Some observations on physics and the new Santa Anita dirt track --
>
>
>Physics says force increases as an exponential (actually the square)
>of velocity [ i.e., f = mass*(velocity squared) ].
>
>The faster times we\'re seeing at Santa Anita now, mean more
>multiples of the force (see physics summary below).
>
>Could this possibly mean it will lead to more injuries?
>
>The new 7 furlong record the other day at Santa Anita was 1:19 and change.
>
>According to the Thoroughbred Times Racing Almanac (master racing
>journalist Don Clippinger\'s creation), Spectacular Bid\'s record was
>1:20, and the fastest time in 2007 on the new synthetic was 1:20.37.
>The fastest 7f time on the old dirt track that year was 1:21.11 by
>Latent Heat.
>
> The average force already on a Thoroughbred racehorse leg at 12
> secs per furlong (55 ft per sec) is roughly describable by force
> = mass (1,000 lbs) times velocity (55 ft/sec) squared. (see Nat\'l
> Science Foundation racetrack force plate studies by Kingsbury in the Journal of Biomechanics]
>.
>[note -- the foreleg retracts - goes backwards, before hitting the
>ground so the leg velocity is less at impact than the main inertial
>mass velocity. On the other hand, the faster they go, the more
>extended they are, and the less foreleg retraction before impact.
>The rear legs really don\'t have that sort of retraction.]
>
> Changing from about 1:22 for seven furlongs to 1:19 is a change
> of 3 seconds overall, or probably at least 1 sec per furlong of
> velocity somewhere in the race.
>
>Go 1 second per furlong faster and the overall velocity is about 5
>ft/sec faster. So, for example, if you go 1 sec per furlong faster,
>instead of a velocity of 55 ft/sec, you\'d have 60 ft per second. Put
>that into the force equation above. 55 squared is 3,025 times the
>mass = force. 60 squared is 3,600 times the mass = force.
>That is 575 times more units of force possible.
>
>Yes, Santa Anita\'s new track could conceivably now be improved in
>some ways in that it may be \"softer\", or springier, or match the
>spring constant of a horse\'s leg better than expected, and have
>fewer inconsistencies in depth and composition and drainage ( future
>drop hammer tests and ground penetrating radar studies from the
>Jockey Club\'s track safety initiative will help determine these
>things).
\"TUNED\"TRACKS FOR THE SPRING CONSTANT OF THE SURFACE CAN BE FASTER and SAFER FOPR HUMANS, BUT TO DO THAT YOU NEED A TON OF DATA ON THE LOCOMOTION VARIABLES, AND OUR COMPANY IS THE ONLY ONE TO HAVE THOSE DATA BASES, AND NO ONE ASKED US.
Furthermore, good athletes there may compensate in the
>velocity of their foreleg retraction somewhat,
>
>but, -- still, -- more potential force in mega units, is still just that.
>
>
>
>Physics says force increases as an exponential (actually the square)
>of velocity [ i.e., f = mass*(velocity squared) ].
>
>The faster times we\'re seeing at Santa Anita now, mean more
>multiples of the force (see physics summary below).
>
>Could this possibly mean it will lead to more injuries?
>
>The new 7 furlong record the other day at Santa Anita was 1:19 and change.
>
>According to the Thoroughbred Times Racing Almanac (master racing
>journalist Don Clippinger\'s creation), Spectacular Bid\'s record was
>1:20, and the fastest time in 2007 on the new synthetic was 1:20.37.
>The fastest 7f time on the old dirt track that year was 1:21.11 by
>Latent Heat.
>
> The average force already on a Thoroughbred racehorse leg at 12
> secs per furlong (55 ft per sec) is roughly describable by force
> = mass (1,000 lbs) times velocity (55 ft/sec) squared. (see Nat\'l
> Science Foundation racetrack force plate studies by Kingsbury in the Journal of Biomechanics]
>.
>[note -- the foreleg retracts - goes backwards, before hitting the
>ground so the leg velocity is less at impact than the main inertial
>mass velocity. On the other hand, the faster they go, the more
>extended they are, and the less foreleg retraction before impact.
>The rear legs really don\'t have that sort of retraction.]
>
> Changing from about 1:22 for seven furlongs to 1:19 is a change
> of 3 seconds overall, or probably at least 1 sec per furlong of
> velocity somewhere in the race.
>
>Go 1 second per furlong faster and the overall velocity is about 5
>ft/sec faster. So, for example, if you go 1 sec per furlong faster,
>instead of a velocity of 55 ft/sec, you\'d have 60 ft per second. Put
>that into the force equation above. 55 squared is 3,025 times the
>mass = force. 60 squared is 3,600 times the mass = force.
>That is 575 times more units of force possible.
>
>Yes, Santa Anita\'s new track could conceivably now be improved in
>some ways in that it may be \"softer\", or springier, or match the
>spring constant of a horse\'s leg better than expected, and have
>fewer inconsistencies in depth and composition and drainage ( future
>drop hammer tests and ground penetrating radar studies from the
>Jockey Club\'s track safety initiative will help determine these
>things).
\"TUNED\"TRACKS FOR THE SPRING CONSTANT OF THE SURFACE CAN BE FASTER and SAFER FOPR HUMANS, BUT TO DO THAT YOU NEED A TON OF DATA ON THE LOCOMOTION VARIABLES, AND OUR COMPANY IS THE ONLY ONE TO HAVE THOSE DATA BASES, AND NO ONE ASKED US.
Furthermore, good athletes there may compensate in the
>velocity of their foreleg retraction somewhat,
>
>but, -- still, -- more potential force in mega units, is still just that.
>