Player speed

I have noticed that my opponents running backs just blow by my defensive backs like they are standing still. I look at the speed and acceleration stats on the players and they are very close. Why is the such a huge difference in speed with players with very similar stats?
possibly playing with a higher rhythm like do you notice if they get tired at the end?
It could also be that their attack speed is set much higher than your defense speed.
qBaLL the Horrible

I thought about that so I set my defense speed to a high level. I did not see much difference. I will keep experimenting.
I misunderstood rhythm. In real football rhythm usually means the pace (no huddle/hurry up offense) and sequence that plays are run. It has nothing to do with individual players. I will work with my newfound information.
Just be careful with setting rhythm too high, it causes an increase in injuries
It is the rhythm setting for sure. Thanks for the help.