title: Ball spin in the tennis serve: spin rate and axis of rotation.
abstract: The purpose of this study was to describe three-dimensional ball kinematics including spin axis and spin rate for the flat, slice, and kick serves executed by elite male tennis players. Trajectories of three retro-reflective markers attached to the surface of the ball were measured using a Vicon MX motion analysis system. The local coordinate system of the ball enabled the ball's angular velocity vector to be determined. Mean (+/- SD) spin rates recorded were 127.4 (+/- 56.3), 232.1 (+/- 34.8), and 336.5 (+/- 51.5) rad/s for the flat, slice, and kick serves, respectively. The resultant horizontal velocities of the ball were 52.0 (+/- 2.9), 46.4 (+/- 3.4), and 40.8 (+/- 2.8) m/s, respectively, and a clear tradeoff existed between the development of ball spin rate and horizontal ball velocity. [corrected]. The spin axis and ball velocity vector were close to perpendicular regardless of serve type. Mean angles between the spin axis and the horizontal plane (elevation angles) were 65.68 (+/- 10.28), 68.48 (+/- 6.98), and 54.58 (+/- 8.48) for the flat, slice, and kick serves, respectively. [corrected].
authors.affiliation: School of Health and Sport Sciences, Chukyo University, Toyota, Japan. ssakurai@sass.chukyo-u.ac.jp
authors.forename: Shinji
authors.initials: S
authors.lastname: Sakurai
authors.forename: Machar
authors.initials: M
authors.lastname: Reid
authors.forename: Bruce
authors.initials: B
authors.lastname: Elliott
mesh_terms: D000054:Acceleration; D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D006801:Humans; D008297:Male; D012399:Rotation; D013715:Tennis / Q000502:physiology*; D055815:Young Adult