A listener to the BBC radio programme “More or Less”, which delves into statistical issues behind topical news items, asked why so many swimming records were broken during the Olympic Games, compared to the relatively few athletics records which fell. After all, we would expect that, with greater understanding of how the body works leading to better training and improved nutrition, a steady stream of records should be broken across all sports. However, looking back to the London Olympics, the only track records which were broken were the 800m and the 4 x 100m; in the pool, nine records were broken. And, since 2000, 6% of track records have been broken against 40% of swimming records.
Any idea why they should be so different? It turns out that there are a number of reasons.
Firstly, whereas there is not much you can do to change how you run, swimming strokes are immensely complex, leaving lots of room for optimisation. Adam Peaty comprehensively smashed the 100m breast stroke record, and this was partly due to his trainer devising an entirely new way, within the rules, of the movements within the stroke. This enabled Peaty to increase his stroke rate from 50 per minute to 58 per minute. However, this power stroke needs so much energy that it couldn’t be sustained over longer distances such as 200m.
Secondly, the conditions under which races take place have a huge effect on record-breaking potential. Track events are run in the open air, and factors such as temperature, altitude, humidity and wind speed all affect race times: records will only be broken when the conditions are perfect (not very often), even though athletes are improving all the time. However, every pool is exactly the same in terms of depth, temperature, water content – and they are usually indoors. This means that every improvement in a swimmer’s style, fitness and so on, is going to lead to faster times. Rule changes have also meant faster turns.
Thirdly, there have been improvements in swimming technology which have been very significant. For example, the introduction of goggles in the 1970s meant that swimmers could train for much longer before damaging their eyes: typically from 10 hours per week up to 25 hours per week. Another innovation is body suits which reduce drag.
Finally there is the issue of doping. It is likely that many of the track and field records of the 1980s were broken under the influence of illegal doping, and it is hard even now to break those records. However, the improvements in swimming listed above have meant that swimmers have been able to break the “illegal” records: most swimming records are now “clean.”
Statistics can tell a story, but often there is much more behind the statistics than the raw numbers themselves reveal.
Picture credits: Olympic.org, the Times, NBC Olympics, Coachrick Swimming