine the calibrated volume space via DLT method. The camera calibration wand will be captured for 3 sec and will be digitized later.
Fifteen retroreflective markers will be attached on right and left lower extremities on the following locations (Fig. 2). Two retroreflective markers will be attached on golf club head and stick. The positions of markers attached on right and left lower extremities are adopted from Helen Hays marker set which has been widely used in gait analysis.
Subjects will be suggest to warm-up (static and dynamic stretching) about 5-10 min. in order to prepare body readiness prior to the test. When subjects be ready, starting signal will be sent. In order that subjects must swing time by time for 3 times. Each of swing subjects receive 2-3 min. to rest during data saving.
Data Treatment and Analysis
Following data collection, all markers will be digitized using the SIMI Movement Analysis software version 7.5.297. Direct Linear Transformation (DLT-11) method is used to reconstruct three-dimensional raw coordinate data. Raw kinematic data will be filtered with a Butterworth filter with optimal cut-off frequencies determined by residual analysis. Segmental coordinate systems of shank and thigh will be established from three non-collinear markers on each segment (fig. 3). Knee joint kinematics then will be determined based on method of Vaughn et al.
The statistical package SPSS for Windows (SPSS, Chicago, IL) will be used for all statistical procedure. A Sharpiro-Wilk test will be used to ensure the normal distribution of the data. If the data is normally distributed, independent t-test will be used to determine the differences of three-dimensional knee joint kinematic variables as well as club head velocities between professional and amateur golfers. If the data are not normally distributed, Mann-Whitney U test will be used to determine the differences. Differences will be considered at the p<0.05 level