Well, I used to fly CRJ200s, and it has a very soft and compliant trailing link gear.  Every now and then, I happened to get the pitch teasing through the touchdown just right, and the ground contact was so gentle that the only sensation of a landing was the wheel spin vibrations/noise starting.

When that happened, there was no discernable deceleration at wheel contact from the spinup. So while there is probably a measurable effect if you had accelerometer data measuring longitudinal G at  main wheel contact, it's not enough to feel through your butt and therefore not really significant in terms of landing distance. You get more detectable deceleration from spoilers and full flaps, and when you get on the brakes, well, you know it.