He didn't even know what they were and wasn't interested.
Yoon would come to learn as an all-natural body builder that he'd have to work harder than opponents who rely on performance-enhancing drugs.
"If you want something, you have to go get it," said the 48-year-old New Milford father of three. "You do what you have to do and you don't complain."
Yoon's late parents ingrained that lesson in him when he was growing up in South Korea.
His dad was a high-power executive left the company in the Eighties to bring the family to the U.S. After moving to Norwood in 1984, his parents took over a dry-cleaning business in Nanuet.
Together, they showed their two sons the way to succeed in life and work.
"They worked six days a week and never complained," Yoon said. "They did what they had to do."
So did he.
Yoon never smoked and only drank when he became of legal age. His parents didn't let him or his brother get into it -- something he's thankful for. Instead, they encouraged their boys to do things the honest way, no matter how difficult.
Yoon was 15 and still living in Texas when his father bought him a bench set. Working out was mandatory for the football players at his high school, and he said it helped him clear his mind and perform better on the field.
He finished his football career at Northern Valley Old Tappan and continued lifting when he started college at Texas Christian University.
"That's when I started seeing changes and felt more confident," he said. "I was able to approach people more and wasn't shy."
It was also the first time he encountered steroids -- particularly the negative effects.
"There were two bigger guys I worked out with and they both used steroids," Yoon said. "And then they stopped...I swear, it looked like they didn't even work out when I saw the difference of doing it and not doing it. I've never had an interest since then.
"I'd rather keep what I already have."
Yoon moved back to the area in 1991 after college and began working out at All Body Fitness Center in Closter. That's where he met professional bodybuilder Kathy Unger.
She taught Yoon how to prep for a show properly, focusing strictly on diet and exercise.
Fitness became more functional for Yoon in the late Nineties, when he joined the NYPD.
In 2000, he transferred to the Palisades Park Police Department, making history as one of the four first Korean-speaking officer in Bergen County. He then joined the county police department, which was later absorbed into the sheriff's office.
"If you want something, you have to go get it."
Yoon says fitness helps him in more ways than one.
"Your physical appearance does say a lot for you during first interaction," said Yoon, who mostly does traffic stops on local highways.
"Because of my appearance I've never had an issue with someone initiating anything," he said. "I carry myself well and I'm confident. I might look intimidating but I'm easygoing and friendly.
"It's built in me. It keeps me composed and helps release stress. It's just good for overall daily living."
Yoon, who lifts five or six days a week, began bringing his kids with him.
He said he's helped his 21-year-old stepson gain 30 pounds of lean muscle and his 19-year-old son become sharper as the starting center for the New Milford High School football team. He hopes to someday do the same for his 6-year-old daughter.
Fitness helps him look younger -- most people don't believe Yoon almost 50 -- but admits he's starting to feel the impact of aging.
He keeps a clean diet preaching moderation -- and, of course, hard, honest work.
"I don't do the exercises that I used to do," Yoon said. "I just train smarter."
Think you're the fittest police officer in Bergen or Passaic counties? Know someone who is? Email clevine@dailyvoice.com to be featured in the new Daily Voice series, "Fit Cops."
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