Re: Pistorius - a considerable advantage?

[Guest guest]

>

> Here's a press release from the International Paralympic Committee

(IPC) regarding the

> recent report from the IAAF:

>

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The below was recently published on the IAAF website:

Pistorius - Independent Scientific study concludes that cheetah

prosthetics offer clear mechanical advantages

Monday 14 January 2008

Monte Carlo - The IAAF has received the results of an independent

scientific study carried out by Professor Brüggemann at the

German Sport University in Cologne. This study made a biomechanical

and physiological analysis of long sprint running by a double

transtibial amputee athlete Pistorius (RSA) using " cheetah "

prosthetics, and also compared this athlete with five able-bodied

athletes who are capable of similar levels of performance at 400m.

The tests, which took place on Monday 12 and Tuesday 13 November in

the Institute of Biomechanics and Orthopaedics, were initiated by the

IAAF with the approval and participation of in order to see

whether the prosthetics used by him should be considered as technical

aids which give him an advantage over other athletes not using them,

in contravention of IAAF competition rule 144.2.*

The objective results of this study are that:

- Pistorius was able to run with his prosthetic blades at the same

speed as the able-bodied sprinters with about 25% less energy

expenditure. As soon as a given speed is reached, running with the

prosthetics needs less additional energy than running with natural

limbs.

- Once the physiological potential of Pistorius and the able-

bodied control athletes had been estimated, using three different

methods, it is clear that Pistorius' potential was not higher than

that of the controls, even though their performance results were

similar.

- The biomechanical analysis demonstrated major differences in the

sprint mechanics used by a below-knee amputee using prosthetics when

compared to athletes with natural legs. The maximum vertical ground

reaction forces and the vertical impulses are different in a highly

significant way and the amount of energy return of the prosthetic

blade have never been reported for a human muscle driven ankle joint

in sprint running.

- The positive work, or returned energy, from the prosthetic blade is

close to three times higher than with the human ankle joint in

maximum sprinting.

- The energy loss in the prosthetic blade was measured at 9.3% during

the stance phase while the average energy loss in the ankle joint of

the able bodied control athletes was measured at 41.4%. This means

that the mechanical advantage of the blade in relation to the healthy

ankle joint of an able bodied athlete is higher than 30%.

It is evident that an athlete using the Cheetah prosthetic is able to

run at the same speed as able bodied athletes with lower energy

consumption. Running with prosthetic blades leads to less vertical

motion combined with less mechanical work for lifting the body. As

well as this, the energy loss in the blade is significantly lower

than in the human ankle joints in sprinting at maximum speed. An

athlete using this prosthetic blade has a demonstrable mechanical

advantage (more than 30%) when compared to someone not using the

blade.

IAAF Council has been able to review the full report and has decided

that the prosthetic blades known as " cheetahs " should be considered

as technical aids in clear contravention of IAAF Rule 144.2. As a

result, Pistorius is not eligible to compete in competitions

organised under IAAF Rules.

Note for editors concerning test procedures and parameters:

- Analysis was carried out by a team of more than 10 scientists,

including staff from the physiology laboratory of Professor J. Mester

(Institute of Training Science and Sport Informatics).

- 12 high speed cameras (250 frames per second) were used to record

3D kinematics, with another 4 highspeed cameras to observe sagittal

plane motion

- Force platforms were used to record ground reaction forces and

point of force application

- Athletes ran the 400m test with a K4 mask to record max VO2. VO2

testing was also carried out in the laboratory (Wingate and Ramp

Test) on static bicycles. Blood lactate records were taken regularly

- A 3D scanner was used to record body mass and anthropometric

measures of all the control athletes

- The prosthetics were also subjected to material testing

* IAAF Rule 144.2 extract

Relates to the use of " technical aids " during competition

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Carruthers

Wakefield, UK