The importance of sagittal kick symmetry for underwater dolphin kick performance
Atkison, R.1,2., Nolte, V.1, Dickey, J.1 & Dragunas A.1 1The University of Western Ontario, London, ON
2Canadian Sport Institute Ontario, Toronto, ON
Basic Mechanics
• Cyclic motion – Up-peak – Down-peak
• 2 Distinct Phases – Downkick (DK) – Upkick (UK)
Rationale
• Experienced swimmers shed large vortices during DK & smaller vortices in UK phases; inexperienced swimmers shed small vortices during DK phase and none during UK (Arellano, 1999; Arellano et al., 2000)
• Dolphins/cetaceans perform symmetrical DK & UK phases (Ungerechts, 1983; Von Loebbecke et al., 2009a; Von Loebbecke et al., 2009b)
Purpose
To evaluate the kinematics of DK and UK phases and how symmetry between DK and UK is related to performance
• 15 male swimmers from University and Club Age = 21.5±3.2 yrs,
Experience = 11.4 ± 5.6 yrs
• Filmed 3 trials of 15m UDK at max effort
• Digitized 12 landmarks
Methods
Measured & Calculated: • vertical joint amplitudes & velocities, • horizontal CM displacements & velocities, • joint angles, & kicking frequencies Each variable determined for whole kick cycle, DK & UK Symmetry ratios determined for each variable (DK/UK) Correlated mean horizontal velocity (Vx) with all DK & UK values, and with symmetry ratios
Methods
Results
Fastest: Vx = 1.84m/s
Median: Vx = 1.67 m/s Slowest: Vx = 1.30 m/s
Additional Findings
Limitations
Conclusions
• Kick symmetry highly related to UDK performance – Those who perform UK well tend to be faster at
UDK
• Factors contributing to UK performance…
– Peak vertical toe velocity – Hyperextended knees and ankles at start of UK, less
knee flexion at end of UK
Further Study
• Low hand amplitudes related to performance – Importance of thoracic mobility – Drag reduction?
• Bilateral asymmetries
• Evidence of trunk undulation
Acknowledgments
Canadian Sport Institute Ontario UWO Swimming
London Aquatic Club Dr. Volker Nolte Dr. Jim Dickey
Dr. Horia Hangan Coach Paul Midgley Andrew Dragunas
Works Cited
Arellano, R. (1999). Vortices and propulsion. In R. Sanders & J. Linsten (Eds.), Applied proceedings of the XVII international symposium on biomechanics in sports: Swimming (pp. 53-65). Perth: Edith Cowan University.
Arellano, R., Pardillo, S., & Gavilán, A. (2000). Underwater undulatory swimming: kinematic characteristics, vortex generation and application during the start, turn and swimming strokes. Coaches' Infoservice [On-line]. Available: http://www.coachesinfo.com/index.php?option=com_docman&task=cat_view&gid=36&Itemid=68
Ungerechts, B. (1983). A comparison of the movements of the rear parts of dolphins and butterfly swimmers. Biomechanics and Medicine in Swimming, 215-221.
Von Loebbecke, A., Mittal, R., Fish, F., & Mark, R. (2009a). Propulsive Efficiency of the Underwater Dolphin Kick in Humans. Journal of Biomechanical Engineering, 131, 054504.
Von Loebbecke, A., Mittal, R., Fish, F., & Mark, R. (2009b). A comparison of the kinematics of the dolphin kick in humans and cetaceans. Human Movement Science, 28(1), 99-112. Elsevier B.V. doi:10.1016/j.humov.2008.07.005
http://www.coachesinfo.com/index.php?option=com_docman&task=cat_view&gid=36&Itemid=68http://www.coachesinfo.com/index.php?option=com_docman&task=cat_view&gid=36&Itemid=68
The importance of sagittal kick symmetry for underwater dolphin kick performance Basic MechanicsRationalePurposeMethodsMethodsResultsSlide Number 8Slide Number 9Additional FindingsSlide Number 11Slide Number 12LimitationsConclusionsFurther StudyAcknowledgmentsWorks Cited
