03/11/2017. Critical Determinants of Sprint Hurdle Performance. Dr Paul Brice Consultant Biomechanist. Applied Biomechanical Support Track + Field

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1 Critical Determinants of Sprint Hurdle Performance Consultant Biomechanist Applied Biomechanical Support Track + Field Very Simple Approach: To provide coach / athlete / practitioner with objective biomechanical (event specific) information / data...on the critical determinants of performance within both the training and competition environments What it clearly is NOT. the nice to knows or the personal area of interests or the measurement of random stuff But What IT IS. The event specific biomechanical variables that directly impact on PERFORMANCE 1

2 Concept of Critical Determinants of Performance model (CDP) Reduce subjective opinion..all heard them.. Shape of their life Lifting PB s in the gym Amazing workout.. Cant believe what I see in training YET in reality athlete doesn t run faster, jump higher, throw further.. Unlucky, weather was bad, wrong lane, wrong spikes, didn t feel well, couldn t do what they do in training etc etc Understand the Cause and Effect relationships in your event At its worst If science is NOT your thing then at worst it should simply allow a sensible conversation about performance Shape / guides the direction to maximise impact Most people can do this Much harder to do this and do it well 2

3 What do we know: Men s 110mh Men s hurdles 110m race distance 10 hurdles 3 feet 6 inches or 1.07m First hurdle 13.72m from start line, then 9.14m in between hurdles and then 14.02m final hurdle to finish line Current World Record Aries Merritt seconds 7 th September Brussels 2012 What do we know: Women s 100mh Women s hurdles 100m race distance 10 hurdles 2 feet 9 inches or 83.8cm First hurdle 13.00m from start line, then 8.50m in between hurdles and then 10.50m final hurdle to finish line Current World Record Kendra Harrison seconds 22 nd July 2016 London Start with performance and work backwards Race profile Informs coaching decision Greatest return for your investment Target the areas of performance improvement Rather than what you think / believe / or have been told might help.. 3

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5 W100mh RACE PROFILE: WORLD RECORD Race profiles what do they tell us? 5

6 Touchdown to H1 Men sub 2.60 secs Women sub 2.55 seconds Touchdown intervals Men Below 1.00 seconds by H5 Women Below 0.95 seconds by H6 Clearance times Men below seconds Women below seconds Time in between Men below seconds Women below seconds H10 to finish Men below 1.35 seconds Women below 1.05 seconds Horizontal Velocity (m/s) 8.99 Women Men Athlete Good Average Poor 6

7 Key areas #1 Block start to H1 #2 take off pre hurdle #3 Touchdown post hurdle #4 3 steps in between each hurdle Blocks to H1 Step profiles into H1 from blocks w100mh 0.71m, 1.35m, 1.57m, 1.70m, 1.83m, 1.98m, 1.90m m110mh 0.76m, 1.42m, 1.63m, 1.78m, 1.93m, 2.08m, 2.01m 7 th step HAS to be Smaller than 6 th step! 8 th step HAS to be smaller than 7 th step! 7

8 Speed from Optojump 2016 Ground contacts from Optojump 2016 Step Lengths from Optojump

9 Poor Average Good Poor Average Good 03/11/2017 Flight Time from Optojump 2016 Step Length Before and After Hurdle (metres) Women Women Women Before After total Step Length Before and After Hurdle (metres) Men Men Men Before After total 9

10 Flight Time over Hurdle (seconds) Women Men Athlete Good Average Poor Myths and misconceptions Diving into the hurdle is faster Trunk leading the movement is faster Biggest technical issue to resolve but has potential greatest performance improvement Over rotation Problem 1 Starts with what you do into the hurdle take off Prevent upper body diving into the hurdle Upright trunk flexed thigh Segments rotated down and up NOT forward 10

11 Over rotation Problem 2 Once over rotation is started at take off it remains throughout whole clearance time Effects the height of clearance Also results in higher rear leg path Increases time taken to get feet back on floor post landing Over rotation Problem 3 Athlete falls from a higher height Larger forces at impact Trail leg actually moving upwards still over the hurdle Delays ability to attack the ground Lead leg is ankle dominant not thigh The ideal. Tightly compress body around the COM Lower body height path relative to hurdle Small differences make huge difference 0.01 x10 hurdles = 1/10 th second faster!! 11

12 The height factor tall athletes do have advantage How to solve a maths puzzle: Set distance between hurdles 8.5m Have to do 3 steps First one short 2 nd one longer to prepare for take off of next step into hurdle 3 rd one shorter than one before Faster hurdle intervals as race progresses to below 0.95 secs How to keep the Rhythm 8.5m the MAGIC number But it isn t really.. 8.5m minus 0.95m (landing distance post hurdle) minus 1.95m (take off distance pre hurdle) Equals 5.45m to get 3 steps. First step off hurdle 1.40m to 1.58m leaves 4.05m for 2 steps 2 nd step between 2.05 to 2.18m leaves 2.00m for one step 3 rd step between 1.95 to 2.05m 12

13 How do you get faster if cant change the distance between hurdles Velocity = SL x SF SF made up of ground time and flight time Rhythmical event 2 reasons to reduce time in air Slows the athlete down Reduces ability to maintain step frequency But only way to effect velocity is by altering SF Pattern: Short LONG - Short Men 3 step in between hurdle step lengths step step step poor average good 13

14 Women 3 step in between hurdle step lengths step step step poor average good The take off and clearance Active aggressive take offs Thigh leads the movement NOT the ankle Knee separation distance low Promote thigh in front of body action of running Upper leg comes to the trunk not trunk to upper leg Men and Women Trunk Angles Touchdown, Take off and Max flexion Maximal Flexion Hurdle Take Off Hurdle Touchdown Hurdle poor average good 14

15 Submaximal running done maximally Front side dominant running Thigh speed first and then lower leg Attacks ground late swing but also duration of ground contact Especially important step TD and step 3 TO Free knee is level or past stance knee by MKF Better athletes move thigh and lower leg faster in relation to the ground Less braking forces landing distance closer to body Upper Leg Speed 3 steps in between hurdles step 3 contact step 3 TD step 2 contact step 2 TD step 1 contact step 1 TD poor average good Men and Women: Lower Leg Speed OFF the Hurdle Women contact Women touchdown Men contact Men touchdown poor average good 15

16 Women Horizontal foot distance at touchdown 3 steps in between hurdles hurdle step step step poor average good Men Horizontal foot distance at touchdown 3 steps in between hurdle hurdle step step step poor average good Airtimes LOW Ground Contacts LOW Step Frequency HIGH 16