South Korean swimmer Park Tae-hwan was knocked out in the heats in the 200m freestyle at the Rio de Janeiro Olympics on Sunday.

Park finished last among eight swimmers in the sixth and final heat at Olympic Aquatics Stadium in 1:48.06. Conor Dwyer of the United States won the heat in 1:45.95.

Park was 29th overall among 47 swimmers. The top 16 moved on to the semifinals, led by Sun Yang of China at 1:45.75.

Park had won a silver in the 200m free at each of the past two Olympics. His personal best is 1:44.80, set at the 2010 Guangzhou Asian Games.

This was the second straight event in which Park failed to make it out of the heats in Rio. On Saturday, he was eliminated in the heats for the 400m freestyle, where he'd won gold in 2008 and silver in 2012.

Park apologized for not living up to people's expectations, and said he might have overexerted himself trying to atone for his missed opportunity in the 400m free.

"I wanted to put yesterday's 400m race behind me," Park said.

"But I think I was trying too hard to make up for it and my shoulders didn't move the way I wanted them to."

He said he was so frustrated with himself that "I was afraid of looking up at the scoreboard."

When asked if he recalled the last time he finished last in any race, Park said, "I didn't want to come out of the pool."

Park's travails leading up to the Rio Games have been well documented. He was originally under a Korean Olympic Committee ban for his doping history, and had to win an appeal at the Court of Arbitration for Sport to earn his Olympic eligibility.

Between his 18-month doping ban and a drawn-out legal battle with the KOC, Park entered only two competitions and had much less time to train than others.

Park said during his two-week training camp in Jacksonville, Florida, before Rio, he was able to regroup mentally.

Yet the one thing he couldn't change was the fast-evolving world of swimming.

"This was my first major event in about two years (since the 2014 Asian Games), and I didn't know much about young, rising swimmers," he said. "I think the times have changed, and the guys are going all out in the heats. The competition is much stronger than in 2012 or 2013."

Park is slated to compete in the 100m and 1,500m freestyle in Rio. He said he will discuss with his coach, Duncan Todd, whether he will stick to the original schedule, and added, "My job is to do my best at each and every race."

"This isn't the end of my swimming career," Park went on. "I hope this will all end up being good experience for myself." (Yonhap)