At five feet two inches tall, Jen Welter isn't exactly the type of person you'd expect to see on the sidelines of an NFL football game. But she's never let anyone's preconceived notions stand in the way of her success.
She became a linebackers coach for the Arizona Cardinals during their training camp and the 2015 preseason, making her the first woman to coach in the NFL. Before that, she was a running back for indoor professional team the Texas Revolution and one of only a few women who've played for men's professional teams.
She's also played women's professional football, including for Team USA, which took home two gold medals in in the American Football's (IFAF) Women's World Championship in 2010 and 2013.
Whether it was in the NFL or playing on a men's team, there were many times when Welter was the only woman in the room.
"I was never really successful playing the game their way," Welter says of the men she's played alongside. "And what I finally realized was though I couldn't 'out big' anybody, I could 'out little' and 'out fast' and 'out maneuver' them."
"Once I owned that, my game was different," Welter tells CNBC Make it. "Then I became great."
"I think that translates far beyond the football field," says Welter, who holds a doctorate degree in psychology.
In her new book, "Play Big, " the football coach describes how to achieve success whatever the obstacles may be. Here are three of her top lessons for breaking barriers in your career:
Early on in her career, Welter realized she had a decision to make. She could spend her time worrying about how others perceived her, or she could focus on the job she had to do — which was to play and coach football.
"It wasn't really about being a man or a woman," she says. "It was about being a football player. We had the game in common."
By focusing on her passion for the game and sharing her deep knowledge, Welter was able to show anyone who doubted her that she had what it took to be a great team leader.
"The guys needed to know two things," she said, "that I was a football player, I was there for the right reasons. And I knew the game, loved the game."
"We had that in common," she says. "We were very much the same."
"It was my belief that we could overcome a lot of things with a whole lot of laughter," she says. "That allows you to get comfortable with each other really quickly."
One time, one of her players called her "ma'am" instead of "coach" during practice. The player quickly apologized, visibly worried that he had offended her. Some of the other players turned their heads to look, Welter recalls.
She laughed, made a joke that the player had great "southern manners," and said, "We're fine."
It was a small example of how she turned a potentially awkward situation into one that showed her confidence.
"It was like 'Oh ok, we're good. We can laugh. We can joke together,'" she says.
Welter says she "absolutely" believes that women have to help each other out. But in her career, there have been many times when there didn't happen to be any other women in sight.
The football player knew she could succeed on her own, but recognized how much easier it would be if she had mentors and sponsors, all of whom would have to be men.
"When you're the first woman, and there's no women in the room," she says, "a man has to open the door for you. And that's when it really has to be about progress and working together. Because if it's not in alignment, it's going to be a really tough process."
"As a society," she says, "we have to show them that guys can be the champions for women."
Today, Welter runs a flag football camp for girls along with a number of sports programs geared toward bringing football to youth in under-served communities. She is also a motivational speaker who wants to change the way women are perceived.
One of the most powerful messages she tries to communicate to girls, women and even men is the importance of learning to embrace yourself.
"You have to really realize what it is that makes you different," Welter says, "and own the fact that that's what makes you special."