By John Geddie MARSEILLE, France (Reuters) - Iceland have a clean bill of health with captain and long-throw specialist Aron Gunnarsson returning to training on Friday ahead of their European Championship quarter-final against hosts France on Sunday. Midfielder Gunnarsson -- whose throw-ins have created two goals for Iceland including one in their win over England on Monday -- sat out of Thursday's training with a back problem. "He (Gunnarsson) has a little bit of pain coming from his back...and according to the medical team, he shouldn't do anything yesterday," Iceland joint-coach Lars Lagerback told a news conference on Thursday. More...