ANALYSIS OF TRUNK MOVEMENT IN PLAYING GOLF

According to many authors in the field of golf medicine, the main causes of back injuries are overuse and poor mechanics of play. Particularly stressful characteristics of the golfswing are reported t d be its rotational character and long-lasting inclination. This hypothesis is generally based on epidemiologic or rather subjective data. In this study however, detailed quantitative descriptions are provided of trunk postures and movements in different types of golfswings. The device used to obtain data is the Portable Posture Registration Set (PPRS), which has been developed at our department. With this method the sagittal inclination of the trunk and sagittal flexion, torsion and lateroflexion of the spine are measured continuously. From the signals of inclination and torsion angular changes, duration times and velocities have been calculated in the different phases of two swinys1(drive and 6 iron). It has been tried to identify specific movement characteristics of the trunk that possibly contribute to the development of back complaints. ,It can be concluded that the inclination of the trunk increases as the swings become smaller. Because of thy deep bending during the positioning of the ball on the tee, this statement does not hold for the drive. The putt in every respect is an exceptional swing with its marked inclination and sagittal flexion, but only marginal torsion and lateroflexion compared to the other swings. The load on the spine is asymmetrical, due to differences in left and right ranges of movement in torsion as well as lateroflexion. In lateroflexion the subjects bent 2-8 times further to the right than to the left. The percentage of the time measured in which the inclinations exceeded 20 degrees varied from 60 to 80%. Comparison with norms used in occupational health reveals that this is a very high percentage and according to these norms, measures for improving the postures involved should be taken as soon as possible, I especially if at least 5% of inclination is accompanied by torsion. Comparison of the calculated forces and force-moments leads to the conclusion that the drive and the putt are potentially the most dangerous swings with respect to the lumbar spine. The contribution of torsion to the spinal load seems to be less important than is generally thought. Inter-individual differences were large and most of them proved t o be highly significant. Due to the fact that only four different subjects have been measured, no conclusions could be drawn regarding the individual swing characteristics that are responsible for back complaints. Yet, some possible indications have been detected on which future research should focus