Though she always exercised avidly, Ali Wray was worried when she was selected to run with the Olympic Torch in St. Joseph.

“I was afraid I wouldn’t be able to carry the torch the whole way,” Ms. Wray says.

So a little more than a decade ago, she sought out the services of Bob Boyles with Body Image Personal Training.

“I just felt like I needed more personal guidance,” she says.

After working with Mr. Boyles, Ms. Wray has seen her overall fitness improve and her bone density increase.

“It’s been a great experience,” she says.

Personal trainers, a relatively new addition to the fitness world, are becoming a popular investment, according to the American Council on Exercise. According to the council, personal trainers are one of the fastest growing fitness trends. And though many are jumping on the personal training bandwagon, there are a few people who don’t quite understand the need.

“We’re a motivator,” says Brian Cross, personal trainer with the St. Joseph YMCA. “We help people set realistic goals.”

People have various reasons for hiring a personal trainer. According to Mr. Cross, the average person hires a trainer to assist with their weight-loss goals. But many others, he says, like Ms. Wray, come with specific fitness goals. Some want to run a marathon. Others just want to be able to lift their grandchildren.

Trainers begin their initial session by developing a program that will help clients meet these goals. The program, Mr. Boyles says, takes medical history and health concerns into consideration.

After the initial session, people who have hired a personal trainer can expect one-on-one attention during every workout. Mr. Cross says, depending on what the client wants, he’ll even do cardio right alongside them.

Mr. Boyles says he rarely works out with clients. Instead, he prefers to watch and spot them.

“It’s very important to make sure they’ve got the technique down,” Mr. Boyles says.

Training sessions can include running on treadmills, weightlifting, aerobics, calisthenics and even swimming.

For both trainers, regardless of what they do during the training sessions, their job is all about motivation.

“That’s my job,” Mr. Boyles says. “I’m going to help them work out at the level they’re at, and then I’ll push them to the next level.”

How they provide that motivation depends on the trainer and on what the client wants, Mr. Cross says. Television shows like “The Biggest Loser” often show personal trainers as screaming, in-your-face drill sergeants. Mr. Cross says if a client wants that, he’ll do it. But Mr. Boyles says he’s never found that to be a successful approach.

“I think that it’s demeaning, yelling at people like that,” he says. “I encourage people in a positive way, not a negative way.”

Both trainers say they find that balance by building a relationship with their clients. They attempt to encourage accountability without being pushy.

It’s the accountability that Ms. Wray appreciates most.

“You definitely don’t slough off as easily,” she says. “He keeps me hanging in there.”

Eleven years after running the Olympic Torch from Bode Middle School to Faraon Street, Ms. Wray is still working with Mr. Boyles. He even helped her through a hip replacement surgery.

“He’s really kept me on track,” she says. “He doesn’t let you do the same thing over and over again. It’s been great.”