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Kendra Sickinger. MECHANICS OF Ankle Sprains in Sports. Objectives. Anatomy orientation Surfaces Coefficient of friction Impulse Prevention. What is an ankle sprain?. Stretching or tearing of ligaments surrounding bone Ankle is in unnatural position, uneven surface, “roll in” - PowerPoint PPT Presentation
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MECHANICS OF ANKLE SPRAINS IN SPORTS
Kendra Sickinger
Objectives Anatomy orientation Surfaces Coefficient of friction Impulse Prevention
What is an ankle sprain? Stretching or tearing of ligaments
surrounding bone Ankle is in unnatural position, uneven
surface, “roll in” Grade I, II, III
Anatomy Orientation
Which is more common?
Friction and Forces
Friction is the force that opposes efforts to slide or roll one body over another
Force needed to plant the foot Surfaces with high coefficients of friction
requires large amount of force Higher coefficients leads to more force
to more injuries
Coefficient of Friction Rolling friction helps soccer
players to determine how the ball will react on turf vs. grass
Smaller coefficient, easier for the surfaces to begin rolling or slide
Coefficient of 0.0 would indicate a frictionless surface
Friction is dependent on the force holding the surfaces together and force needed to slide one surface over
Coefficient decreases as f(max) decreases
Why do ankle sprains happen? An unnatural twisting motion Planted awkwardly Ground is uneven Unusual amount of force is applied to the joint Unaware Supporting weight and ankle size
Turf Surface High friction between
cleat and playing surface Greater number of
injuries due to friction Hardness/sticky feeling In 2000 created synthetic
infill artificial surface (eg. FieldTurf, AstroPlay) to create less friction
How this ties to impulseF= m(Vf-Vi)
T
Different surfacesGrass Sand
Speed of play is slower (time)
Landing on softer surface vs. indoor court
Harder to maintain Court rules
Unaware of uneven surfaces
time
F= m(Vf-Vi)T
Gymnastics Surface Padded surface Fast velocities High impact forces Small margin of error Dorsiflex Overuse
Tied To Class
Learned that friction is a force that acts upon opposite direction
Too much friction can cause injury Coefficient gets higher, more friction Increasing friction = better performance
as well as decreasing frictionF= m(Vf-Vi)
TOnly impact on force is time
Prevention Stability/balance exercises Ankle braces Proper shoe Strengthen muscles around ankle Range of motion
Conclusion Turf vs. grass is still controversial Force and friction Friction surface plays a dominate role in
ankle sprains in sports Impulse equation Never 100% prevent
F= m(Vf-Vi)T
References Drakos, M. (2008). Artificial Turf: Does it Increase the Risk of
Sports Injuries? Hospital for special surgery. http://www.hss.edu/conditions_artificial-turf-sports-injury-prevention.asp
Goal-Tek Innovations ltd. Soccer Safety E- Book. Turf Field Hazards (5). http://www.goal-tek.com/SoccerSafety_ch05.asp
Kinesiology: Scientific Basis of Human Motion. 11th ed. New York: McGraw-Hill, 2008. Print.
Nicholas Institute of Sports Medicine and Athletic Trauma (2007) Ankle Sprains. http://www.nismat.org/ptcor/ankle_sprain
Vormittag, K., Calonje, R., & Briner, W. W. (2009) Foot and ankle injuries in the bare sports. American College of Sports Medicine, 8(5).