Cda is the coefficient of drag area and is applied in triathlon and cycling. It is a multiplication of the coefficient of drag (CD), representing how aerodynamic the bike and cyclist are, with the frontal area (A) in the direction of the air. The smaller the CDA, the better aerodynamics. That is, with the same effort, you can ride faster, or with reduced effort, maintain the same speed.
Those athletes attempt to minimize their CDA through adjusting their bike configuration, donning specialized gear such as helmets, wheels, and body suits, and adopting an optimal body position. Typically, they test it in the wind tunnels or on roads with power meters and speed gauges. Lighter weight assists with climbing, but in flat races or extended time trials, CDA is what counts.
