Elite swimming and the bodysuit question

Guest blogger
Sports engineering

Steve Haake is professor of sports engineering and the head of the Centre for Sports Engineering Research at Sheffield Hallam University. In 1998, he became the founding editor of the Sports Engineering Journal and the founding chairman of the International Sports Engineering Association, holding both positions until 2004. He is a technical consultant to the International Tennis Federation.

Question 1.  Does technology in sport work?

As a technologist working in sport, I often get asked about the issue of fairness, as do those who administer the game.  Quite often it is difficult to tell the effect of a particular technology as it is usually introduced over time.  Certainly, a clearer way is to see what happens when something is banned as the change happens suddenly. 

swim
Polyurethane suits undoubtedly helped swimmers break records, but were they fair?

Take the example of the recent furore over swimsuit technology.  If you can’t quite remember, then this is what happened.  Polyurethane panels were introduced to swimsuits around 2000 with suits gradually changing in size and shape to become full body urethane suits by around 2008.  It should be added that these suits were sanctioned by the ruling body of swimming FINA. 

However, in the FINA World Championships in Rome in 2009, 42 world records were set and there was uproar in the media.  FINA changed its mind on the swimsuits and full body polyurethane swimsuits were banned from 1st January 2010.  The data in the figure below shows how the ban affected the men’s freestyle event.

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Figure title: Average of the top 25 speeds in the men’s freestyle.

So, to answer the first question – does technology work?  Well, the figure clearly shows that swimming speed increased significantly at Beijing in 2008 and Rome in 2009 (although you will also notice that speeds tend to increase slightly in an Olympic year anyway).  The anecdotal evidence appears to point towards the fact that the full body swimsuits have two effects: (1) they reduce the cross sectional area of the swimmer by ‘tucking’ things in ; (2) they reduce the skin friction of the body as it passes through the water.  Both these effects reduce drag which then allows the swimmers to go a fraction faster.  Interestingly, the increase seems stronger in the shorter events with a minimal effect in the 1,500 m where speeds are about 75% of sprint speeds.  It is possible that either the skin friction effect is non-linear with speed, or that the stiffness of the swimsuits fatigues the swimmer more, particularly in the longer events were there are more tumble turns (29 in the 1,500 m compared to none in the 50 m). 

    50m 100m 200m 400m 800m 1500m

Difference (s)

2009-2011

Men 0.61 0.58 2.44 1.41 6.45 -0.42
  Women 0.41 1.38 2.08 2.82 3.41 7.05
Estimated years to new world record? Men 10-14 1-8 8-9 4-10 5-17 0
  Women 3-8 4-12 1-8 1-5 2 1-3

Table 1.  Margins between 2009 and 2011 times for men’s and women’s freestyle, and approximate times to for the margin to be made up.

Question 3. What happens if you ban it?

So, the technology seems to work and Table 1 shows the approximate increases in time produced by the ban in 2010.  However, one thing that FINA may have missed is that they now have world records in 2009 that will take quite some time to beat (Table 1 indicates 1-2 decades in some circumstances. 

Question 2. Is technology fair?

You may have noticed that I missed out question 2, probably the trickier of the questions to answer.  If the suits are only available to one or two, then of course there is a clear advantage and one could argue that the sport was compromised.  However, the suits were initially sanctioned by FINA and the evidence was that most swimmers were using them; after all the data in Figure 1 is for the top 25 athletes which shows that the average effect was that they all increased in speed.  What tends to happen with interventions in sport is that most elite athletes take up technology very quickly so that individual advantages do not last very long. 

Going back to FINA, what are their options with swimsuits now that world records have been compromised?  Well, they could opt for the status quo and see how things go.  They could lift the ban and let all swimsuits be used again with the confusion that this might create.  A third way might be to set a ‘new rules world record’ from 1st January 2010 reflecting the fact that records pre- and post-2010 are judged differently.  Whatever happens, not many records will be broken in swimming at London 2012.