Manchester United midfielder Shinji Kagawa admits he needs to toughen up.

Kagawa, who only weighs 9st 9lbs, admits he has to grow stronger to be able to compete in English football following his £12million move from Borussia Dortmund.

"I've realised that I need to limber up and strengthen my body," he said.

"There are some tough games coming up. This injury may be due to travel and fatigue but I can get by if I take good care of my body."