Club officials say former Japan defender Naoki Matsuda collapsed during training after a cardiac arrest.

Matsumoto Yamaga club officials say the 34-year-old Matsuda was unconscious on his arrival at a hospital.

Club president Hiroshi Otsuki quoted doctors as saying Maysuda's condition was ''extremely severe.''

Matsumoto Yamaga coach Yoshiyuki Kato says Matsuda collapsed after finishing a 15-minute warmup run during training.

Matsuda played 40 times for Japan, including at the 2002 World Cup in Japan and South Korea. He played a total of 385 J-League games for the Yokohama F Marinos from 1995 to 2010.