I was training for the Atomiade, an amateur sport event among people working in science institutes. For fun, I was comparing the performance times of the team with world records. This is how I found that not only my times were depressing, but also that the speed reached in professional competitions, for different races, as a function of the race time, can be described by two scales laws, well defined and similar for me and women, for runners and swimmers.
This result was published in collaboration with Vincenzo Carbone (University of Calabria) and in Nature in 2000. Vincenzo and I continued on investigating more interesting effects, including forecasting in athletic world records.
More interesting results can be seen in this presentation.