NORMAN, Okla. -- Former Oklahoma receiver Kenny Stills went to the NFL combine and opened eyes with his time in the 40-yard dash. His 4.38 tied him for fourth fastest among receivers as he displayed speed which was rarely shown during his time in crimson and cream.

But Stills knows he still has plenty of work to do if he hopes to become a high pick in the 2013 NFL draft. How does he know? Because he asked.

“Every team I talk to we try to do a good job of, after every interview, asking them what can we work on?” Stills said following his limited participation in OU’s pro day on Wednesday. “Every team [said] just be prepared to be pressed, every play, at the line of scrimmage. I’ve been working on a lot of MMA stuff, hand fighting, trying to be more violent, more vicious at the line of scrimmage and be able to handle that stuff at the next level.”

The NFL’s elite cornerbacks are getting bigger and bigger as teams try to adjust to bigger receivers like Calvin Johnson, who can create mismatches. Thus physical cornerbacks like Seattle’s Richard Sherman and Arizona’s Patrick Peterson are becoming more valuable.

The progression is forcing NFL receivers to become more physical and more violent at the line of scrimmage. With that goal in mind, Stills has been working out with NFL insider Jay Glazer, the co-owner of MMAthletics who puts NFL players through MMA training in the offseason.

“The MMA stuff has been really good, I’m enjoying that,” Stills said. “To be able to work with Jay Glazer, he’s a total meathead, he loves all that stuff. I hit him as hard as I can and he’s like ‘Yeah!’ It’s been fun for me to release that anger without putting pads on.”

Becoming more physical is not the only thing Stills needed to address since declaring early for the draft. At the combine, Stills answered any questions that NFL scouts might have had about his speed. But there were other questions as well as his off-the-field lifestyle came into question.

“Most of the stuff was character stuff, you know, if I’m a good guy,” he said. “If I really care about football or if I’m more interested in Twitter than actually being good at football. If I’m an alcoholic because I got a DUI, just the off-the-field stuff.”

Twitter was a particular question as Stills, who has more than 45,000 followers, is very active on the social media website.

“With the tweets, it’s more, when are you doing football?” Stills said. “But if a camera followed me around all day and saw when I tweeted and when I was doing football stuff, it would be a huge amount of me working, a little amount on Twitter. I don’t have a problem with it, I just need to get teams to understand that.”

His performance at the combine tends to support his unyielding stance that’s it has been, and always will be, football first.

“If I’m capable of doing things at the combine and what I did today and be on Twitter 24/7, I should be able to be on it,” he said.

In other words, it’s tough to run a 4.38 40-yard dash at the combine if you're just tweeting a lot. If you could, there’d be a lot more college athletes with over 27,000 tweets like Stills.

“I feel like people ask questions,” he said. “And there’s stuff out there that’s pretty obvious, [with regards to] how hard I work.”