| 摘要: | The purposes of this study were to investigate the segments orientation and foot pressure variables during golf swing of professional and amateur golfers and create a new set of orthogonal variables that describe the majority of variance in the original dataset using principle component analysis (PCA) during the golf swing. Twenty professional and Twenty amateur right-handed golfers from Taiwan were participated. Participants were divided into professional and amateur group based on handicap. Fifteen successful swings of 7-iron and driver, respectively, were performed in an indoor screen golf system room. Kinematics and kinetics data were collected using inertial measurement unit (IMU) sensors and wireless pressure insole system. Golf swing was divided into 10 events (① takeaway (TA), ② mid-backswing (MB), ③ late-backswing (LB), ④ top of backswing (TB), ⑤ early-downswing (ED), ⑥ mid-downswing (MD), ⑦ ball impact (BI), ⑧ mid-follow-through (MF), ⑨ late-follow-through (LF), ⑩ finish (FIN)). The resultant of orientation vector of 24 segments were calculated. Foot area was divided into 4 areas (fore-medial (FM), fore-lateral (FL), rear-medial (RM), rear-lateral (RL)). Peak pressure of each area was calculated at 10 events. PCA was using as statistical method to identify new sets of orthogonal variables that describe the majority of variance during the golf swing. Golfer’s every shot except the error data was set as individual data. 24 whole body segments were divided into the upper body (15 segments) and lower body (9 segments). 3 events (i.e. MD, BI, MF) in functional swing plane (FSP) was selected for PCA.
Based on the result, the new set of orthogonal variables was as follows: ① Whole upper body segments orientation at BI, and right lower leg, right foot, right toe, left upper leg, and left lower leg orientation in FSP were the new sets of orthogonal variables for SUM’s 7iron. ② Whole upper body except golf club segments orientation at MF, and right lower leg, right foot, and right toe in FSP were the new sets of orthogonal variables for professional’s 7iron. ③ Whole upper body except left forearm, left hand, and golf club orientation at MF, and right lower leg, right foot, right toe, left upper leg, and left lower leg orientation in FSP were the new sets of orthogonal variables for amateur’s 7iron. ④ Whole upper body except golf club orientation at MF, and right lower leg, right foot, right toe, left upper leg, and left lower leg orientation in FSP were the new sets of orthogonal variables for SUM’s driver. ⑤ Whole upper body except golf club orientation at MF, and right lower leg, right foot, and right toe orientation in FSP were the new sets of orthogonal variables for professional’s driver. ⑥ Whole upper body orientation at MF, and right lower leg, right foot, right toe, left upper leg, and left lower leg orientation in FSP were the new sets of orthogonal variables for amateur’s driver. To sum up, based on the results, the present study could give suggestions to amateur golfers as follows: ① In terms of 7-iron, amateur golfers should pay attention to upper body orientation at MD and pelvis orientation in FSP ② Amateur golfers should concentrate COM on right toe at BI and don’t move COM too much to the left side (i.e. target side for right-handed golfer) artificially during 7-iron shot. ③ In terms of driver, amateur golfers should pay attention to upper body orientation at BI, and pelvis and left leg orientation at MF. ④ Amateur golfers should keep COM on the right toe after BI during driver shot. Moreover, PCA was demonstrated to be a useful tool to determine critical factors of golf swing. It might be used for offering useful segments orientation and foot pressure information to amateurs for improving performance. |
