The fastest sprinter in 2068 has an artificial limb?

Dear Editor,

Recent developments in carbon fiber running-specific prostheses (RSPs) with energy-storing capabilities have allowed individuals with lower extremity amputation (ILEAs) to regain the ability to run. This phenomenon exemplifies how ILEA sprinters are highly motivated and work hard as well as how current prostheses have advanced. This raises the following question: How fast would RSPs allow ILEA sprinters to run? Although several studies predicted limitations in sprint performance in able-bodied sprinters (ABSs),^1,2 no studies have been reported for ILEA sprinters. We assessed the progression of the winning times of the men’s 100-m sprint in the Paralympics and compared them with those in the Olympics.

The winning times of the men’s 100-m sprint in the Olympics were obtained from the official website of the Olympic Movement (http://www.olympic.org/). Data were available every 4 years from 1900 to 2012 except for 1912–1920 and 1936–1948 when the Olympic Games were cancelled due to World Wars I and II, respectively. We also acquired data for the winning times at the Paralympics from the official website of the Paralympic Movement (http://www.paralympic.org/). Data were available every 4 years from 1976 to 2012. In this study, we included the winning times of the men’s 100-m sprint in the C (1976 and 1980), A4 (1984), A4-A9 (1988), TS2 (1992), T43-44 (1996), and T44 (2000, 2004, 2008, and 2012) classifications.

We performed regression analyses to predict the winning time for future Olympics and Paralympics for ABS and ILEA sprinters, respectively. Since the carbon fiber prosthesis was first seen in elite sporting events at the 1988 Paralympic Games, ³ data for ILEA sprinters in 1976, 1980, and 1984 were excluded from the regression analyses. The 95% confidence intervals on the predicted winning times were also calculated in the analyses. The significance was set at p < 0.01 in each regression analysis.

The difference in winning times between ABSs and ILEAs was over 4 s in 1976 (Figure 1). The ILEAs shaved approximately 1.5 s off the time difference from 1984 to 1988. This improvement may be attributed to the advent of carbon fiber prosthetic feet at the 1988 Paralympic Games. ³ These results suggest that technological interventions, such as the advent of RSPs, would contribute to the improvement of the sprint performance of ILEAs. In other words, revolutionary new materials or technical advances may induce drastic performance improvements in the future, similar to that seen from 1984 to 1988.

Figure 1.

Men’s 100-m winning times for ABSs (unfilled circles) and ILEAs (filled circles) superimposed with best-fit linear regression lines (solid lines) and regression coefficients of determination. An asterisk indicates a significance of p < 0.01. The dotted lines indicate 95% confidence intervals for each regression line. Since the winning times in 1976, 1980, and 1984 for ILEAs were achieved by non-RSPs, ³ we excluded that data from the regression analyses. The current world records as of 29 September 2014 for the men’s 100-m sprint in ABSs (9.58 s by Usain Bolt) and ILEAs (10.57 s by Alan F. Oliveira) are also represented by unfilled and filled squares, respectively. The world record data were excluded from the regression analyses.

As of 2012, the difference between the two groups has gone down to 1.27 s. The current world records (as of 29 September 2014) are 9.58 s for ABS and 10.57 s for ILEAs, which represent a difference that is already less than 1 s. Our regression model predicted that ILEA sprinters would outperform ABS in 2068, where the predicted winning times could be 9.039 and 9.046 s, respectively. These results indicate that if current trends continue, the fastest sprinters in the world may be ILEAs from 2068 onward.