Below the PDF of the conference of Canova pre-Campaccio, italian cross country race.
Canova uses % in percentage on the race rhythm and not as it is done in physics and in the USA, that is in m / s.
As Canova does, you have the same symmetry above and below the race pace, for example 90% and 110% equidistant in seconds from the race pace, while how do you do in the USA and how do you physics in m / s you do not have the same symmetry above and below the race rhythm:
For example, race pace of 180 seconds, in the USA would do so:
180 x 100/90 = 200"
180 x 100/110 = 163"64
And the differences are not symmetrical:
200-180 = 20"
180-163 "64 = 16"36.
While as Canova does:
180/100 = 1,8 seconds.
1.8 x 10 = 18.
from which:
90% = 180 + 18 = 198 "
110% = 180-18 = 162 "
And they are equidistant from the race rhythm.