An Ergometer (often shortened to “Erg”) is a sophisticated device designed to measure the exact amount of work—or power output—performed by an athlete. While the term is most common in rowing and cycling, it represents any training tool that provides a controlled environment for quantifying effort in Watts. Unlike riding outdoors where wind, terrain, and traffic fluctuate, an ergometer provides a repeatable, laboratory-grade “closed loop” where the only variable is the athlete’s physiological output.
In the modern endurance ecosystem, the erg mode has become the cornerstone of digital training. This feature allows a smart trainer to automatically adjust resistance to match a specific target wattage, regardless of the athlete’s cadence. This precision makes the ergometer the gold standard for Functional Threshold Power (FTP) testing and VO2 Max assessments. By removing the need to shift gears or modulate effort manually, athletes can focus entirely on the physiological stress of the interval. Whether you are navigating a structured session that you customized in our Zwift Live Builder or refining your pedal stroke in a lab, the ergometer is the bridge between raw effort and actionable data.
