Jan-Anders Manson, Ecole Polytechnic Federale De Lausanne, Switzerland
Meera - Now, to finish off, we take a look at how science and technology may sometimes take its role in sport a little too far. So far, that it is then banned for giving athletes too much of an advantage. This was and is the case for polyurethane swimsuits which, as of the 1st of January 2010, were officially banned from use in official competitions. Jan-Anders Manson, Head of the Polymers and Composites Laboratory at the Ecole Polytechnic Federale De Lausanne in Switzerland explains whyÖ
Jan-Anders - We kind of differ between two different type of sports: Sports where you have equipment and sports where you donít have equipment. Swimming is considered as a sport where you donít have equipment, you have just dress [clothing] and that should not be a major part of the performance of the athletes. In 2008, we start to see a type of suit coming that was a polyurethane suit. There were very high forces in the suit so they could compress the body to a shape that was higher performance. It was also non-permeable, so, if you had air inside the suit, it would have difficulty coming out which could also influence the buoyancy effect. What you always want to have from a swimmer is to have a dolphin-like shape of the body and of course, when you have high compression, you can shape your body in an optimal way.
Meera - Are these the traits that these new suits were introducing, affecting the swimmerís bodies in this way?
Jan-Anders - Primarily it influenced the shape of the body and also the surface of the suits and the third one is also that air could be trapped between the body and the swimsuit.
Meera - What is the material that was enabling these suits to perform in this way and make these changes? You mentioned it was polyurethane, but how does this enable such properties?
Jan-Anders - This material is a totally tight rubber-coated textile, there was rubber material covering the whole swimsuit. Air cannot pass through it.
Meera - The other difference was that the suit had a lot more material to it, so it actually covered more of the body to allow these changes.
Jan-Anders - Yes, exactly. The men and the women had the same type of suit that covered from knee to shoulder in both cases. In the new rules, for men, itís knee to navel and for women, itís knee to shoulder like before.
Meera - What kind of changes are these making to performance? So they're affecting the swimmerís drag in the water and also their buoyancy which must make quite a difference to their swimming performance.
Jan-Anders - Yes, so those are the 3 effects. It was the drag, the floating position, and also the shape of the body.
Meera - Were there any figures as to how much of a difference this could make? So say, in the championships where they were used, how much difference did we see?
Jan-Anders - Itís difficult to say in time, for instance depending on distance, but we saw a higher effect on shorter distances, so 50 and 100 meter, and less on long distance like 800 and 1500 meter. Following the record of evolution in many sports that have no equipment involved, we talk about a 1% improvement over 4 years, in record evolution with elite athletes. Swimming was laying around 0.8-1% over the last 50 years of performance increase. But during the last 2 years, 2008-2009, we started to see it was up to 1% over 1 year. A considerable performance increase when these suits were introduced.
Meera - Why did these suits make a bigger difference in to shorter distances? Surely, even for longer distance swims, being able to move faster is still important?
Jan-Anders - The suit helped the core muscles of the athletes. It could replace some of the stomach muscle to help them to keep horizontal position in the water. When you get tired and the stomach muscles get tired, you sink down with your bottom part of the body which increases the drag. The second issue is if you have air trapped under the suit, it will diffuse out for a time, but in the beginning of the race, it had more of an influence.
Meera - So when they're not actually in the water for longer, it has a greater impact.
Jan-Anders - Exactly.
Meera - Why was this suit the cut-off? Weíve seen changes in swimsuits used by professional athletes over many years, shark skin-based suits were incorporated and various other technologies have been used. Why was the line drawn here, the polyurethane?
Jan-Anders - For the reason, it was absolutely tight and it was very, very high forces that could be introduced in the suit. It could really compress the body to even out all difference in the body shape and the air couldnít come out. It was under the suit.
Meera - What's the situation now then? What kind of suit is allowed? And what limit of technology is acceptable now?
Jan-Anders - The suits have to be made of a textile material. Textile material, it means when you stretch it, it open up holes in there so the air can come out. There is no plastic allowed to be put on top of the textile. They have to be thinner in thickness and that also limits some of the compression forces that you could put on the body.
Meera - Is there an actual thickness thatís been set?
Jan-Anders - Yes. The thickness is 0.8 millimetre and the permeability of the textile has to be more than 80 litre per square metre so that how much air can get through the textile, and then there's a buoyancy requirement on the textile material as well. It can't be too light and this is done also in close discussion with the manufacturer. We have to meet with them regularly as well as with the athletes and the coaches.
Meera - This year, the London 2012 Olympics will be the first Olympics then since this ban has been incorporated and introduced. What difference do you expect to see to the swimmers and their performance this year?
Jan-Anders - I donít expect to see as many world records as we have maybe been used to. Just to give you an example in Rome, I think we had 26 world records, that was 2009, and the world championship in 2011 in Shanghai, we had one on the 1500-meter. So yes, it will hold back the times slightly, but this is just a matter of time until the athletes capability has regained that difference. So, I expect to see some world records but not the same amount maybe as we have seen in the previous Olympics.