How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men

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Transcript of How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men

  • Slide 1
  • How Fast Can Usain Bolt Run? John D Barrow
  • Slide 2
  • World 100m record progression: men
  • Slide 3
  • Swimming Improvements are Vastly Greater Mens 400m run: 43.8 (1968) to 43.18 (2011) Mens 100m swim: 52.2 (1968) to 46.91 (2011)
  • Slide 4
  • Bolts 100m Record-breaking Progression 2008 Beijing Olympics 9.68 s 2010 Berlin World Championships 9.58 s
  • Slide 5
  • Final Time = Reaction Time + Run Time Reaction Time less than +0.10 s = 100 millisecs Means a false start and Disqualification Reaction time -0.104 s (before the gun!)
  • Slide 6
  • The straight 200m timekeeping problem sound travel time was 1.7s. Timekeepers reacted to the visual flash not the sound The Gun is Not Good Enough + Starters position 5m 15m Sound speed = 340 m/s Inside lane hears the gun (15 -5)/340 = 0.029s earlier than outside lane This really matters!
  • Slide 7
  • Time Waited Before Green Light vs. Average Reaction Time Reaction times, by month: 2006-12231.7210 2007-01230.2160 2007-02221.5340 2007-03213.5495 2007-04218.2240 2007-05223.5815 2007-06227.9971 2007-07218.9489 2007-08223.1460 2007-09225.2622 2007-10225.6355 2007-11226.1450 2007-12225.0047 2008-01224.1950 2008-02228.6108 2008-03225.5128 2008-04224.1333 2008-05221.8307 2008-06223.8115 2008-07220.1270 2008-08223.6209 2008-09228.1079 2008-10225.6141 2008-11225.1891 2008-12225.3566 2009-01229.3421 2009-02227.8805 2009-03227.0507 2009-04227.6157 2009-05226.7158 2009-06218.5118 2009-07219.2302 2009-08225.1163 2009-09225.8613 2009-10227.8240 2009-11228.3662 2009-12227.8109 2010-01233.3751 2010-02232.7230 2010-03238.8148 2010-04233.1478 2010-05233.6491 2010-06230.2473 2010-07241.0561 2010-08239.1098 2010-09240.2925 2010-10242.6746 2010-11243.6936 2010-12240.3398 2011-01241.4032 2011-02246.1841 2011-03248.7490 2011-04244.2065 2011-05247.0543 2011-06246.5999 2011-07241.3142 2011-08245.9536 2011-09252.5752 2011-10251.1309 Copyright 2006-2010 HumanBenchmark.com Armin Hary reaction 0.04s !! 1960 Olympic Champion (was very suspicious) The Anticipator
  • Slide 8
  • Berlin World Championships Bolt 0.146 + 9.434 = 9.58 Gay0.144 + 9.566 = 9.71 Powell0.134 + 9.706 = 9.84 Bailey 0.129 + 9.801 = 9.93 Thompson 0.119 + 9.811 = 9.93 Chambers0.123 + 9.877 = 10.00 Burns0.165 + 9.835 = 10.00 Patton0.149 +10.191 = 10.34 Beijing Olympic final: Bolts reaction time was 0.165s for his 9.69s total, The other seven finalists reacted in 0.133, 0.134, 0.142, 0.145, 0.147, 0.165, and 0.169 sec. Only one was slower than Bolt.
  • Slide 9
  • 425 athletes. Male mean 168 ms with 160-178ms 95% CL Female mean 191 ms with 180-205 ms 95% CL Estimated absolute min for male 124 ms, for female 130 ms Male sprinters made 25 false starts in Beijing -- only 4 by females DB Lipps et al Quickest possible reaction is supposed to be 100 ms
  • Slide 10
  • Should there be different false start criteria for men and women??
