Campbell River swimmer Ricky Millns completed his charity Ironman this weekend, which he undertook without doing any prior training.

Millns finished the undertaking in less than 20 hours, taking 19 hours, 26 minutes to do the full 3.9 km swim, 180.2 km bike and 42.2 km run. Millns raised over $4,000 for the Campbell River Head Injury Support Society, remarkably because he had only started planning the event one week before he did it.

He posted on Instagram on Sunday after the event, saying that the event had taken a toll on his body. "At about 9 p.m. I was 21 km into the run, and I hurt my knee pretty bad," he posted to his Instagram stories. "I tried to run again, but could barely extend my knee. I decided I needed to walk for a bit. After a while, it became obvious that my run was over and I'd be walking the whole way."

Millns continued, saying that his mom joined him to walk for about six hours.

"Never in my life have I needed to dig deeper than I did for those last six hours," Millns wrote. "My knee is completely shot. Swollen huge. The rest of my body is done ... If my mom hadn't walked that entire way with me there's no way I would've finished it."

Swimming for the University of 91原创 Vikes has helped Millns prepare for difficult challenges. His Vikes coach Ryan Clouston said that "Ricky鈥檚 always been someone who chases new challenges in sport and uses them to not only test his strength of resolve, but also to inspire those around him and show them that anything is possible if you put your mind to it."

Despite Millns' athletic endurance, he said on Instagram that this ordeal was almost too much for him. "If this inspires you to do something great, that is incredible," he wrote on Instagram. "But please, if you do something like this, make sure you train, and train hard.

"Do exceptional thins, but make sure you're prepared because it's not about doing them. It's about the work that goes into doing them in the months and years beforehand."