Nowadays they compensate for the fact that athletics records are being broken more narrowly by measuring them more accurately, as this historical chart shows: 2000 B.C. Ancient man runs 100 ox hides in about half a pint by the local water clock. 1500 A.D. Renaissance man shaves a bit off this and runs 100 paces in 10 ticks of the pendulum. 1950 A.D. Roger Staircase improves this to 100 yards in 10 seconds (to the nearest second). 1980 A.D. Billy Whizz does 100 metres in 9.9 seconds. 2050 A.D. Hugh Manoid does 100.0000000 metres in 9.2567823409878 seconds.
(From the "Rest" of RHF)