B. J. Alsarraf, J. R. Brown, M. . Waller, P. . Eisenman, and C. A. Hicks-Little, “Reliability of the Turning Point Core Trainer as a Measure of Shoulder Hip Separation Angle, Shoulder Angular Velocity, and Hip Angular Velocity During Volleyball Spiking Actions”, 90, vol. 2, no. 1, pp. 1–9, Jan. 2015.