CREATE TABLE table_31874 ("Year" FLOAT, "Competition" TEXT, "Venue" TEXT, "Position" TEXT, "Event" TEXT)

What competition was the World Championships before 2011?
SELECT "Event" FROM table_31874 WHERE "Competition" = 'world championships' AND "Year" < '2011'
SELECT "Event" FROM "table_31874" WHERE "Competition" = 'world championships' AND "Year" < '2011'