VAL DI FIEMME, Italy (AP) — Olympic and world champion Pietro Piller Cottrer has retired from cross-country skiing at the age of 38, after a knee injury last month.

Piller Cottrer broke down in tears as he announced his decision at a news conference at the Nordic world championships on Wednesday.

He says "I've had luck during my career but luck has turned its back on me a bit in the past two seasons. I've realized now's the right time to stop."

The Italian adds that he made the decision last month after he fell and badly injured his knee in a ski-marathon in Val Di Fiemme.

Piller Cottrer was part of the winning relay team at the 2006 Olympics in Turin and also won gold in the 15-kilometer pursuit at the 2005 world championships.