Forty-three world record swims were recorded at the 2009 Fédération Internationale de Natation (FINA) World Championship meet in Rome. Of the 20 FINA recognized long-course (50-m pool) swimming events, men set new world records in 15 of those events, whereas women did the same in 17 events. Each of the men's world records and 14 of the 17 women's records still stand (6). These performances were unprecedented; never before had these many world records been broken in such a short period of time. There was much speculation that full-body, polyurethane, technical swimsuits were the reason for the conspicuous improvement in world records. Further analysis led the FINA to institute new rules on January 1, 2010, that limited the types of technical swimsuits that could be worn by athletes. No long-course world record has been broken since then (Figure 1). We sought to understand why.
Although many people suspected that these technical suits were performance enhancing, there was some genuine uncertainty as to the extent of that effect. Now, with a full year and a half of data since the new regulations have been instituted, we are able to assess with some certainty the extent to which these suits were responsible for the outstanding performances of 2009 (Figure 2).
We first investigated the unique nature of the 2009 performances by looking at publicly available race data (5,6) to see if similar sports experienced similarly dramatic performance improvements. Track provides an effective juxtaposition to swimming because both sports involve athletes competing in individual or medley events of a similar duration. These similarities allowed us to meaningfully compare historical data between these sports and control for energy systems (sprint vs. endurance events), performance psychology, training methods, and relative popularity of the sport. Additionally, track is free of similar equipment controversies, so it allowed us to begin to isolate the equipment variable.
Historically, world records in swimming have been broken far more frequently than those in track. Since 1900, the world record in the men's 400-m dash (a track event) has been broken 21 times; for a swimming event of a comparable duration, the men's 100-m freestyle, the world record has been broken 48 times (5,6). Perhaps this frequency difference can be attributed to standardization and changes in swimming regulations (depth of pool, types of lane lines used, height and angle of starting blocks, water temperature, etc.); improved swimming technique; improved training science; increased access to the sport; and improved swimwear. Certainly, track has experienced similar changes that have collectively improved the performances of athletes, but it has not seen the same degree of performance improvement that swimming has seen over the last century. Could a continuing evolution of these components explain the outstanding swimming performances of 2009?
If training science had improved significantly, that could help to explain the phenomenon. However, since 1990, there have been no major changes in the regulations for either sport (2,4), yet sprint (anaerobic) swimming performances have continued to improve at a much more dramatic rate than have sprint track performances. From 1990 to 2010, men ran 2.85% faster in the 400-m dash and swam 5.86% faster in the 100-m freestyle. This improvement was not gender specific: Women ran 3.29% faster in the 400-m dash and swam 5.57% faster in the 100-m freestyle (5,6). If progress in training science were the explanation, we would have expected to see similar rates of improvement in both sports because progressive developments in training science are quickly disseminated and adopted across athletics. Instead, we note a significant difference between sports in the rates of improvement with swimming demonstrating far greater improvement.
We note similar trends with endurance (aerobic) events. Men ran 3.59% faster in the 3,000-m run and swam 5.76% faster in the 800-m freestyle. These percentages are highly consistent with those of the sprint events, so the different physiological demands of these 2 event types cannot explain the phenomenon either.
Increased access to the sport of swimming could help to explain the phenomenon. If more people entered the sport and increased the competitive base of the sport, we might expect to see improved performances as a result. Looking at the membership trends for U.S. Swimming from 1990 to 2010, we found that membership has risen at an average rate of 3% per year with consistent and predictable spikes of 4–11% in post-Olympic years (7). These steady increases in membership would be expected to correlate with the steady improvement in swim performances. However, this is not the case. Swim performances have improved at rates greater than those of membership.
Another consideration is the presence of some unique talent that could account for the performances leading up to and including the 2009 FINA World Championship meet. Michael Phelps accounted for 3 of the 15 world records at the 2009 FINA World Championship meet. With the exception of Phelps, no other single athlete at the 2009 FINA World Championship meet broke >2 world records. Many athletes broke many world records, and no one talent was responsible for a bulk of the performances.
Having excluded these other possibilities, we were left to consider technical swimsuits as the major reason for the improved performances. Full-body, technical suits were worn by all of the athletes who broke world records at the FINA championship meet. These technical suits were able to reduce drag, improve buoyancy, and enhance body compression (3)—all of which could separately or jointly account for improved performance. One anecdotal piece of evidence for this hypothesis came from Michael Phelps' coach, Bob Bowman, who commented after Phelps' surprising loss in the 200-m freestyle to Paul Biederman: “It took me five years to get Michael from 1:46 to 1:42 and this guy has done it in 11 months. That's an amazing training performance. I'd like to know how to do that,” (1) suggesting that the suit was the cause of the conspicuous performance improvement.
Since January 1, 2010, the FINA has changed the requirements for technical swimsuits. The new rules prohibit the use of the swimsuits that were worn to set all currently standing world records. Since this change was implemented, no long-course world record has been broken.
So what explains the unprecedented run of broken records? It would be unfair to discredit the dedication and training of these athletes and their coaches. This has certainly played a role. We conclude that the upward trend in times (slower times) since the end of 2009 is likely to be significantly linked to the new regulation of technical swimsuits. The data indicate that it was more than just hard work that allowed these athletes to break an unprecedented number of world records in a record period of time: The equipment played a significant role, too.
The implications of this for the athletic community are far reaching. As a community, we continue to make a strong effort to protect our respective sports from the effects of artificial enhancement. Swimming has provided us with a vignette in which technical equipment has created an iterative (Figure 1) artificial enhancement. Although much focus is given to doping, it is important to be aware of other sources of artificial enhancement as well.
1. Associated Press. Coach threatens to pull Phelps. Available at: sports.espn.go.com. ESPN.com, 2009. Accessed on June 12, 2011.
2. FINA. FINA swimming rules 2009–2013. Lausanne, Switzerland: FINA, 2009.
3. FINA. Report from the FINA Dubai, UAE: Swimwear Approval Commission. 2010. pp. 1–12.
4. IAAF. IAAF competition rules. Monaco: IAAF, 2010.
5. IAAF. IAAF top lists database. Available at: iaaf.org. Monaco: IAAF, 2011.
6. SwimNews. Best performances database. Available at: swimnews.com. 2011. Accessed June 10, 2011.
7. USA Swimming. USA Swimming 2010 Membership Demographics
. Fort Collins, CO, 2011. pp. 1–36.