South Korea coach Hong Myung-bo warned his squad they will face a physically demanding training camp in Miami to get them in shape for next month`s World Cup after a disappointing home loss to Tunisia this week.
The Koreans set off for America on Friday to continue preparations for their campaign in Brazil, where they will face Russia (June 17), Algeria (June 22) and Belgium (June 26) in Group H.
Expectations have been lowered since Wednesday`s 1-0 home loss, where the Africans exposed some defensive frailties and Hong said there was much work to be done.
"After our latest match, we`ve established what we want to accomplish in training," Yonhap quoted him as saying at Incheon Airport on Friday.
"We will address issues with our organisation. To go up against the world`s best players, our players will also have to work on their physical play and improve their individual skills.
"Training in Miami will obviously be very important. I`ve scheduled some rigorous conditioning drills. We will also work on agility and power."
Joining Hong on the flight was defender Park Joo-ho, who was called up to the 23-man squad on Thursday after left back Kim Jin-su failed to make significant enough progress from an ankle ligament injury.
Park`s own problems in recovering from a foot inflammation had been cited when Hong left him out of the original World Cup squad but the Mainz defender said he was now fully fit.
"I have no problem running or training with the ball in my boots. I could have taken longer to heal but coach Hong and the rest of the staff helped me recover in time," he said.
"I`ve come a long way to make the team, and I admit I am feeling some pressure. I will prepare the best I can to contribute to the team."
South Korea`s best World Cup showing was on home soil in 2002 where they finished fourth.
However, in their seven other appearances at the finals they have only once made the knockout stages, losing to Uruguay in the last 16 in South Africa four years ago.