The sport of flatwater or sprint canoe and kayak has been in the Olympic games since the Berlin Olympics of 1932. It was a demonstration sport prior to that as early as the 1924 Paris games. The distances raced in the Olympics have changed over time, as well as the number of races permitted. Today, races are over 5000, 1000, 500, and 200 meter distances. Men and women race both kayaks and canoes today.
The United States does not have a large sprint paddling community but does have a current World Champion. Watch Nevin Harrison win gold at the 2019 World Championships in the women’s 200 meter qualifying the United States for a spot in the Tokyo Olympics! (Be sure to watch the replay, too, so you can see her expression. The race is less than a minute.)
In a Kayak, the paddler is seated and uses a double-bladed paddle pulling the blade through the water on alternate sides to propel the boat forward. Kayaks have a rudder to steer the boat and are more enclosed with just a cockpit open. Note that it is permissible to have a cover over the cockpit called a “spray skirt.”
In Canoe events, the paddle has a single-blade and the paddler uses a more upright position by kneeling on one knee with the other leg forward and foot flat on the floor inside the boat; this creates a stable position and allows the paddler to power the boat forward by placing the paddle in the water in front of the boat and pulling the paddle down their preferred side. Canoeists specialize on a side and do not change sides during races. This style of canoeing is also sometimes called Canadian Canoeing as it was Canada that first used high kneeling techniques in international competition.
In competition the number of paddlers within a boat is indicated by a figure beside the type of boat; K1 and C1 signifies an individual Kayak or Canoe race, K2 and C2 pairs, and K4 and C4 quartets. Races are split into nine lanes with lane selection at random in the initial heats. Following the heats lane selection is then based on qualification time: 5 being the fastest to qualify, then 6, 4, 3, 2, 7, 8, 1 and 9.
The short YouTube video below provides a good introduction to Olympic sprint canoe and kayaking.