Fuel can come in many forms, whether it's the kind that propels something or motivates someone to keep going despite the circumstances.
It might be odorless, colorless and tasteless, or it can linger, burn and fester over a long period of time.
With that in mind, try to imagine how University of Alabama sophomore linebacker Dont'a Hightower will feel Saturday at Reynolds Razorback Stadium. It was against Arkansas last year that he took a low block to the knee that ended his season and could have done even more damage to his career.
To refresh your memory he was moving to his right on a short carry by Razorbacks running back Michael Smith when he took the low, but legal, block from pulling senior guard Mitch Petrus. The hit resulted in a torn anterior cruciate ligament, medial collateral ligament and meniscus, known in orthopedic circles as the "unhappy triad."
Still, he and sophomore defensive end Damion Square (ACL) returned faster than expected, somewhat similar to cornerback DeQuan Menzie's amazing offseason comeback from a ruptured Achilles.
"I think both guys have played extremely well," Coach Nick Saban said.
Hightower has always said the right things about the blow, that he didn't use the right technique and so forth, yet not a day has gone by he hasn't either thought about or been affected by that hit. It's apparent on every down as he wears protective braces on both knees.
But when asked about facing Arkansas again, Hightower chose his words very, very carefully this week.
"It means a lot, especially with the injury last year, whatever, them taking me out for the season," he said. "It means more to me than that, this is our first SEC game this year. It's an away game. So it's pretty much an opening statement to the rest of SEC as well as the country."
Think Hightower isn't motivated?
He's "itching" for that first sack of the season and how fitting would it be to happen against the Razorbacks. Additionally, "opening statement" are words that can carry a lot of weight and if the No. 1 Crimson Tide wants every future opponent to think it has no chance against the reigning national champions there's no better way than with an early pummeling of a rival.
Yet that's not where the attention has been this past week, or on Hightower, or even on Alabama topping the conference in total offense and total defense.
Instead, the buzz has been on Arkansas. The Razorbacks are ranked in the top 10 for the first time since 2006, they're the upset flavor of the week and it's been a long time since Fayetteville has hosted a game this big.
Critics are claiming that Alabama can't repeat last year's 35-7 thrashing in Tuscaloosa, that the Crimson Tide's revamped secondary is ready to be exploited. The Razorbacks themselves are practically shouting from the rooftops that they believe they can win (unlike last year) and the defense has made major strides.
"Yeah, we're much better than a year ago," Coach Bobby Petrino said.
Maybe they are. But don't think the Tide hasn't been listening, taking it all in and quietly waiting for Saturday. Actually, Alabama may be even more motivated than the home team.
For example, undefeated quarterback Greg McElroy is again being overshadowed by 6-foot-7 Ryan Mallett, who has been in the national spotlight practically non-stop this week after finally leading a last-minute victory (albeit at Georgia). Mallett was similarly hyped last year and after McElroy clearly outperformed his counterpart admitted that it caused him to play with a chip on his shoulder.
Think it's back?
Mallett is even suddenly hailed as a Heisman Trophy frontrunner and the man to beat should the Razorbacks win Saturday. Think the current holder of the award might have something to say about that?
Speaking of Ingram, think the offensive line hasn't been reminded over and over again that he accumulated only 50 rushing yards during the 2009 game? It wasn't until the following week in Kentucky that he began his amazing run for the Heisman.
"I thought I was ready to step up to the challenge of SEC play," junior center William Vlachos said about last year's game. "That was the worst game I personally played. As a line we didn't play very well."
Alabama has known for six months that Arkansas may be the team to beat in the SEC West. Think Saban and defensive coordinator Kirby Smart don't have some defensive surprises dialed up?
Including his years at LSU, Saban has won five straight SEC openers. He's won the last two games against Arkansas by a combined score of 84-21. The Tide also has No. 9 Florida and No. 12 South Carolina next on the schedule, which could be the toughest three-week stretch any team in the nation faces this season, especially with the Gamecocks enjoying a bye the previous Saturday.
Think the intensity hasn't been ratcheting up?
"Yeah, I think we practiced a little better," Saban said Thursday. "I think guys are a little more attentive in meetings. I think guys have all the respect for teams in the league, especially the team that we're playing. I think their interest level is elevated in terms of what they want to accomplish and try to do.
"I think the preparation has been fairly good, practice has been good. The attention to detail has been good."
Attention to detail.
You don't have to read between the lines to figure out that while one team is trying to show some confidence the other already has a swagger, and anyone who doesn't believe that Arkansas hasn't fueled Alabama's motivations even more, and on many levels, should think again.