Though they’ll both play in the NFC Championship game on Sunday night, Cam Newton and Carson Palmer are two very different quarterbacks.

Still only 26, Newton is entering his prime years. He’s a 6-foot-5, 245-pound athletic anomaly who can tear apart a defense with both his arm and his legs. The Carolina Panthers made him the No. 1 overall draft pick in the 2011 NFL Draft, and if he plays out his current contract, he’ll be in Charlotte until 2020. He has missed only two games in his NFL career.

Palmer is a 36-year-old whom most analysts thought would be out of the league by now. Standing at 6-foot-5 and weighing 235 pounds, he’s a precise pocket passer but not much of a runner. Never a dual-threat QB, Palmer has had several knee surgeries, which, along with his age, have reduced his mobility even further. He was the first overall pick in the 2003 NFL Draft, but he bounced from Cincinnati to Oakland before settling in Arizona. He missed almost the entire 2008 and 2014 seasons with torn ACLs.

You you won’t mistake these two for twins any time soon, but both have had tremendous seasons up to now. STACK was fortunate enough to spend time with both Newton and Palmer this past off-season, and we got an close-up look at how they prepared for the season ahead. What we found were two very different quarterbacks facing very different challenges, but they did share one common denominator: hard work.

Cam’s Training Camp

Newton entered the off-season with a variety of goals he was looking to check off. One, he wanted to go into the season weighing 245 pounds. That meant he had to spend most of the summer weighing around 255, in anticipation for the inevitable weight loss that occurs during pre-season camp.

Two, he wanted to build stability in his ankle. Prior to the 2014 season, Newton had a “ligament-tightening” procedure performed on his left ankle, and it hampered him throughout the off-season and into meaningful regular season games. Nate Costa, Cam’s trainer since he entered the NFL, commented on his ankle rehabilitation to STACK in July. “His ankle bothered him for the majority of the season last year. Last off-season, we did not run before he went back in August. This year, he feels good but didn’t immediately feel like the stability and mobility were all the way there. We did a lot of work to get him to trust it,” Costa said.

Three, he wanted to build camaraderie with his teammates heading into the season.

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Newton achieved his goals by following a strict training regimen with Costa, typically working out five days a week. He was able to maintain his weight around 255 pounds throughout the off-season with a pescetarian diet, heavy in fish, whole grains and vegetables. He learned to trust his ankle through countless repetitions on drills like Box Jumps and Single-Arm Lateral Sled Pulls. He invited his receivers to train with him for two weeks at the Under Armour Performance Center in Baltimore, building not only athleticism but group chemistry. “It’s not just about getting good work in, it’s about bonding with each other,” Newton said of the group training.

He also refined his core strength and conditioning, since both play a crucial role in his ability to hold up over the grinding NFL schedule. “[His core is] his foundation. He’s naturally gifted as an athlete. He’s gotten bigger, faster and stronger over the years. But I try to get him to go into the season where at Week 15, he feels just as good as he did going into Week 1. Granted, he’s going to be beaten up. But every time you take a hit, if your core is more stable than it was, its not going to be as impactful. You’re going to be able to shake it off and go,” Costa said.

 RELATED: The Cam Newton Workout

The results of Cam’s off-season regimen speak for themselves. He hasn’t missed a game due to injury, and he looks as explosive now as he did back in September. The chemistry he has with his teammates is obvious, and it allows them to play a loose, confident brand of football.

Carson’s Long Road Back

Whereas Newton entered the past off-season with a focus on tightening up nagging issues and preparing his body for a long season, Palmer started from square one. His first order of business was to rehab from the surgery he underwent to repair the torn ACL he suffered in November 2014. Those rehab sessions sometimes lasted seven hours or more, and the repetition and slow progress were tough mental blocks to hurdle.

“You have to be ready to attack every day,” Palmer told STACK in July. “You have to be ready to be mad, and bored, and sick of doing the same thing every day. You just have to know that is what the situation is going to be, and get through it.”

Palmer attacked his rehab with consistency, never missing a single rep—much less an entire day. “Once you’ve made the decision to come back, it’s a mental game. I’ve seen a lot of guys who have knee injuries [who] don’t ever get back. The biggest thing is mindset, knowing that you can’t take a day off,” Palmer said.

RELATED: Carson Palmer’s Grueling Recovery From a Torn ACL 

Soon enough, he was able to begin working out wearing a knee brace. Since Palmer essentially had to start from zero, he saw the off-season as an opportunity to address lingering issues he knew were hurting his game, such as a few shoddy mechanics and a weak core. He even had blood work done to identify deficiencies, and he took vitamins to address those deficiencies. He cut back on carbs and chugged gallons of water every day. He had daily massages to flush out stale blood around his knee and increase circulation. As his strength and speed gradually came back, he worked on his ability to move dynamically in the pocket. He continued to set small goals for himself, achieving each before moving onto the next. “Throughout this, I’ve set one goal, accomplished it, then set the next,” Palmer said. When he got to training camp, his coaches and teammates were shocked to find he looked sharper than ever.

RELATED: Carson Palmer is Making Every Throw in 2015 

Palmer has had a magnificent year statistically, but you only need to watch one play to see how far he’s come. It came at the start of overtime in the Cardinals’ NFC Divisional round playoff game against the Packers. Aaron Rodgers had just thrown a game-tying Hail Mary at the end of regulation, and the Arizona faithful were demoralized. Then Carson Palmer did this:

Larry Fitzgerald took the ball all the way inside the Packers’ 5-yard line, and two plays later the Cards punched it in for the win. That play perfectly demonstrates the chaotic nature of football and how elite players are able to navigate through the storm around them. Just a little over a year after an injury thought by many to be career-ending, Palmer used his surgically repaired knee to bust out a ferocious spin move and win the game for his team. If that play was the final test in his rehab, he passed with flying colors.

Although Palmer’s and Newton’s careers have followed different paths to this point, they both have insatiable work ethics. We’ll see which player can keep his Super Bowl hopes alive this Sunday night when the Cardinals and Panthers clash in the NFC Championship.