Sports Injuries Lecture 4 - Ankle Sprain

bethdrysdale94's version from 2017-01-16 11:51


Question Answer
What sports have high incidence of ankle sprain?rugby, football, handball, basketball, volleyball
Name some intrinsic risk factors of ankle sprainPrevious sprain, overweight, foot size (increased width), ankle instability, reduced dorsiflexion range
Name some extrinsic risk factors of ankle sprainLack of stretching before exercise, artificial turf use, positions in basketball and football, high top shoes
What is the aetiology of ankle sprain?incorrect landing - foot positioning during touch down. ground reaction force points medially, does not pass through joint centre creating a twisting torque. Causes ankle inversion. "an increased supination moment at subtalar joint resulted from the medially deviated vertical ground force.
Why does increased supination and plantarflexion cause more ankle sprains during touch down?Increased size of moment arm (ground reaction force)
When landing from a jump, what time frame does ankle sprain occur in?40ms as vertical ground reaction force peaks at 40 ms
Why doesn't the peroneal muscle reaction prevent ankle sprain?Reaction time takes longer than 40ms (time of sprain) - sudden inversion during dynamic walking = 74ms, with ankle instability it takes longer. Human reflex is not fast enough to accommodate sudden explosive motion in an inversion sprain
What is the mechanism of supination sprain injury?ankle inversion and plantarflexion, plus internal twisting of the foot.
What are the two major mechanisms of sprain in football?Impact on medial aspect of leg just before or after foot strike, causing ankle inversion OR forced plantarflexion when player hits opponents foot during shot of ball
What torque values are required for ankle sprain?4.3 Nm begins ATFL tear. 41-45 Nm results in total ankle ligament rupture
What are the consequences of repeated ankle sprains?74% have persisting symptoms 1.5-4 years post injury. 10-30% have chronic symptoms (tendinitis, stiffness, swelling, pain). 1-4 sprains = pain is major symptom. 5+ = ankle instability
What categories can chronic ankle instability be divided into?Mechanical and Functional. Mechanical may lead to functional, but functional can exist in the absence of mechanical
What is mechanical ankle instability?abnormal laxity of the ligamentous restraints
What is functional ankle instability?normal ligamentous restraints but abnormal function with recurrent episodes of ankle giving-way
What may lead to ankle osteoarthritis?prolonged translational movement between tibia and talus - may need ankle replacement surgery
What do prophylactic devices help improve?Mechanical support, proprioception, maintenance of vertical anatomical position during landing
What kind of technique training is provided in volleyball?"attack and block" - jump take off vertically, avoid landing under net, on other players etc. landing skills eg rolling, falling, two foot landing
What rule did FIFA introduce in football to help prevent ankle injuries?Tackling from behind is an automatic red card offence

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