Canoe slalom racing started in Switzerland in 1933, initially on a flatwater course. In 1946, the International Canoe Federation (ICF), which governs the sport, was formed. The first World Championships were held in 1949 in Switzerland. From 1949 to 1999, the championships were held every odd-numbered year and have been held annually in non-Summer Olympic years since 2002. Folding kayaks were used from 1949 to 1963; and in the early 1960s, boats were made of fiberglass and nylon. Boats were heavy, usually over 65 pounds (30 kilos). With the advent of kevlar and carbon fiber being used in the 1970s, the widths of the boats were reduced by the ICF, and the boats were reduced in volume to pass the gates, and boats have become much lighter and faster.