[Thor]

Iceman is right, you will see much more difference when gaining a rank with those who you have a hard time fighting usually. If you used to beat an inactive target in 10 rounds, you wont see any difference with 1 skill level but the guy who used to always beat you in 59 rounds and have 50-100 hp left might have a few surprises in the future.

And for the average Joe, take a look at your fight log or a screenshot then pick 3-4 targets, do 15-20 fights with each and compare the results with what you had before.