My name is Dr Ross Tucker, I am an exercise physiologist based in the
Let me state first and foremost my position - I do not think that Pistorius should be allowed to compete against the able-bodied runners until it is conclusively shown that the limbs do not assist performance. It is likely we agree on the fact that research is required in order to establish whether his prosthetics are in fact an advantage or disadvantage. We are all aware of the hype and comment on this topic. However, the current angle you have taken is risky and the IAAF is in danger of putting itself in a compromised position if it accepts the responsibility to perform the research during his competitions at future IAAF meetings.
It is my understanding that your plan is to allow him to run and then to monitor stride length and frequency during his 400 m races. However, by doing this you are destined to show only that he does not have an advantage, and this would be a Type II statistical error because you are asking the wrong question.My involvement with Oscar Pistorius is of direct personal origin. As I have mentioned I am an exercise scientist and an athletic coach. I recently coached another South African athlete who won medals at the Paralympic Games of Athens 2004. Based on this, I was contacted in October 2004 by journalists seeking my opinion on whether Pistorius’ prosthetics were an advantage or disadvantage. My responses were the following:
- Firstly, the legs must be considered to provide an advantage until such time that it was proven otherwise by Oscar Pistorius. The burden should be entirely on him to show that he gains no advantage running on feet specially designed for speed
- Secondly, because of his inability to balance out of the starting blocks, his current events of the 100 m and 200 m would not be his strongest. I said in 2004 that he would be able to challenge able-bodied athletes if and when he went up to the 400 m distance. This has now happened, and it has been borne out.
Now, my reasons for writing this in 2004 were the following:
- Based on an analysis of Pistorius' races during the 2004 Olympic Games, it was obvious to me that he was at a severe disadvantage at the start of the race because by the time the other athletes had run 30 m, Pistorius had done 20 m. Yet he was always able to catch and then pass his opposition to win by 5 m or more. There was even a race where he stumbled, stood up and then managed to catch up to the other runners and win the race.
My conclusion then was that his ability to catch up and make up the distance that he lost over the first 30 m was unnatural, suggesting that he had some advantage as a result of his limbs. In effect, he was running 80 m while others where running only 65 m, at least a full second and a half difference. The opposition athletes were single leg amputees and this gave them better ability to balance and thus they were able to start faster, but unable to reach the same top speeds as Pistorius. To me, this was the first evidence that we were witnessing a performance-enhancing effect of the limbs.
- Anecdotally, his stride length and incredibly high stride rate were the factors that were responsible for this difference.
These two factors led me to suggest in 2004 that the IAAF would soon be faced with a very difficult predicament, because it was inevitable that Pistorius would soon step up to the 400 m event. Here, his slow start would not be as much of a barrier to success and he would be a candidate to run an Olympic able-bodied qualifying time for the 400 m event.
My colleagues at the Sports Science Institute of South Africa shared this view. Professor Tim Noakes was also contacted and echoed the sentiments I expressed above, though we did not confer at any time. I have no doubt that you have heard similar concerns regarding the limbs.
My next interaction with Oscar Pistorius was when his agent contacted me in early 2006 to say that he would bid to run in the Olympic Games in
In addition, for technical reasons that I will not go into here, there are factors that must be explained, because from a pure physics point of view, Pistorius does in fact have certain advantages. It is important to note that these advantages may in fact be present without the expected increase in stride length. For example, the metabolic cost of accelerating a carbon-fibre limb may reduce the work of running for Pistorius by more than he loses by not having certain muscles to perform that work. This would not require an increase in stride length to enhance his performance.
Recently I communicated with Pistorius and his group and they proposed that research be done on the prosthetics. However, this communication stopped and has never been re-initiated since. At about the same time, Pistorius’ agent contacted Professor Tim Noakes, who also said that research was required before it could be conclusively stated that the legs did not confer an advantage. In neither case was research done.
Currently we have a situation where it is the IAAF who has been tasked with the responsibility of doing the research to either prove or disprove this theory about Pistorius’ prosthetics. Let me again emphasize that I firmly believe it is not the responsibility of the IAAF to prove this due to a very obvious conflict of interest. However, research is clearly required, and it is critical that the research be performed professionally so that we do not incorrectly find that the prosthetics either do or do not provide an advantage.
The media have reported that you are going to allow Pistorius to run in the 400 m races at future IAAF meetings and use video technology to analyse his stride patterns. This will fail to find any effect, even it exists, because the 400 m event is sub-maximal by nature and thus his stride length will be constrained in accordance with the pace he chooses to run at. The benefit of the limbs, if any, is therefore an energy conserving one. Since you will not be in a position to measure the metabolic demands of his running, so you will never know whether or not the limbs work. Therefore, there it is likely that you will experience a Type II error (a false negative), because you are analysing the wrong circumstances.
The only way you will be able to discover whether the limbs provide him an advantage is by the following:
- Analyse a 100 m race, and examine only the final 50 m. If Pistorius’ stride length or frequency is higher during this phase, this is an indication that his limbs are transferring energy that enhances his stride mechanics.
- However, as I pointed out, there are factors that might contribute to improved performance without necessarily increasing his stride length. Just because his stride may be the same length, does not mean he does not have an advantage.
- Therefore, we must attempt to analyse the elastic recoil of the limbs. For this, you would require an extremely high-definition camera which can film the flex and potential storage of energy in the limb between the time where Pistorius’ prosthesis makes contact with the ground and toe-off. If the limb flexes and then ‘releases’ this energy, then the limbs should be disallowed, for they are clearly providing an elastic recoil that an able-bodied runner does not possess.
- On this note, one might wonder why the limbs have this very specific bend and shape. The reason is comfort but also the advantage it gives to elastic energy. In fact, a member of Pistorius’ family has stated that in the beginning, Pistorius wore “primitive prosthetics” and they (the manufacturers) have since changed the shape. If this is not an indication of the role of design in speed, nothing is.
Further to this, there are a number of studies which can be conducted to investigate this debate, although I will not discuss these here. If the IAAF continues on its current path, there is real danger of creating an untenable situation. I recognize that this may be an unpopular decision since it may be seen as discriminatory to prevent a Paralympic athlete from competing in the Olympic Games. However, I repeat, the burden to prove that the limbs do not improve performance lies with Pistorius, not the IAAF. However, all parties have too much to lose and this is the reason why, despite my and others’ suggestion, no scientific research has yet been performed.
Finally, let me say that I believe that Oscar Pistorius is a great role model for everyone, not only those with amputations. I think that his courage and spirit are fantastic, and my scientific stance in no way reflects on my perceptions of his efforts as an athlete or a human. However, in the name of the sport, which surely is greater than any individual, I urge the IAAF to strongly consider its approach to this research before we make a great mistake, one way or the other.
Dr Ross Tucker
Tel: +27 21 6504577
Fax: +27 21 6867530
UCT/MRC Research Unit for Exercise Science and Sports Medicine