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

Swimmers Improved Much Faster Than RunnersSwimmers Improved Much Faster Than Runners

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

Ages of world recordsAges of world records

11 women’s world records 11 women’s world records are more than 20 yrs oldare more than 20 yrs old

2 men’s records2 men’s records are more than 20 years oldare more than 20 years old

The Triathlon is The Triathlon is Biased !Biased !

Winner spent 16.7% of the time swimming, 28.3% running, Winner spent 16.7% of the time swimming, 28.3% running, 0.8% in transitions, and 54.2% cycling0.8% in transitions, and 54.2% cycling !

The Equitempered The Equitempered TriathlonTriathlon

Roughly equal time on each disciplineRoughly equal time on each disciplineCurrent eventCurrent event

1.5 km swim + 40 km bike ride +10 km run1.5 km swim + 40 km bike ride +10 km run

Better to keep the total time roughly the same – say 1 hr 48m Better to keep the total time roughly the same – say 1 hr 48m with equal 36 min time on each of the three stages with equal 36 min time on each of the three stages

New event should beNew event should be

3 km swim + 24 km bike ride + 12 km run3 km swim + 24 km bike ride + 12 km run

A Major Improvement !A Major Improvement !

Don’t try this at home!Don’t try this at home!

Phillipe Petit, 1974Phillipe Petit, 1974

Why Carry Do Tightrope Walkers CarryWhy Carry Do Tightrope Walkers CarryLong Poles ?Long Poles ?

…….and don’t wear bell-bottomed trousers.and don’t wear bell-bottomed trousers

• High inertiaHigh inertiaSlow to moveSlow to move

• Low inertiaLow inertiaQuick to moveQuick to move

Mass Mass MMAverage radius Average radius RRmass spreadmass spread CC

Moment of Inertia = C Moment of Inertia = C Mass Mass (Radius) (Radius)22

InertiaInertia

high low

Large inertia means you wobble more slowlyLarge inertia means you wobble more slowly

Period of wobble oscillation Period of wobble oscillation (inertia)(inertia)

StableStable UnstableUnstable

Inertia in SportsInertia in Sports

DiversDivers SkatersSkaters Tennis playersTennis players CyclistsCyclists Runners Runners

Decreasing inertiaDecreasing inertiaIncreases rateIncreases rate

of spin: of spin: 1/r 1/r22

Rigging Rowing EightsRigging Rowing Eights

Rowing Has Its MomentsRowing Has Its Moments

+N

-N

FF and

Moment on boat = -Ns + N(s+r) - N(s+2r) + N(s+3r) = +2Nr

Then, half a stroke later…N reverses to –N and..

Moment on boat = -2Nr

The Wiggling BoatThe Wiggling Boat

s

Moment = -Ns + N(s+r) + N(s+2r) - N(s+3r) = 0

The Italian RigThe Italian Rig

No wiggle!

s r r r

Four no-wiggle rigs for eightsFour no-wiggle rigs for eights

‘Italian tandem RigItalian tandem Rig ’

‘‘German Rig’German Rig’

Moment = 1-2-3+4+5-6-7+8 = 0

Moment = 1-2-3+4-5+6+7-8 = 0

Moment = 1-2+3-4-5+6-7+8 = 0

Moment = 1+2-3-4-5-6+7+8 = 0

New*New*

New*New*

Canada used the German rig to win 2008 Olympics !Canada used the German rig to win 2008 Olympics !

1-2+3-4-5+6-7+8 = 0

Naim Suleymanoglu (b.1967) lifts 3 times his body weight (= 64kg)Naim Suleymanoglu (b.1967) lifts 3 times his body weight (= 64kg)

Weight ClassesWeight ClassesWhy do we have them in Why do we have them in

boxing, wrestling, judo and weightlifting?boxing, wrestling, judo and weightlifting?

But not inBut not inShot put, hammer, rowing, …..?Shot put, hammer, rowing, …..?

Why not height classes in high jump and basketball?Why not height classes in high jump and basketball?

Strength versus SizeStrength versus SizeStrength is proportional to area Strength is proportional to area RR22

Weight is proportional to volume Weight is proportional to volume R R33

Strength and WeightStrength and Weight

strength strength (weight) (weight)2/32/3

Giants eventually break!Giants eventually break!

(strength)(strength)33 (weight) (weight)22

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

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(V - W) V(V - W)22

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

K(V-W)K(V-W)22

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

K(V+W)K(V+W)22

K(VK(V22+W+W22))K(VK(V22+W+W22)) DragDrag

round square round square tracktrack

Drag Force per lap = 4K(VDrag Force per lap = 4K(V22 + W + W22) ) 4KV 4KV22 K = constant K = constant

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

Steady Pace Is Always More Steady Pace Is Always More EconomicalEconomical

Go at speed U for dist x then at W = Go at speed U for dist x then at W = U for dist y = x/U for dist y = x/oror

Go at speed ½ (U + W) for dist x+ y in the same time so Go at speed ½ (U + W) for dist x+ y in the same time so = 1 = 1

Work needed Work needed ( speed) ( speed)3 3 time time

(Work at varied pace)(Work at varied pace)(Work at steady pace)(Work at steady pace)

y at Wy at Wx at Ux at U

x + y at ½ (U + W)x + y at ½ (U + W)Same speed all the way Same speed all the way

Change speedChange speed

= 1 + 3(= 1 + 3( - 1) - 1)22/ (/ ( + 1) + 1)22 1 1

The VelodromeThe Velodrome

Heated air at track levelHeated air at track level

MeansMeansFaster cyclingFaster cycling

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

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

Just like an ‘altitude-assisted’ performanceJust like an ‘altitude-assisted’ performanceWorth 1.5 sec over 4K pursuitWorth 1.5 sec over 4K pursuit