In 2010, despite a nagging injury Kroyter won the gold medal in the high jump at the Youth (18 or younger) Olympics in Singapore. His jump of 2.24 at the age of 16 at a competition in Moscow in February 2010 remains as of August 2016 the best high jump ever by a European youth under 17 years of age. He was dubbed a "rising young star" at the age of 17 by Allon Sinai of "The Jerusalem Post".