The Biomechanics of a Shaposhnikova The Impact of
The Biomechanics of a Shaposhnikova: The Impact of a K-constant Laura Di. Paolo April 19, 2012 Bio 438
Springs and Gymnastics
Uneven Bars • Yeager • Ginger • Tkachev • Shaposhnikova
Muscles Involved in a Shaposhnikova
My Research Questions: ¡How much potential energy is stored in the high bar during a major release? ¡ Ex. A Shaposhnikova ¡How much energy is lost in a Shaposhnikova? ¡ Considerations ¡How does this impact performance? ¡ Adjustments ¡ Testing the Bar
The Shaposhnikova (shaposh)
Marking Movement: COM ¡Center of Mass: the point of balance ¡ Formula For a two mass system: ¡ X (cm) = (m 1 X 1 + m 2 X 2) / (m 1 + m 2) ¡Study by Dr. Glen Elert: “The Center of Mass of a Human” puts the average person’s center of mass at a location slightly below the belly button.
Ratio: Center of Mass to Height http: //hypertextbook. com/facts/2006/centerofmass. shtml
Following my movement: • The Average is about a 0. 55 ratio • 0. 55 of my height comes to the place just above my hip (marked with athletic tape)
Position vs. Time of COM
Potential Energy ¡Gravitational Potential Energy: ¡ PE= mgh ¡Spring Potential Energy: ¡ Hook’s Law ¡ F= - KX ¡ PE= ½ KX 2
Change in Gravitational Potential Energy: ¡ Point 1: ¡ Point 2: ¡ PE= mgh ¡ PE= (54. 4310 kg) (9. 8 m/s 2) (1. 92 m) ¡ PE= (54. 4310 kg) (9. 8 m/s 2) (2. 07 m) ¡ PE= 1024. 17 Kg *m 2/S 2 ¡ PE= 1104. 19 Kg *m 2/S 2 ¡ PE=1. 02417 KJ ¡ PE=1. 10419 KJ Change in PE= 80. 02 J
What does this mean? ¡This is the change in potential energy as a result of 2 factors: ¡Added elastic potential energy from the bar ¡Lost energy in muscles, heat, the bar moving the wrong way (Ex. Trampoline) ¡Back to the research Questions: ¡ How much potential energy is stored in the high bar during a major release? ¡ How much energy is lost in a Shaposhnikova?
Question 1 Part 1: Finding the K constant ¡Hooke’s Law ¡F= -K*ΔX ¡ma = -K*ΔX ¡(54. 4310 kg) (-9. 8 m/s 2)= -K*ΔX ¡ 533. 424 kg*m/s = K*ΔX SO, WHAT’S “ΔX”?
Question 1 Part 1: Finding the K constant ¡ΔX= measured in Logger Pro
Question 1 Part 1: Finding the K constant ¡Displacement (ΔX): ΔX 1= 0. 087 m
Question 1 Part 1: Finding the K constant ¡K Constant (Kg/s 2): ¡ K= ma/ΔX ¡ K= (533. 424 kg*m/s 2) /0. 087 m ¡ K=6131 kg/s 2
Question 1 Part 2: Finding the Elastic Potential Energy PE= ½ KX 2 ΔX=0. 261 m
Question 1 Conclusion: ¡ PE= ½ KX 2 ¡ PE=1/2 * (6131. 3 kg/s 2) * (0. 261)2 m ¡ PE=208. 8 kg*m 2/s 2 PE= 208. 8 J of energy stored in the bar – this is the increase I should have seen in potential energy if I didn’t lose any energy. 2004 Olympian Tasha schwikert
Question 2: How much Energy is Lost?