  • Slide 11
  • False starting is not the Answer
  • Slide 12
  • Improvement Tip Number 1 Improve reaction time to 0.12 s and 9.58 s record improves to 9.55 s Improve reaction time to 0.10 s and 9.58 s record improves to 9.53 s
  • Slide 13
  • Wind Assistance
  • Slide 14
  • Streamlining and Effective Body Area
  • Slide 15
  • Area, A(Bolt) Mass of tube of air swept in time t is A V t = m a = air density A = c A(runner) is the effective body area c = drag factor Drag force from still air = -m a V /t = - c A V 2 Drag force with wind speed W = - c A (V - W) 2 Following wind is + and Headwind is Speed V Air Drag
  • Slide 16
  • Drag force with wind speed W is (V - W) 2 Power needed = Force x velocity (V - W) 2 xV Power needed = Force x velocity (V - W) 2 x V Following wind is + and Headwind is Disadvantage of headwind and crosswind beats the advantage of a tailwind of the same magnitude Running around in the Wind Wind speed W in this direction KV(V-W) 3 Runner runs at speed V in still air KV(V+W) 2 KV (V 2 +W 2 ) Lap of square track Power per lap = 4KV(V 2 + W 2 ) 4KV 3 Its always slower running laps in the wind Windy 400m- 10,000m races will be slower
  • Slide 17
  • A Wind-assisted Marathon It felt like there was no wind V = W Drag force with wind speed W is - c A (V - W) 2 April 18 th 2011 Geoffrey Mutai 2 hrs 3m 2s Boston marathon (Moses Mosop 4 s behind) Downhill point-to-point courses cant drop more than 42 m. Boston drops 139 m ! Winners average speed 5.7 m/s -- close to estimates of following wind on the course 3% power saving Equivalent to a still-air time of 2 hrs 6m 45s with the wind always at his back. Bunched for first half so maybe only had benefit for second half (run in 61m 04s !!!) This gives a corrected time of 2hr 4m 52s This gives a corrected time of 2hr 4m 52s. Current record is 2:03:38, set by Patrick Makau on 25 Sept. 2011 Haile Gebrselassies old world record was 2hr 3m 57s
  • Slide 18
  • Allowing for wind assistance in the 100m sprint M = 70 kg = 1.19 kg/m 3 A = 1.8 0.3 m 2 c 1 About 3% of effort is beating wind drag T(W=0) = [1.03 0.03(1 WT(W)/100) 2 ] T(W)
  • Slide 19
  • Roughly 2 m/s of following wind reduces windless time by 0.1s Bolts 9.58 s was set with W = 0.9 m/s Improves to 9.49 s with faster reaction time and a W = +2 m/s tailwind Its an ill wind .. Improvement Tip Number 2
  • Slide 20
  • The Womens World Record Florence Griffiths Joyner was almost certainly wind-assisted! Flo-Jo 10.49 s ??????
  • Slide 21
  • Wind gauge read 0.0 m/s in 1988 US Olympic trials semi-final Neighbouring jumps were experiencing 4m/s tailwinds and the next semi-final had 5 m/s tailwind and the next semi-final had 5 m/s tailwind 10.49s broke the record by 0.27s 10.49s broke the record by 0.27s !! A Case of Wind Gauge Failure ? Real record is 10.61s in the final with +0.9 m/s tailwind Similar dramatic improvements by the others in the same race
  • Slide 22
  • Each 1000m of altitude produces a reduction in air density worth about 0.03s over sea level for 100m sprinters Mexico City was worth about 0.07s Many actual records were improved by 1.7% in Mexico City Improvements were much greater than air density effect alone High-Altitude Sprinting Improvement Tip Number 3
  • Slide 23
  • The Velodrome Heated air at track level Means Faster cycling
  • Slide 24
  • Air Density Falls with Temperature Hot air rises ! Drag force from still air air c A V 2 (deg K)/T
  • Slide 25
  • Air Drag at Track Level in the London Velodrome Drag Force air frontal area V 2 A new type of wind-assisted performance Worth 1.5 sec over 4K pursuit
  • Slide 26
  • 1. Improve Reaction Time 2. Maximise legal wind assistance to 2 m/s 3. Race at high altitude (2250m) Effortless Improvements for Bolt
  • Slide 27
  • Reaction time improvement 9.55 s Maximise legal tailwind 9.49 s Race at max legal Race at max legal high altitude (1000m) 9.46 s Effortless Improvements for Bolt His 9.58 s becomes
  • Slide 28
  • Is Bolt The Fastest? Blake: 19.26s - reaction time 0.27s = Run time of 18.99s Bolt: 19.19s reaction time 0.13 = Run Time of 19.06s Usain Bolts average 100m is 9.530s Yohan Blakes average 100m is 9.495
  • Slide 29
  • How Accurate should the Wind Readings Be? 2 m/s limit derives from accuracy of 1936 hand-timing = 0.1s Records now kept to 0.01 s so need wind accuracy better than 0.2 s Wind gauge is at 50m point and 1.22m above ground and within 2m of the track Unfortunately wind gauge accuracy is only 0.2-0.5 m/s And wind speed varies with position This is a major inconsistency with record criteria
  • Slide 30
  • N. Linthorne
  • Slide 31
  • In Daegu Bolt is off the scale in the wrong sense! + + Bolt Starts before the gun is fired!
  • Slide 32
  • The Running Endurance Equation Men: V d -0.109 Women: V d -0.111
  • Slide 33
  • The Wheelchair Endurance Equation Men: V d -0.006 Women: V d -0.021 No significant fall-off in speed with distance! with distance!