Ryan Flaherty didn't want to use the word stubborn to describe Russell Wilson. But he said when the Seattle Seahawks quarterback has conviction in a plan, it can be difficult to change his mind.

So when the pair began to discuss Wilson's offseason training regimen, Flaherty realized he had some work to do.

He has trained athletes in different sports but has become increasingly popular among NFL quarterbacks, having worked with Cam Newton, Marcus Mariota and Carson Palmer.

A year ago, Wilson's focus was clear: He wanted to get faster. While speed will always play a role in Wilson's offseason training, Flaherty wanted him to look at the bigger picture this time around and shift his focus.

"He’s getting to that point where you can’t keep training the way you’ve trained your entire life," Flaherty said. "Because there comes a point in your mid-20s, your late 20s, where your body really starts to change. You can’t continue to beat it down every single offseason in the hopes of getting bigger and stronger and faster, because at some point there’s a breaking point."

"So this offseason, our real focus," Flaherty continued, "as much as it was about keeping Russell in top shape and keeping him fast and all of those things that he wants and needs, it was also really turning the focus to injury prevention and saying, ‘Look, you have not missed a game in four years. You have not even missed a practice. We’re going to keep it that way.’

"So we really turned the focus to keeping his body healthy, his mind right, but really implementing injury prevention as a big, big component into his offseason program."

Russell Wilson figures to be playing at a slightly lower weight than he has the past couple of seasons as a result of a revamped workout regimen. Elaine Thompson/AP Photo

Wilson's durability might be the most overlooked aspect of his success in the NFL. Since entering the league, he has started 74 straight games (playoffs included) and has never missed a practice. He has been sacked 195 times during that span and run with the ball on 462 occasions. But since 2012, every time the Seahawks' offense has come out onto the field in the first quarter, Wilson has been in the huddle.

So why change things now? Wilson has to have been doing something right to stay on the field. Why did Flaherty believe this offseason was the time for the 27-year-old to focus on injury prevention?

"You go back through the years of all the quarterbacks, between generally years four to six is where the majority of the injuries occur," Flaherty said. "And I think a lot of that has to do with guys get into their rhythms, they get into the league, they start to get a feel for it, understand it. But what they don’t understand a lot of times is how their training has to change and evolve as they age.

"You cannot keep training like you did when you were 21 and 22 years old. A lot of people don’t understand that. But you also can’t do the reverse, which is not train. And so, at that age is where I really start to shift the training to where it’s a majority focus on corrective exercises and fixing imbalances. Injuries occur in the body when there’s imbalances."

Flaherty believes in data and quantitative analysis. So when Wilson wanted to know why Flaherty felt so strongly about this specific plan, he was able to show his work. It also helped that Palmer, who has suffered multiple injuries in his career, backed Flaherty up.

"Russell, just starting out, because I got him so young, we’ve been able to address those imbalances," Flaherty said. "His lower body is really balanced, which is huge in terms of injury prevention. When I got Carson, I started training him at 35 years old, there’s a lot of imbalances that we had to correct all last year and last offseason.

"Carson’s like, ‘Dude, don’t do what I did. Really just make sure you follow Ryan’s program. Go with the injury-prevention stuff. It’s so important.’ And so I think that’s one thing for Russell that’s going to be huge. I think he has the possibility based on where he’s at, what his body was like when we started working together, not missing a practice for his entire career, which I think is pretty incredible."

As for the actual training, Flaherty traveled from San Diego to Los Angeles, where Wilson was spending his offseason. His team included a physical therapist and massage therapist. The sessions took place four times a week -- Monday, Tuesday, Thursday and Friday -- and lasted from two to four hours.

Some of the changes Flaherty instituted were subtle.

For example, Flaherty explained that the dominant muscles in an athlete's body always want to take over, sometimes making it difficult to work out the smaller, stabilizing muscles. Previously, Wilson's instructions might have been to do four sets of eight reps for an exercise called the single leg Bulgarian split squat. This offseason though, Flaherty timed the reps and made Wilson take six seconds on his way down and six seconds on his way up.

"What that does is it fatigues the bigger muscles quicker, and then it allows the stabilizer muscles, the smaller muscles, to then be activated, and it forces them to work, which then forces them to grow," Flaherty said.

"A lot of times the reason most people have imbalances is because they don’t train the muscles, the body, in a way to where they fatigue the bigger muscles to where you can really get to the stabilization type -- the smaller muscles that are really important in injury prevention."

Wilson is more inquisitive than many of the other athletes Flaherty has worked with. Oftentimes, athletes show up, trust the trainer and do the work. Wilson constantly wanted to know why. Flaherty provided answers.

The quadriceps, for example, should never be more than three times as strong as the hamstring, Flaherty told Wilson. The tear-drop shaped muscle above the kneecap known as the vastus medialis obliquus (VMO) has to be developed in balance with the rest of the body to limit the risk of ACL tears. And so on. Wilson asked, Flaherty explained, and then they came up with a plan.

When Wilson was asked about his offseason focus, he was vaguer, but he still emphasized lower-body strength.

"That’s the biggest thing for me is having my legs really strong so you take those hits, can step up in the pocket, move quickly, move swiftly," Wilson said. "Still keep my eyes downfield and make those plays."

The Seahawks' offensive line could feature three new starters. And the two returning starters are at different positions. The discussion surrounding Wilson's elusiveness has focused on whether to play at a heavier weight to withstand hits or at a lighter weight to outrun defenders.

"Last year, his coaches were always saying, ‘We want you around 218, 219.’ And they say that because they want him to be able to absorb a lot of the hits he’s going to be taking," Flaherty said.

"The more additional body weight that someone carries in order to take those hits and be able to stay healthy, they’ll naturally lose some speed, because he’s carrying extra weight around. It’s like anybody. You put a weight vest on them and they slow down. So it’s kind of like finding that fine balance."

"After last year’s experience," Flaherty added, "I think he’s back to saying, ‘No, no. I want to be a little bit lighter because I want to be able to get away. I don’t want to take those hits.’ I told him before, ‘If you’re fast enough, you don’t need to take hits. So let’s just work on the speed.’ So his body weight’s going to be a little lower this year, which will be good. He’ll be around 212, which will allow him to be faster. So I think his speed’s going to be a little closer to his first or second year than it was in his third or fourth."

And then there's sleep. Wilson said during last season he sleeps five to six hours a night during the week before upping the number to 10 hours on Fridays and Saturdays before games. Flaherty has tried to convince Wilson more sleep during the week is important, introducing him to people like Cheri D. Mah from Stanford, who is an expert in the field.

The sleep argument is one Flaherty has yet to win.

"He’s a tough one because he has a hard time sleeping," Flaherty said. "His mind goes a million miles per hour constantly. It comes down to just sharing information and getting them around experts in different fields.

"I got him introduced to [Mah], just trying to get him educated and understanding that for him to perform at his best, whether it’s him or any other human being or athlete, it requires more than five to six. So we’ve really tried to focus in on that."

Wilson set career highs in completion percentage, passing yards, passing touchdowns and yards per attempt last season. He led the NFL in passer rating. Since he got into the league, Wilson has had a team around him helping him explore ways to get better. That hasn't changed this offseason, but under Flaherty's direction, the focus of his training has shifted.

"We had such a fiery season last year in a good way, making so many plays, especially through the passing game," Wilson said. "And we want to keep that acceleration going."