centenarian – n. a person who is 100 years old or older

endurance – n. the ability to do something difficult for a long time

freestyle – adj. a competition (such as a swimming race) in which the competitors are allowed to use different styles or methods

category – n. a group of people or things that are similar in some way

backstroke – n. a way of swimming in which a person floats in the water facing upward while kicking the legs and rotating the arms; also : a race in which the swimmers do the backstroke