Oqus 300 system

A 19-camera, 1000 Hz Oqus 300 system and Qualisys Track Manager (Qualisys AB, Gothenburg, Sweden) were used to collect and calculate the three-dimensional coordinate data. Thirteen dynamic and a further nine static spherical retro-reflective markers of sizes varying from 6.4 mm to 12.7 mm were used for tracking the left arm and club. A further 3 pieces of retro-reflective tape were used for the club and ball tracking. The details of the marker locations and attachments can be found in Appendix A.

A 12-camera, 1000 Hz Oqus 300 system and Qualisys Track Manager (Qualisys AB, Gothenburg, Sweden) were used to collect and calculate three-dimensional coordinate data.
Three spherical retro-reflective markers each with a diameter of 12.7 mm were attached to the crown of the club, and two pieces of retro-reflective tape were attached to the shaft just below the grip and a further 20 cm below that for dynamic tracking. Five 6.4 mm diameter markers were attached to the clubface (figure 1), and removed after static capture. The ball position was defined by a small piece of unobtrusive retro-reflective tape attached to the top of the golf ball. During processing this point was translated vertically downwards by the radius of the ball and thus represented the centre of the golf ball. A similar marker set has been used previously and validated by Betzler et al. (2012) . Each golfer used their own driver with which they were familiar. Whilst the clubhead markers added 10g to the mass of the club, this mass adjustment has not been shown to be reliably detected by golfers and has little effect on shot performance (Harper, Roberts, & Jones, 2005) . No negative consequences of marker attachment were reported by the players in the present study.