Question 2: Conclusion ¡I gained 80. 02 J, but lost energy ¡Considerations: ¡ Heat ¡ K-constant calculation: difficulty associated with clicking accuracy. ¡ Pulling back on the bar: reaction of the bar. (Ex. Trampoline) ¡ Center of mass
Another Look… 1. Pulling back on bar during the catch 2. COM
Center of Mass • • • Cannot be avoided because must pass the low bar My center of mass is not actually at my hip as I clear the low bar. The center of mass is returns to my hip in the back-swing. This breaking of my body position makes me lose “swing”– actually a technique to slow yourself down in other bar skills • “Killing the swing” • Energy is dispersed arms, shoulders, abdominal muscles
Question 3: Impact on Performance ¡ I gained 80. 02 J energy from the bar! ¡ Why is this helpful? ¡ Need to be within 10° of horizontal ¡ The more energy from the bar, the less energy must be transferred to the swing from the body by “tapping” ¡ How it impacts performance? ¡ Adjustments: NO universal K constant ¡ High K constant less bar movement “tighter bar” more internal work needed by athlete ¡ Lower K constant more bar movement “loose bar” athlete must remain “tight” and perform less internal work ¡ Testing the bar
Literature ¡ “The amount of energy stored in the bar is proportional to the deflection of the bar. Not all the energy stored in the bar will be returned and so the gymnast needs to input some extra energy from his muscles to compensate for this loss. A 'springy' bar is beneficial in a number if ways” (Kerwin 2005) *study published in 2003 ¡ “Gymnasts have a tendency to pike in the front of the swing to get their feet above the bars. This ends up killing the swing” (“Drills and Skills”) ¡ Varying the tension in the stabilizing cables of the high bar did not affect the stiffness of the bar (Kerwin 2003). ¡ Horizontal movement
Future Studies ¡ Varying the K-constant: Performing the skill on different equipment ¡ different age, AAI vs. Speith ¡ Comparing the energy loss with my shaposh and someone who is short enough to maintain a straight body position ¡ Closer look at energy loss here ¡ Measure differences in energy loss and angle of the “rounded” or “piked” position ¡ Compare men and women’s high bars Jordyn Weiber #1 Prospect for 2012 Olympic Games
References ¡ "Center of Mass. " Web. 2 Apr. 2012. <http: //hyperphysics. phy-astr. gsu. edu/hbase/cm. html>. ¡ "Center of Mass. " Web. 2 Apr. 2012. http: //hyperphysics. phy-astr. gsu. edu/hbase/cm. html. ¡ Elastic Potential Energy. " Web. 2 Apr. 2012. <http: //hyperphysics. phy-astr. gsu. edu/hbase/pespr. html>. ¡ Kerwin, D. G. , and M. J. Hiley. "Estimation of Reaction Forces in High Bar Swinging. " Sports Engineering 6. 1 (2003): 21 -30. Loughborough University. Springer / © ISEA. Web. 25 Mar. 2012. <https: //dspace. lboro. ac. uk/dspace-jspui/handle/2134/6528>. ¡ Kerwin, David. "Swinging in Gymnastics. " Swinging in Gymnastics Info. com, 2005. Web. 14 Apr. 2012. <http: //www. coachesinfo. com/index. php? option=com_content&view=article&id=10199: gymnastics-isbsswinging&catid=183: mens-high-bar&Itemid=290>. ¡ "Mass of a Human Head. " Hypertextbook. com. Ed. Glenn Elert. Web. 2 Apr. 2012. http: //hypertextbook. com/facts/2006/Dmitriy. Gekhman. shtml. ¡ "Parallel Bars Drills and Skills. " Gymnastics Page. Web. 14 Apr. 2012. <http: //www. drillsandskills. com/skills/pbar/>.
References Images: ¡ http: //aura. nswebhost. com/~ballet/images/Spring-Floors. jpg ¡ http: //www. american-gymnast. com/shop/Assets/Product. Images/aai_T 10_Vault_Spring_Board. jpg ¡ http: //www. gymn. ca/gymnasticgreats/images/wag/shaposh. jpg ¡ http: //www. unitedathletic. com/images/UAI%20 CLUB%20 BARS%20 WITH%20 MATS. jpg ¡ http: //hyperphysics. phy-astr. gsu. edu/hbase/pespr. html ¡ http: //content. clickbooq. com/86/photos/6 bc 6 a 5 a 809. jpg ¡ http: //johngeddert. com/wp-content/uploads/2010/11/Uneven-Bars. jpg http: //laist. com/attachments/la_adam 1/tashaschwikert. jpg ¡ http: //gymnasticscoaching. files. wordpress. com/2009/06/gymnast-chalking. jpg ¡ http: //3. bp. blogspot. com/_1 rmy. Hr. Vm 294/TKNVCl. TL 04 I/AAAAACI/ehsy. Wd. L 6 Zy 4/s 160 0/trampoline. gif ¡ https: //usagym. org/pages/home/publications/technique/2008/10/cover_lg. jpg ¡ http: //www. medicalook. com/systems_images/Muscles_of_the_Abdominal_Wall. jpg ¡ http: //www. getbodysmart. com/ap/muscularsystem/armmuscles/menu/image. gif
- Slides: 28