On 59 carries by a running back, ISU has given up only 217 yards for a 3.7 YPC average. That's not bad.
It felt like for all the Coker carries, he would have more than a 4 YPC average. I remember him always falling forward for the extra yard or two and hearing Coker's stats on the post game show, and was surprised by it.
The secondary has played well so far, and the longest run allowed this year is 18 yards.
This team (defense) may be more scrappy than people expected.