Diagnosing and Measuring the Yips in Golf Putting: A Kinematic Description of the Involuntary Movement Component That Is the Yips

The yips is an involuntary movement disrupting the smooth motion of the golf putting stroke. The study's aim was to provide an objective measurement of the yips by identifying and quantifying the kinematic parameters of the involuntary movement component. Additionally, muscle activity of the forearm was compared between yips-affected and unaffected putts. The study uses a within-subject design, which allows the comparison of yips-affected putts with unaffected putts within the same participant. Six yips-affected and 6 unaffected experienced golfers performed 90 putts each alternating between both hands, the right hand only, and the left hand only. The putts were performed on an artificial indoor green and alternated between putts with ball and putts without ball. The putting motion was captured using a 12-camera VICON system. Additionally, muscle activity of forearm flexor and extensor groups was measured on both arms. It was found that the yips were provoked 100% reliably when putting the ball with the dominant hand only. The yips largely disappeared when there was no ball. Moreover, kinematic analyses show that a higher maximal rotation velocity and a larger number of directional changes in the affected wrist's rotation clearly distinguished the yips-affected from unaffected putts. The EMG results revealed no significant differences between yips-affected and unaffected putts. Overall the results show that putting the ball with the dominant hand only reliably provokes the yips that can be measured by the wrist's rate of rotation and the number of the rotation's directional changes.