HELP ME LEARN?

We teach hitting, that is blocking and tackling, on both sides of the ball. We also find that the smaller players, (120lbs.) are usually much faster than the 170lbs. player. If you re-read my post you will notice that I stated that the little players who are 140lbs. or less should play with other little players who are 140lbs. or less. The bigger kids at 150lbs. or more should be able to play with bigger kids who are 150lbs. or more. CAPICE?
Concerning "a matter of physics", how is it that you are able to determine the speed of the two players in your example. In competitions of any sort, inequalities will always exist between contestants no matter how exact you try to make the match-ups equal. Lastly, "the object of the game" has nothing to do with 220lbs. center/fullbacks running over 100lbs. defenders, nor is it about 100lbs. fullbacks being pounded by 220lbs. defensive tackles. THE OBJECT OF THE GAME IS TO HAVE FUN AND HELP PLAYERS BY TEACHING THEM BASICS AND FUNDAMENTALS.
THIS WILL GET THEM TO THE NEXT LEVEL SUCCESSFULLY!