When Hopkins joined Whanganui CrossFit with his mother, it was only to turn the tide in a losing battle with his waistline.
"I didn't have any expectations of coming third," he said.
"I just wanted to lose some weight. It's fun, better than any sport I've ever done.
"I started early with junk food but now I'm changing my lifestyle to healthy food, doing more exercise than I've ever done before."
Hopkins showed rapid improvement at the club under the tutelage of coaches Karli Kaea-Norman, Matt Rayner and Megan Wallace, who took him to his second nationals in Hawkes Bay.
"Just keeping going, just empty the tank," was their advice, Hopkins said.
At the event, he had to cycle through six different workout routines, with the best competitors reaching the top standards for each movement involved in that specific activity.
Despite the fact CrossFit Whanganui does not have at rowing machine at their Hatrick Raceway headquarters, the young man powered through the 1000m exercise to be ahead of all the other competitors on the next section.
His third placing came against nine other male and female competitors for his division, amongst the 50 who competed overall.
Kaea-Norman said the nationals were also connected to other national CrossFit events taking place at the same time around the world.
Therefore, because of the time difference, Hopkins was very briefly the third best in the world for his age group.
CrossFit Whanganui holds two classes per day and Hopkins attends every evening session.
There are some major team CrossFit events coming up in April and August, so the teenager is focusing on those.