User blog comment:Commander Marko/How 'screwy' the League System is/@comment-11603965-20130929214028/@comment-5901234-20131001121436

I think what MMR does is it raises or lowers the LP that you gain after a game. If your MMR is higher than your LP (its hidden and you have to use some korean site to find out what it is) then you will gain more LP for winning, however if its lower than your LP then you gain less LP for winning. However im unsure how LP fits in when it "resets" every time you move up a division.

Source: Some youtube video i watched one time