According to the supplementary information at Nature's website, the data span the years from 1928 to 2004 (76 years) for women, and from 1900 to 2004 (104 years) for men. After testing a range of curve-fitting procedures, the scientists adopted the simple linear relationships between the Olympic year and the winning time. The extrapolation to the year 2156 goes ahead for 152 years, just two times of the time span in which the data for women exist.
From my much experience of curve fitting to data , I suppose that the validity of such wild extrapolation is quite dubious. It is just a child's guesswork. Reliable extrapolation would be up to the year of about 2042 (2004 plus a half of 76). -- Can I live until that year? -- If the linear decrease of the winning time goes on and on, there would come the year when one can reach the goal in no time (this is a child's words).
- A. J. Tatem, C. A. Guerra, P. M. Atkinson and S. I. Hay, Nature Vol. 431, p. 525 (2004).
- See the list of my academic papers.