World 100m running record progression: men

Swimmers Improved Much Faster Than Runners Men’s 400m run: 43.8 (1968) to (2011) Men’s 100m swim: 52.2 (1968) to (2011)

Ages of world records

11 women’s world records are more than 20 yrs old 2 men’s records are more than 20 years old are more than 20 years old

The Triathlon is Biased ! Winner spent 16.7% of the time swimming, 28.3% running, 0.8% in transitions, and 54.2% cycling 0.8% in transitions, and 54.2% cycling !

The Equitempered Triathlon Roughly equal time on each discipline Current event 1.5 km swim + 40 km bike ride +10 km run 1.5 km swim + 40 km bike ride +10 km run Better to keep the total time roughly the same – say 1 hr 48m with equal 36 min time on each of the three stages New event should be 3 km swim + 24 km bike ride + 12 km run A Major Improvement !

Don’t try this at home! Phillipe Petit, 1974 Why Carry Do Tightrope Walkers Carry Long Poles ? ….and don’t wear bell-bottomed trousers

High inertia Slow to move Low inertia Low inertia Quick to move Mass M Average radius R mass spread C Moment of Inertia = C  Mass  (Radius) 2 Inertia high low

Large inertia means you wobble more slowly Period of wobble oscillation   (inertia)

StableUnstable

Inertia in Sports Divers Divers Skaters Skaters Tennis players Tennis players Cyclists Cyclists Runners Runners Decreasing inertia Increases rate of spin:   1/r 2

Rigging Rowing Eights

Rowing Has Its Moments +N -N F F 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 Boat s

Moment = -Ns + N(s+r) + N(s+2r) - N(s+3r) = 0 The Italian Rig No wiggle! s rrr

Four no-wiggle rigs for eights Italian tandem Rig ‘Italian tandem Rig ’ ‘German Rig’ Moment = = 0 Moment = = 0 Moment = = 0 Moment = = 0 New* New*

Canada used the German rig to win 2008 Olympics ! = 0

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

Weight Classes Why do we have them in boxing, wrestling, judo and weightlifting? But not in Shot put, hammer, rowing, …..? Why not height classes in high jump and basketball?

Strength versus Size Strength is proportional to area R 2 Strength is proportional to area  R 2 Weight is proportional to volume  R 3

Strength and Weight strength  (weight) 2/3 Giants eventually break!

(strength) 3  (weight) 2

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

Drag force with wind speed W is  (V - W) 2 Power needed = Force x velocity  V(V - W) 2 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 K(V-W) 2 Runner runs at speed V in still air K(V+W) 2 K(V 2 +W 2 ) Drag round square track Drag Force per lap = 4K(V 2 + W 2 )  4KV 2 K = constant It’s always slower running laps in the wind Windy 400m- 10,000m races will be slower

Steady Pace Is Always More Economical Go at speed U for dist x then at W = U for dist y = x/  or Go at speed ½ (U + W) for dist x+ y in the same time so  = 1 Work needed  ( speed) 3  time (Work at varied pace) (Work at steady pace) y at W x at U x + y at ½ (U + W) Same speed all the way Change speed = 1 + 3( - 1) 2 / ( + 1) 2  1

The Velodrome Heated air at track level Means Faster cycling

Air Density Falls with Temperature Hot air rises ! Drag force from still air   air c A V 2

Air Drag at Track Level in the London Velodrome Drag Force   air × frontal area × V 2 Just like an ‘altitude-assisted’ performance Worth 1.5 sec over 4K pursuit