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Page 1: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

How Fast Can How Fast Can Usain Bolt Run?Usain Bolt Run?

John D BarrowJohn D Barrow

Page 2: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

World 100m record progression: menWorld 100m record progression: men

Page 3: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Swimming Improvements are Vastly GreaterSwimming Improvements are Vastly Greater

Men’s 400m run: 43.8 (1968) to 43.18 (2011)Men’s 100m swim: 52.2 (1968) to 46.91 (2011)

Page 4: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Bolt’s 100m Record-breaking Bolt’s 100m Record-breaking ProgressionProgression

2008 Beijing Olympics 2008 Beijing Olympics 9.68 s9.68 s

2010 Berlin World Championships 2010 Berlin World Championships 9.58 s9.58 s

Page 5: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Final Time = Reaction Time + Run TimeFinal Time = Reaction Time + Run Time

Reaction Time less than +0.10 s = 100 millisecsReaction Time less than +0.10 s = 100 millisecsMeans a false start andMeans a false start and

Disqualification Disqualification

Reaction time -0.104 s (before the gun!)

Page 6: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

The straight 200m timekeeping problem The straight 200m timekeeping problem

sound travel time was 1.7s. sound travel time was 1.7s. Timekeepers reacted to the visual flash – not the soundTimekeepers reacted to the visual flash – not the sound

The ‘Gun’ is Not Good EnoughThe ‘Gun’ is Not Good Enough

+ Starter’s position

5m

15m

Sound speed = 340 m/sSound speed = 340 m/s

Inside lane hears the gunInside lane hears the gun

(15 -5)/340 = 0.029s(15 -5)/340 = 0.029s

earlier than outside laneearlier than outside lane

This really matters!This really matters!

Page 7: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Armin Hary reaction 0.04s!!

1960 Olympic Champion1960 Olympic Champion(was very suspicious)(was very suspicious)

The ‘Anticipator’The ‘Anticipator’

Page 8: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Berlin World ChampionshipsBerlin World Championships

Bolt 0.146 + 9.434 = 9.58 Gay 0.144 + 9.566 = 9.71 Powell 0.134 + 9.706 = 9.84 Bailey 0.129 + 9.801 = 9.93 Thompson 0.119 + 9.811 = 9.93 Chambers 0.123 + 9.877 = 10.00 Burns 0.165 + 9.835 = 10.00 Patton 0.149 +10.191 = 10.34

Beijing Olympic final: Bolt’s 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.

Page 9: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

425 athletes. Male mean 168 ms with 160-178ms 95% CLFemale mean 191 ms with 180-205 ms 95% CL

Estimated absolute min for male 124 ms, for female 130 msMale sprinters made 25 false starts in Beijing -- only 4 by females

DB Lipps et al

Quickest possible reaction is supposed to be 100 msQuickest possible reaction is supposed to be 100 ms

Page 10: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Should there be different false start criteria Should there be different false start criteria for men and women??for men and women??

Page 11: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

False starting is not the AnswerFalse starting is not the Answer

Page 12: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Improvement Tip Number 1Improvement Tip Number 1Improve reaction time to 0.12 s and Improve reaction time to 0.12 s and

9.58 s record improves to 9.58 s record improves to 9.55 s9.55 s

Improve reaction time to 0.10 s and Improve reaction time to 0.10 s and

9.58 s record improves to 9.58 s record improves to 9.53 s9.53 s

Page 13: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Wind AssistanceWind Assistance

Page 14: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Streamlining and Effective Body AreaStreamlining and Effective Body Area

Page 15: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Area, A(Bolt)

Mass of tube of air swept in time t is Mass of tube of air swept in time t is A’ A’ V V t = t = mmaa

= air density = air density A’ = c A’ = c A(runner) is the ‘effective’ body area A(runner) is the ‘effective’ body area

c = drag factorc = drag factor

Drag force from still air = -mDrag force from still air = -maaVV /t /t = -= - c A V c A V22

Drag force with wind speed W = Drag force with wind speed W = -- c A (V c A (V - - W)W)22

Following wind is Following wind is ++ and Headwind is and Headwind is ––

Speed V

Air DragAir Drag

Page 16: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Drag force with wind speed W is Drag force with wind speed W is (V - W) (V - W)22

Power needed = Force x velocityPower needed = Force x velocity (V - W) (V - W)2 2 xx VV

Following wind is + and Headwind is –Following wind is + and Headwind is –

Disadvantage of headwind and crosswind beats Disadvantage of headwind and crosswind beats the advantage of a tailwind of the same magnitudethe advantage of a tailwind of the same magnitude

Running around in the WindRunning around in the Wind

Wind speed W in this directionWind speed W in this direction

KV(V-W)KV(V-W)33

Runner runs at speed V in still airRunner runs at speed V in still air

KV(V+W)KV(V+W)22

KVKV (V(V22+W+W22))KV(VKV(V22+W+W22))

LapLapof square of square

tracktrack Power per lap = 4KV(VPower per lap = 4KV(V22 + W + W22 ) ) 4KV 4KV33

It’s always slower running laps in the windIt’s always slower running laps in the wind Windy 400m- 10,000m races will be slowerWindy 400m- 10,000m races will be slower

Page 17: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

A Wind-assisted MarathonA Wind-assisted Marathon

““It felt like there was no wind” It felt like there was no wind” V = W V = WDrag force with wind speed W is -Drag force with wind speed W is - c A (V - W) c A (V - W)22

April 18April 18thth 2011 2011 Geoffrey Mutai 2 hrs 3m 2s Boston marathon (Moses Mosop 4 s behind)Geoffrey Mutai 2 hrs 3m 2s Boston marathon (Moses Mosop 4 s behind)Downhill point-to-point courses can’t drop more than 42 m. Boston drops 139 m ! Downhill point-to-point courses can’t drop more than 42 m. Boston drops 139 m !

