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Re: Fw: Dinosaurs and birds



Science is indeed wonderful, but I note in passing
1) that these were highly trained athletes
2) that they used an elastic towing device to even out pulses (birds would have a pulsed thrust and lift).
3) they were not subjected to pulsed lifting forces while being uniformly towed.
4) if the 6.8% increase in running speed held between species (which I doubt), then it would lead to a 14% increase in lift and a cocurrent decrease in thrust.
5) wind gusts are typically on the very loose order of 25% of wind speed (subject to considerable variation). This would lead to a transient 56% increase in lift with no consideration for flapping. Being naturally lazy, I'd probably wait around for a gust and do it the easy way.
6) cursorial birds aren't observed to use wing-assisted straightline sprinting.
JimC



----- Original Message ----- From: "don ohmes" <d_ohmes@yahoo.com>
To: <dinosaur@usc.edu>
Sent: Monday, April 16, 2007 11:06 AM
Subject: Re: Fw: Dinosaurs and birds



KINEMATICS
OF ASSISTED AND RESISTED SPRINTING AS COMPARED TO NORMAL FREE SPRINTING IN TRAINED ATHLETES


“The mean values for average running speed, stride rate, stride length and support time
are presented in Table 1. The AS condition resulted in an average increase of 6.8%
in average running speed as compared to the FS condition.”


Ain't science wonderful?