ENGLEWOOD, Colo. -- Peyton Manning's response regarding his level of focus for the upcoming season was as crisp as the spirals he rifled to Wes Welker and other Broncos receivers during the first practice of training camp.

"I'm all in on 2013," Manning said following the training camp opener Thursday morning. "Guys have put the time in. Had a good season in the weight room with Luke (Richesson), our strength coach, and now is the time to put that work into fruition a little bit."

Just 12 months after all eyes were focused on his return from injury and his debut in Denver, Manning noted that his comfort level was significantly higher on the first day of his second training camp with the Broncos.

"I certainly feel more comfortable," Manning said. "I have more knowledge about how I feel physically and what I can do and certainly of our teammates, our system (and) kind of this Denver Broncos culture."

Manning's physical abilities were on display in one-on-one drills when he lofted a deep spiral that was hauled in by Wes Welker, who made a one-handed, over-the-shoulder catch in the end zone that drew a roaring applause from the crowd.

"We've got a new receiver, Welker, I don't know if you saw him out there today," Manning laughed, noting that working with Welker feels similar to getting to know Eric Decker and Demaryius Thomas last season. "You'd love to have five years to get that timing down. We've got a short amount of time, and that is why every day is really so important."

Manning acknowledged that one particularly important element of training camp is the ability to practice against the first-team defense, which creates a challenging practice environment that enables the team to take greater strides.

"What's great about training camp is it's the only time you can go against your starting defense," Manning said. "We don't do that as much in season, so it's great competitive work and trying to improve. Trying to be a better team than we were last year and be a better team tomorrow than we were today."

And while the desire to improve certainly fuels Manning and the Broncos, the sting of how the 2012 season ended also serves as strong motivation.

A 13-3 regular season record – and 4,659 passing yards and 37 touchdowns from Manning – were all whisked away in the bitter, January air after the Broncos' playoff loss to the Ravens, and that's something Manning believes the team needs to constantly revisit for inspiration.

"We still kind of have a scar from losing that playoff game and I think players need to kind of be reminded of that daily," Manning said. "Use that to drive them, to fuel them to make us a better team. I think that is a good thing to make us a better team and to work hard every day to try to be the best team we can be."

Manning added that his teammates have the right mentality for making the strides they hope to take. 

"Guys are pumped. Guys are ready to put the work in," Manning said. "I think that's the key word -- guys are ready to work. We know how much work we have to put in. We know how much improvement that we still need to make, but guys are excited to put in that work and those are the kind of guys you want to play with."