Rowing is an endurance sport in which boats of 1, 2, 4 or 8 rowers compete in timed races, generally 2 to 5 kilometers in length along a stretch of water. Rowing is what’s called a repetition sport, where athletes use oars to repeatedly take strokes and propel the boat down the course. In order to move a boat efficiently, each stroke must be performed by all rowers in a boat in unison, on both sides of the shell. As a crew becomes more skilled, they are able to take strokes at a faster rate, with more power, and with improved technique. Power, endurance, balance and synchrony are key factors that come into play during a race.