Optimizing Freestyle Flip-Turn Technique
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UNIVERSITY OF HAWAII LIBRARY OPTIMIZING FREESTYLE FLIP-TURN TECHNIQUE A"THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI'! IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN KINESIOLOGY AND LEISURE SCIENCE DECEMBER 2005 t,' i··" By AmyE. Patz Thesis Committee: Jan Prins Coop De Renne Paul Kingery • We certify that we have read this thesis and that, in our opinion, it is satisfactory in scope and quality as a thesis for the degree of Master of Science in Kinesiology. , , ~. • THESIS COMMITTEE " . Chairperson """," Gi:d*l'~~ ii J Table of Contents Acknowledgements .................................................................. iv Abstract ................................................................................. v List of Tables and Figures ............................................................ vi Chapter 1: Introduction ............................................................... 1 Statement of the Problem .... .'; ............................................. 5 Need for the Study ........................................................... 5 Operational Definitions ..................................................... , 5 Independent V ariab Ies .............................................. 5 Dependent Variables ................................................ 6 Delimitations ...................................... ~ ................... : ....... 6 Limitations .................................................................... 7 Chapter 2: Review of Literature .................................................... 8 Literature Review Overview ....................................... .' ........ 8 Importance of Turns ................................................... : ..... , 8 Turning Time ........................ c....................... , ................ 11 Push-off velocity as the Criterion Value ................... ~ .............. 12 Overview of the Phases of a Flip-Tum .................................... 14 The Approach ................................................................ 14 TbeTurn ...................................................................... 16 Push-Off ...................................................................... 16 Tuck Index .......................................................... 17 Foot Plant Position ........... : ..................................... 18 WaH Contact Time ................................................. 19 Glide ........................................................................... 23 PUll out/Initiation of Kick .................................................. 25 Review Summary ............................................................ 26 Chapter 3: Methods ................................................................... 28 Subjects ....................................................................... 28 . Subject Preparation ......................................................... 28 Protocol ....................................................................... 28 Kinematic Data Collection ................................. , ............... 29 Analysis of Data ............................................................. 29 Chapter 4: Results .................................................................... 31 Chapter 5: Discussion ................................................................ 39 Tuck Index .................................................................... 39 Foot-Plant Index ............................................................ 42 Wall Contact Time ...... '............. .' ...................................... 43" Chapter 6: Practical Applications ........................................................ 44 Appendices ......................................... .'................................... 45 Appendix A .................................................................. 45 Appendix B .................................................................. 47 References ............. , ................................................................. 48 iii Acknowledgements My most sinc~re thanks go to Dr. Prins for his initiative with this project, his professionalism, and his encouraging "can-do" attitude. I especially appreciated his hands-on work With the data. collection, including coUntless hours spent at the aquatic complex'in the hot sun. ( , Without the help of Dr. Uyeno, the statistical analysis would have not been nearly as thorough and professional. His'support in this area was invaluable. ,-, ., I'd also like to acknowledge Coach Mike Anderson, as well as the UH swimmers who participated in the study. The project wouldn't have been possible without ilieml 1 r •. • Coop provided constructive editing throughout the writing process. My sister Ellen ~ ·4 provided valuable editing feedback from the point of view of a non-swimmer. I'd finally like to thank Steven for encouraging me and supporting me through the final phase of this project. • • IV • Abstract . The purpose ofthis study was to examine the effect of three vanables on the push-off velocity ofthe freestyle flip-turn. These variables are: (l)The distance from the wall a swimmer's hips are at foot contact (tu'ck index); (2) The depth, of the foot plant on the wall during push-off (fodt plant index); and c:h The jJercentage of wall-contact time spent in an active push-off phase (%WCT active). The flip-turns of twenty-three University (Divison I) swimmers performed at race pace were captured using underwater videography and analyzed for kinematic data. Simultaneous regression analysis was conducted using the push-off velocity as a dependent variable to determine the overall predictive characteristics of the variables. The mean push-off velocity was 2.47 ms·!. The minimum velocity ~as 1.3 ms·! and the maximum push-off velocity was 3.29 ms·!. The mean tuck index of all turns was 0.57 +0.14, indicating that the hips were a mean • distance from the wall that was approximately 57% of the length of the swimmer' s l~gs . The study found a significant, negative correlation between push-off velocity and tuck • ,index, indicating that the more tucked position (lower tuck index) predicted higher push- , . off velocity. By using a curvilinear model, a tuck index of.46 was suggested to produce the maximum push-off velocity. Neither'foot plant index nor %WCT active was found to signifi~antly predict push-off velocity. .' • v • " List of Tables and Figures Table " 1. Importance of Turns in Races ..... ; ................................ : .......... '10 2. Push-Off Segment of Turns ................................................... 23 I 3. Means, Maximums, Minimums for Individual Variables ................ 31 '., ~ 4. Skewness and Kurtosis of Data Distribution. .. .. .. .... .. .. .. ..... 31 5. Pearson Product Moment Correlation Matrix ................. : ............. 32 6. Full-Model Simultaneous Regression Analysis Model .................... 32 7. Results of Simultaneous Regression .......................................... 33 • 8. F-Test Full Model ............................................................... 33 9. Coefficients for Push-Off Velocity ............................................ 34. " 10. Collinearity Statistics .............................................. .'............ 34 11: Results of Simple Regression ................................................... 34 12. Analysis Using Tuck Index as Sole Independent Variable ................. 35 'Oc 13. Coefficients for Tuck Index ................................................... 35 14. Descriptive Statistics: Centered and Squared Centered Tuck Index ....; 36 , 15. Linear and Quadratic Models ................................................. 36 ., , 16. Coefficients for Models 1 and 2 ...... : ....................................... 37 17. Results Using a Curvilinear Model ........................................... 37 Figure 1. Tuck Index and Push-Off Velocity .......................................... 36 vi .. • Introduction I. The turning techniques used in swimming competitions playa critical role in the final outcome of the race. Turns comprise up to one'-third of the total race time in Collegiate Short-Course events (Thayer & Hay, 1984). Due to the performance of twice .. as many turns in short course events, the world records for short-course meter events are , considerably faster than the records for,the same distance in a long-course format. Investigations of turris during Olympic swimming competitions demonstrate,the importance of turns in the long course format as well. An analysis of swimmers in the " 1992 Olympic Games has shown that the tu~ing phase of the race is strongly correlated to swimming performance of the 100 and 200 meter Freestyle events (Arrellano, Brown, Cappaert, & Nelson, 1994). In the 2000 Olympic Games in Sydney, Australia, the • performances of finalists and semi-fmalists' in the 200 meter events were studi~d for start phase, velocity, stroke frequency, stroke lengths, and turns. The final event times were related to the velocity of the second and_third length, as well as the velocities of all three turns. The velocity of the. ,final tum was a factor differentiating between medallists and non-medallists. (Chatard, Girold, Caudal, Cossor, & Mason, 2003) The portion of swimming excluding the start and turns is known as "mid'pool swimming." While mid-pilolswimming velocity is the primary determinant of race performance at the elite level (Thayer & Hay, 1984; Mason, 1999; Thompson, Haljand, &