The six bulls were from the Torrestrella breeding ranch and weigh between 470 kgs to 635 kgs ( about 1,034 pounds to 1,397 pounds ) . NEW : Many runners go to the hospital with injuries . Numerous people fall hard as the bulls try to step over them . Hundreds of thousands gather at nonstop festival in Pamplona .
NEW : Many runners go to the hospital with injuries . Numerous people fall hard as the bulls try to step over them . Hundreds of thousands gather at nonstop festival in Pamplona .