Originally Posted by Bob Sacamano
again, this formula is measuring quickness
I think you're having trouble reading. Look at this:
Originally Posted by Kirwan
Then I looked for athletes with average-to-below average 40-yard times for their position who make up for the lack of long straight speed with exceptional quickness and change of direction.
Kirwan is looking at the shuttle time
to see if a player that doesn't have "long straight speed" (which is measured by the 40 time) can make up for that deficiency by having exceptional quickness (which is measured by the shuttle time). Kirwan's entire point is that "quickness" is measured by the shuttle time, rather than the 40.
The difference between 40 time and shuttle time doesn't measure quickness. The shuttle time measures quickness. The differential just measures their quickness relative to their 40 time