Winner’s average speed 5.7 m/s -- close to estimates of following wind on the course Winner’s average speed 5.7 m/s -- close to estimates of following wind on the course 3% power saving3% power saving

Equivalent to a still-air time of Equivalent to a still-air time of 2 hrs 6m 45s2 hrs 6m 45s with the wind always at his back. with the wind always at his back.Bunched for first half so maybe only had benefit for second half (run in 61m 04s !!!)Bunched for first half so maybe only had benefit for second half (run in 61m 04s !!!)

This gives a corrected time of 2hr 4m 52sThis gives a corrected time of 2hr 4m 52s.

Current record is 2:03:38, set by Patrick Makau on 25 Sept. 2011 Current record is 2:03:38, set by Patrick Makau on 25 Sept. 2011 Haile Gebrselassie’s old world record was 2hr 3m 57sHaile Gebrselassie’s old world record was 2hr 3m 57s

Page 18: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Allowing for wind assistanceAllowing for wind assistancein the 100m sprintin the 100m sprint

M = 70 kg M = 70 kg = 1.19 kg/m= 1.19 kg/m33

A = 1.8 A = 1.8 0.3 m 0.3 m22

c c 1 1About 3% of effort is beating wind dragAbout 3% of effort is beating wind drag

T(W=0) = [1.03 – 0.03(1 – WT(W)/100)T(W=0) = [1.03 – 0.03(1 – WT(W)/100)22] ] T(W) T(W)

Page 19: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Roughly 2 m/s of following wind reduces windless time by Roughly 2 m/s of following wind reduces windless time by 0.1s 0.1s

Bolt’s 9.58 s was set with W = 0.9 m/sBolt’s 9.58 s was set with W = 0.9 m/sImproves toImproves to

9.49 s with faster reaction time9.49 s with faster reaction timeand a W = +2 m/s tailwindand a W = +2 m/s tailwind

““It’s an ill wind …..”It’s an ill wind …..”Improvement Tip Number 2Improvement Tip Number 2

Page 20: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

The Women’s World RecordThe Women’s World Record

Florence Griffiths JoynerFlorence Griffiths Joynerwas almost certainly wind-assisted!was almost certainly wind-assisted!

‘‘Flo-Jo’Flo-Jo’10.49 s10.49 s????????????

Page 21: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Wind gauge read 0.0 m/s in 1988 US Olympic trials semi-finalWind gauge read 0.0 m/s in 1988 US Olympic trials semi-final

Neighbouring jumps were experiencing 4m/s tailwindsNeighbouring jumps were experiencing 4m/s tailwinds and the next semi-final had 5 m/s tailwindand the next semi-final had 5 m/s tailwind

10.49s broke the record by 0.27s10.49s broke the record by 0.27s !!

A Case of Wind Gauge Failure ?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

Page 22: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Each 1000m of altitude produces a reduction in air density

worth about 0.03s over sea level for 100m sprintersMexico 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 aloneImprovements were much greater than air density effect alone

High-Altitude SprintingHigh-Altitude SprintingImprovement Tip Number 3Improvement Tip Number 3

Page 23: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

The VelodromeThe Velodrome

Heated air at track levelHeated air at track level

MeansMeansFaster cyclingFaster cycling

Page 24: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Air Density Falls with TemperatureAir Density Falls with Temperature

Hot air rises !Hot air rises !Drag force from still air Drag force from still air airair c A V c A V22

(deg K)/T

Page 25: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Air Drag at Track Level in the London VelodromeAir Drag at Track Level in the London VelodromeDrag Force Drag Force airair × frontal area × V × frontal area × V22

A new type of ‘wind-assisted’ performanceWorth 1.5 sec over 4K pursuit

Page 26: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

1. Improve Reaction Time 2. Maximise legal wind assistance to 2 m/s3. Race at high altitude (2250m)

Effortless Improvements for BoltEffortless Improvements for Bolt

Page 27: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Reaction time improvement Reaction time improvement 9.55 s9.55 s

Maximise legal tailwind Maximise legal tailwind 9.49 s9.49 s

Race at max ‘legal’Race at max ‘legal’high altitude (1000m)high altitude (1000m)

9.46 s9.46 s

‘‘Effortless’ Improvements for BoltEffortless’ Improvements for Bolt

His 9.58 s becomesHis 9.58 s becomes

Page 28: How Fast Can Usain Bolt Run? John D Barrow. World 100m record progression: men.

Is Bolt The Fastest?Is Bolt The Fastest?

Blake: 19.26s - reaction time 0.27s = Run time of 18.99s Blake: 19.26s - reaction time 0.27s = Run time of 18.99s Bolt: 19.19s – reaction time 0.13 = Run Time of 19.06s Bolt: 19.19s – reaction time 0.13 = Run Time of 19.06s

Usain Bolt’s average 100m is 9.530sUsain Bolt’s average 100m is 9.530sYohan Blake’s average 100m is 9.495Yohan Blake’s average 100m is 9.495