Offense and Iowa haven’t exactly gone together like peanut butter and jelly in recent years.But the Hawkeyes can boast of an NCAA leader in a pretty important category ahead of their Big Ten Conference opener Saturday night against Minnesota in Minneapolis.Kaleb Johnson enters the weekend as the top rusher in FBS with 479 yards through three games. Last week, he rolled up 173 yards and two touchdowns on 25 carries in a come-from-behind 38-21 home win over Troy.The first Iowa running back to rush for more than 100 yards in three straight games since 2015, Johnson says that he’s become a more refined runner in his third season with the Hawkeyes (2-1).”My first two years here, I was so used to just using my speed on people because that’s how it was in high school,” he said. “Now, just me knowing that people are faster than me, it kind of hurt a little bit, because I’m used to just outrunning everybody.”Now, it’s just me knowing that and me putting my strength, using my strength and putting my feet and my head down and just going.”Johnson faces a stiff test on the road this week.The Golden Gophers (2-1) have logged consecutive shutouts since a season-opening, two-point loss to North Carolina. Last week, they eased past Nevada 27-0, limiting the Wolf Pack to 10 first downs and 172 total yards.