BETWEEN SESSION RELIABILITY OF THE TURNING POINT CORE TRAINER AS A MEASURE OF SHOULDER HIP SEPARATION ANGLE AND ANGULAR VELOCITY Justin R. Brown 1, Mike Waller 2, Patricia Eisenman 1, Charlie A. Hicks-Little 3 1 Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; 2 Department of Exercise Science and Health, University of Saint Francis, Fort Wayne, Indiana; and 3 Sports Medicine Research Laboratory, Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah. Figure 1. Definition of the shoulder hip separation angle. During the backswing the upper torso rotates backwards. The difference between the upper torso and anterior superior iliac spine is SH SA. METHODS Fifty nine college adults from the University of Utah volunteered for this study (male=33, female 26, age 24.85±4.37 yrs, height 1.72±0.09 m, weight 70.74±12.89 kg, BMI 23.78±2.95 kg/m 2 ). Horizontal arm bars were adjusted to the height just above the shoulders near the level of C-7 and the hip pads were raised to the levels of the anterior superior iliac spine. Prior to entering the Turning Point Core Trainer, participants were allowed to perform a 10 minute self selected warm up. Movement began the neutral position and participants initiated a rotational movement similar to a backswing followed by forward rotation similar to a baseball swing. Participants then completed three 30 second trials. Each trial was separated by a 60 second recovery period. Participants were asked to move thru a comfortable range of motion and exert maximal effort during the forward swing phase. Participants completed each set following the cadence of a metronome in order to control for repetitions (40 bpm). Figure 2. Turning Point Core Trainer. RESULTS Table 1. Means and standard deviations for S AV, H AV, and SH SA for both directions. CONCLUSIONS These data indicate a high level of evidence in support of the reliability of the TP as a tool for assessing rotational variables about the Y-axis, including velocity of both the torso and the pelvis as well as the separation angle between the torso and pelvis. The reliable assessment of such rotational actions support the use of the TP in evaluating the efficacy of conditioning programs on Y-axis rotation of athletes. REFERENCES 1.Alsarraf, B.J. (2011) The validity of the “Turning Point – Core Trainer” in volleyball players. Unpublished doctoral dissertation, University of Utah, Salt Lake City, UT. 2.Myers, J, Lephart, SM, Tsai, YS, Sell, TC, Smoliga, JM, and Jolly, JT. The role of upper torso and pelvis rotation in driving performance during the golf swing. Journal of Sports Sciences 26(2): 181–188, Shahbazi, M. M., Sanders, H. R., & Coleman, S. G. S. (2002). Initial ball speed and force estimation at impact in volleyball and football. 20 International Symposium on Biomechanics in Sports, 318– Szymanski DJ, McIntyre JS, Szymanski JM, Bradford TJ, Schade RL, et al. (2007) Effect of torso rotational strength on angular hip, angular shoulder, and linear bat velocities of high school baseball players. Journal of Strength and Conditioning Research 21(4): 1117– Zhang, Y., & Hsiang, S. M. (2008). A new methodology for three-dimensional dynamic analysis of whole body movements. International Journal of Sports Science and Engineering, 2(2), 87–93. ABSTRACT INTRODUCTION Shoulder Hip Separation Angle (SH SA ) has been determined to be an important factor regarding performance in rotational sports such as golf and baseball. To date three-dimensional motion capture analysis has been used to measure SH SA ; however, due equipment costs and lengthy time periods to analyze measurements it is not practical for sports conditioning coaches. Although three-dimensional motion capture analysis is recognized as the gold standard, a cheaper and quicker tool is needed to evaluate such measurements. The Turning Point Core Trainer (TP) is a device designed to measure SH SA, Shoulder Angular Velocity (S AV ), and Hip Angular Velocity (H AV ); however, data regarding reliability of the TP is lacking. The purpose of this study was to examine between session reliability of the TP as a measure of SH SA, SAV, and H AV. METHODS Fifty nine college adults from the University of Utah volunteered for this study (male = 33, female = 26, age ± 4.37 years, height 1.72 ± 0.09 m, weight ± kg, BMI ± 2.95 kg/m2). This study was approved by the Institutional Review Board at the University of Utah. Each participant completed three 30 second trials on two separate testing days using the TP with zero resistance in the upright position with no forward incline. A one minute rest period separated each trial. Participants were asked to return to the lab 3 to 14 days following the initial testing. SH SA is the difference between the upper torso and hip about the body’s y-axis and was recorded in degrees. In addition, the TP was used to measure S AV and H AV and was recorded in (˚-sˉ ˡ ). All angular velocities were recorded around the y-axis. STATISTICAL ANALYSIS Maximal SH SA, S AV, and H AV for both directions were used for analysis. Intraclass correlations (ICC) were used to examine reliability between testing sessions. In addition, paired t-tests were used to examine differences in SH SA, S AV, and H AV between testing sessions. Statistical significance set at p < All data was analyzed using PASW Statistical software18.0 (IBM Inc., Chicago, IL). RESULTS The results of statistical analysis reveal excellent ICC, and no significant differences between testing days (Table 1). DISCUSSION These results support the hypothesis that the TP has excellent test- retest reliability and support its use for assessing SH SA, S AV, and H AV. ACKNOWLEDGEMENTS We would like to express our gratitude to BioTechnology for use of the Turning Point Core Trainer. INTRODUCTION Sport skills such as the golf swing, baseball pitch, and volleyball spike, are similar in that high velocity must be transferred to the ball for successful skill execution. Sports scientists have identified rotational variables as significant contributors to ball velocity in golf, baseball, and volleyball (1,2,4). Myers et al. (2) investigated the roles of pelvic and upper torso rotation during the golf swing. Their findings indicate that the difference between the sequencing of pelvic and upper torso rotation, also known as the x-factor (Figure 1) or shoulder hip separation angle (SH SA ), is a more important contributor to ball velocity than the magnitudes of the pelvic and upper torso rotational velocities. Understanding the importance of SHSA, hip angular velocity (H AV ) and shoulder angular velocity (S AV ) has been possible due to the use of three- dimensional (3-D) motion capture analysis to examine the kinematic and kinetic aspects of rotational sport skills (3,5). Recent development of the Turning Point Core Trainer (TP) has prompted research regarding its ability to measure the variables used in determining the SH SA. Alsarraf et al. (1) suggested that the TP is capable of quantifying SH SA, S AV and H AV. Furthermore, the TP measurements are available to athletes in real time, eliminating the lengthy time periods for cinematographic analysis. Because the TP is a new measurement tool, its reliability must be established Our purpose was to examine test-retest reliability of the TP as a measure of SH SA, S AV, and H AV. We hypothesized high reliability coefficients would be observed for each variable. Variable Test Day 1 (M±SD) Test Day 2 (M±SD)p valueICC S AVR (˚-sˉ ˡ ) ± ± S AVL (˚-sˉ ˡ ) ± ± H AVR (˚-sˉ ˡ ) 72.78± ± H AVL (˚-sˉ ˡ ) 70.87± ± SH SAR (˚)59.05± ±