"I just wanted to feel lighter on my feet," Altidore said. "For me, the biggest thing is my health. I don't want to get injured this year, knock on something. I want to keep the injuries at a minimum, and I feel like if I get healthy, I can have a strong season."
Altidore got his year off to an outstanding start with goals in each of the Americans' first two exhibitions in Southern California. He scored in the first half of a 3-2 victory over Iceland last month, making a nimble flick over a prone goalkeeper, before coming up with a dramatic header in the 89th minute of a 1-0 win over Canada last Friday.
"He's hungry," Klinsmann said. "He wants to prove himself, that, 'This is 2016, this is my year.' He looked good the whole camp. He knows there's a huge tournament coming up in June, so he started really on the right foot this year."
Altidore scored 13 goals in 25 games last season for Toronto, which brought him back to Major League Soccer after a seven-year stint in Europe. He felt he could have done even better if he hadn't injured his right hamstring in May and spent the summer slowly recovering, a process that led to him being sent home after the group stage at the Gold Cup.
Altidore also left the 2011 Gold Cup and the 2014 World Cup with hamstring injuries, the latter during the opening match against Ghana.
"I missed the World Cup, and I was looking so much to that World Cup, and I got hurt," Altidore said. "To miss the Gold Cup — I didn't miss it, but I just wasn't fit for it, and that hurt as well. We have the Copa America coming up, so I owe it to myself and to the team to be there and be fit for it."
Altidore is working on a comprehensive fitness program with advice from both the U.S. team and Toronto. He changed his diet and dedicated himself to a renewed focus on stretching, including his first experience with yoga. Everything is designed to minimize his chances for another muscle tear or hamstring woe.
"I just have to be smart in the ways I train, the things I put into my body," Altidore said. "It makes it sound like I wasn't before, but pros understand when I say to be even smarter now, and to be even more disciplined."
Altidore's weight loss cost him some muscle. Although he still looks bulkier than the average NFL defensive back, he's excited about the flexibility and speed he should gain — to a point, that is.
"It's a bit different, because I sometimes feel too light," he said. "I got pushed off the ball a couple of times (against Iceland), and I said, 'Oh, I didn't see that coming.' It's a part of it. Just got to get the muscle a little bit back, but make sure you keep lean and stay light on your feet."
Despite being in the prime of his career, Altidore is closing in on a decade with the American program — he made his debut in November 2007. The time with the national team is somewhat shocking even to Altidore.
"Don't say that, man," he said with a laugh. "Somebody told me that this year, and I can't believe it. Ten years. It's crazy. Hopefully I can go another six, seven. That would be great. Longer than that would be great. Play as long as I can."