But the Colorado Avalanche right wing would "get on the ice and get out of the gate quick, and then he'd run out of gas a little bit towards the end of his shift," coach Joe Sacco told NHL.com.
While Stewart still managed to enjoy a career year with 64 points and a team-leading 28 goals in 77 games, the 6-foot-2, 228-pound power forward was determined to improve his physical conditioning and stamina over the summer.
Stewart's hard work is paying off. He's among the NHL's leading scorers with 9 goals -- including three game winners -- and 7 assists in 11 games. The 9 goals tied the Avalanche record for October held by Peter Forsberg and Joe Sakic; his four power-play goals are one more than he scored all last season, and he's averaging 17:33 in ice time, nearly a minute more than he logged in 2009-10.
"This is definitely the best shape I've been in my life," said Stewart, who was rewarded before the season with a two-year, $5.75 million contract. "I probably played close to 235 (pounds) last year. My body fat is down 2 percent and my muscle is up. I think now I have as much energy in the third period as I do in the first."
Stewart trained at Twist Sport Conditioning in the Toronto area, spending 2 1/2 hours there five days each week. His regimen included working with a track coach for an additional 1 1/2 hours two days a week.
"I just really worked on trimming down and getting faster," he said.
Stewart's workout group included his brother Anthony, who plays for the Atlanta Thrashers, and Los Angeles Kings forward Wayne Simmonds.
"We definitely had a great workout group," Chris Stewart said. "It was a do-or-die situation for Anthony this summer; now he's in the best shape of his life, too, and that's probably the reason he's playing so well."
The group concentrated on circuit training and "heavy squats," he said. "We did a lot of core stuff. That was a big thing because I was strong, but I wanted to be strong on one leg, and I added a lot of flexibility, too."
There were diet changes as well. Gone were fast foods like cheeseburgers and French fries, replaced with chicken, fish, fruits and vegetables.
"I really focused on my diet," Stewart said. "I saw a nutritionist, and once you take the time to familiarize yourself with everything, it's all about the right attitude and wanting to do it and seeing the results.
"There's a lot of do's and don'ts, but you have to invest in yourself. I thought it would make me a better player and I feel it's paid off. I feel like no matter how long I've been on the ice I still feel like I can go full speed. After a big power burst, it used to take me a couple shifts to recover."
Stewart's new and improved physique hasn't gone unnoticed by his teammates.
"He looks thinner," Milan Hejduk said. "He's in better shape than he was last year. With his speed and power, he can be a nightmare for defensemen."
Last season nearly turned into a nightmare for Stewart, the Avalanche's first-round pick (No. 18) in the 2006 Entry Draft. Unhappy with Stewart's play and conditioning in the first few weeks of the season, the Avalanche sent him to the Lake Erie Monsters in the American Hockey League.
The demotion lasted only a couple of days because several Avalanche forwards went down with injuries.
"I'd say the turning point was when I got sent down to Lake Erie," Stewart said. "When I came back up I definitely was a lot hungrier. I had a lot to prove. We had a few key injuries and I got a great opportunity to play. I came back up with a new attitude."
Stewart eventually skated on the top line with TJ Galiardi and Paul Stastny. For the most part, he's been there ever since.
"It was a great year, getting the first full year under my belt, playing with Stastny and Galiardi, and getting great time on the power play too," he said. "I had a lot of opportunities and I just have to follow up on it this year."
Sacco has been especially pleased with Stewart's play this season, and he appreciates the effort his budding star put in over the summer.
"The big man can make plays, we all know that," Sacco said. "He's definitely more explosive. I think now his ability to recover quicker has helped him, and that's obviously because of what he did in the offseason. Now he should be able to maintain 30-, 40-second hard shifts and then get the rest and then get back out there and still perform at a high level."
Not that Stewart is taking anything for granted.
"I'm not satisfied," he said. "Definitely I'd say I have a lot of confidence, but I still need to have a good work ethic. I need to play hard every night. That's what I plan on doing."