Spin Rates

Spin rate were collected on a hard court with a player hitting cross court forehands from the baseline from a ball machine positioned on the opposite end baseline. The Lobster Phenom Electric Ball Ball Machine launched a new Tretorn Serie pressurised tennis ball at 90 mk/hr. Pre impact the ball was travelling on average 18.4 km/hr (SD 3.5 km/hr) and an average spin rate of 2936 rpm (SD 86 rpm).

The test was conducted using an Olympus i-Speed FS at 1000 fps (50 mm lens). Camera was placed at right angles to the player to capture the incoming ball speed, spin and trajectory in addition to contact, outgoing ball speed, trajectory and spin rate. Six Balls were launched from ball machine with filming of balls 2-6 (4 balls) each time. All shots had to land in the cross court corner at the other end over the service line otherwise the trial was re-filmed. Balls were marked with six 'x' on the 'X-Y-Z' axis for analysis.

The player use eight new Volkl Organics 10 racquets (295 gram frames). (Rod to insert Swing Weight, Balanced Point, Mass, Torsional etc) All rkts were match using Flex Infinity Racquet Analysis Machine. Grip size 3, with tournagrip.

Strings: Flex Infinity Range 1.15, 1.20. 1.25, 1.30 mm in Grey and White were tested in addition to Flex Hybrid (Main: 1.25 mm / Cross: 1.20 mm White (pre-stretched), Luxilon ALU Power 1.25 mm, Babolat Blast 1.25 and Gut Hybrid (Main: VS Touch 1.30 / Cross: Flex 1.20 mm white pre-stretched.

Stringing Machines: The 8 Flex Infinity strings were strung on a Technifibre SP70 at Main 54 lbs / Cross 52 lbs. two days before the test. The additional strings were strung on the day using Wilson Baiardo

Analysis was done using i-Speed Video Suite (Ver 3.0.2.6)

Acknowledgements:

Brendan Slaven - Olympus - Use of Camera and technical support, design and analysis of data

Peter McCraw - International Tennis Specialist

Adam Kennedy - Player

Mat O'Brien - High Performance Tennis Coach, MRT - Use of stringing machine and assistance on the day

Quantum Leisure - Balls / Ball Machine

Volkl Europe - Rkts Shaun Frost?

Notting Hill Pinewood Tennis Club - Duncan Sillato (Head Coach) Use of Facilities for testing

Other support - Ben Kasehagen - Deakin University Student. Daniel Laoang - Tennis Coach