sentences:  In September 2006 at the World Marathon Championships in Tremolat, Shaun competed in both the K-1 event, where he won the gold medal, and the K2 event, where he won the silver medal with his partner Shaun Biggs, over Marathon legend Manual Busto Fernandes and his K2 partner Emilio Merchan Alonso.Two years prior in 2004 Shaun placed third at the ICF Canoe Marathon World Championships in Bergen, Norway.Rubenstein competed at the 2008 Summer Olympics in Beijing, but was eliminated in the semifinals of both the K-1 500 m and the K-1 1000 m events.