Separation of the shoulders and hips is an important contributor for rotational sports such as baseball and golf. Most recent has utilized Motion Capture technology. A new instrument has been developed as a tool to measure separation angle and can also be used to train the core musculature. The primary aim of the current study was to examine the reliability of shoulder hip separation angle (SHSA), shoulder angular velocity (SAV), and hip angular velocity (HAV) as measured using the Turning Point Core Trainer (TP) during volleyball spiking actions. Voluntary participants included 14 collegiate, Division I, female volleyball players from the University of Utah, ranging from 18-30 years of age. Participants completed 10 volleyball spike actions will fastened to the TP. SHSA was calculated at the height of the back swing. Participants were asked to provide maximal velocity during the forward phase thus providing SAV and HAV. Analysis for reliability demonstrated high Cronbach’s alpha coefficients across the 10 SHSA, SAV, and HAV (a =.98; a =.91; a =.94), respectively, indicating excellent internal consistency reliability for the TP. Follow-up research should examine whether or not training female outside hitters to increase SHSA at the top of the back swing, will increase SBV during either DL or DAC spikes. The TP measure of-axial rotation during spiking the internal consistency of the measures was high.
This study contributes to the existing literature regarding test re-test reliability using the Turning Point Core Trainer to assess torso rotation and the impact it has on sports performance.
Aragon-Vargas, L.F., 2000. Evaluation of four vertical jump tests: Methodology, reliability, validity, and accuracy. Meas Phys Educ Exerc Sci., 4(4): 215–228.
Barker, S., R. Craik, W. Freedman, N. Herrmann and H. Hillstrom, 2006. Accuracy, reliability, and validity of a spatiotemporal gait analysis system. Med Eng Phys., 28(5): 460-467.
Brown, J.R., B.J. Alsarraf, M.M. Waller, P. Eisenman and C.A. Hicks-Little, 2014. Rotational angles and velocities during down the line and diagonal across court volleyball spikes. IJKSS, 2(2): 1-8.
Bruton, A., J.H. Conway and S.T. Holgate, 2000. Reliability: What is it and how is it measured? Physiotherapy, 86(2): 94–99.
Cohen, D.B., M.A. Mont, K.R. Campbell, B.N. Vogelstein and J.W. Loewy, 1994. Upper extremity physical factors affecting tennis serve velocity. The Am J Sports Med, 22(6): 746–750.
Dempster, P. and S. Aitkens, 1995. A new air displacement method for the determination of human body composition. Med Sci Sports Exerc, 27(12): 1692-1697.
DeVellis, R.F., 1991. Scale development. Newbury Park, NJ: Sage Publications.
Fields, D.A., M.I. Goran and M.A. McCrory, 2002. Body-composition assessment via air-displacement plethysmography in adults and children: A review. Am J Clin Nutr, 75(2): 453-467.
Kaplan, R.M. and D.D.P. Saccuzzo, 2008. Psychological testing principles, applications, and issues. 7th Edn., Belmont, CA: Wadsworth Cengage Learning.
Karduna, A.R., P.W. McClure, L.A. Michener and B. Sennett, 2001. Dynamic measurements of three-dimensional scapular kinematics: A validation study. J Biomech Eng., 123(2): 184–190.
Myers, J., S.M. Lephart, Y.S. Tsai, T.C. Sell, J.M. Smoliga and J.T. Jolly, 2008. The role of upper torso and pelvis rotation in driving performance during the golf swing. J Sports Sci., 26(2): 181–188.
Shahbazi-Moghaddam, M., R.H. Sanders and S.G.S. Coleman, 2002. Initial ball speed and force estimation at impact in volleyball and football. Accepted for presentation and publication. In K. Gianikellis (Ed.), Scientific Proceedings of XXth International Symposium on Biomechanics in Sports. pp: 318-321.
Stodden, G.S.D.F., S.P. Fleisig, S.L. McLean, L.J. R. and Andrews, 2001. Relationship of pelvis and upper torso kinematics to pitched baseball velocity. J Appl Biomech, 17(2): 164–172.
Zhang, S.M.Y. and Hsiang, 2008. A new methodology for three-dimensional dynamic analysis of whole body movements. Inter J Sports Sci Eng., 2(2): 87–93.