TOKYO -- Japan's Ai Miyazato says she has decided to quit the LPGA Tour at the end of the season because she lost her motivation for the sport after years of struggling to win again.
A former world No. 1 who captured 25 professional titles during her career, Miyazato has not won a tournament in five years and said that lack of success diminished her drive to keep going.
"I've been struggling to maintain my motivation for the past four or five years," she told a news conference in Tokyo on Monday, three days after the LPGA announced her decision to retire. "Being a professional is all about results, and lately I wasn't able to achieve good results."
Miyazato joined the LPGA Tour in 2006 and has earned more than $8 million in her career but has fallen down the rankings. She does not have a top-10 finish this season and had only one last year.
There were rumors in the Japanese media that Miyazato was retiring because she was getting married, but the 31-year-old said she has no plans to tie the knot and that her real reason for quitting was somewhat less romantic.
"I've found it hard to stay focused even in training, which I could always do before," she said.
Miyazato does not have a major title but is one of only nine players to make it to No. 1 since the women's world golf rankings began in 2006.
Her nine LPGA Tour victories all came between 2009 and 2012, and five of them were in 2010, when she was No. 1 three times for a total of 11 weeks.
Women's golf had been dominated by Annika Sorenstam and Lorena Ochoa in the years prior to Ochoa's retirement from full-time golf in April 2010. Miyazato was in her prime that year, winning four of the first nine LPGA Tour events she played.
She also won 15 times on the Japanese LPGA and won the World Cup of golf in 2005, but her most recent LPGA Tour event was the Lotte Championship in April, when she finished tied for 34th.