Ergometer

An ergometer is an instrument that measures work performed by a person during physical activity or provides a controlled resistance to movement while recording energy output. The term derives from the Greek ergon, meaning work, and metron, meaning measure. Ergometer devices are used to quantify exercise intensity and energy expenditure and are common in sports science, rehabilitation, and clinical exercise testing.

Common forms include cycle ergometers, rowing ergometers, and arm ergometers. A cycle ergometer places adjustable resistance in the crank mechanism; the user pedals at a chosen cadence, and the device records mechanical work in watts as force is applied over a distance. Rowing ergometers simulate the rowing stroke, providing resistance through magnets, air, or hydraulics, and similarly report power output. Arm ergometers use upper-body resistance for cardiovascular assessment or rehabilitation. Some devices also measure heart rate, cadence, and, in certain tests, oxygen consumption.

Uses of ergometers include standardized assessment of cardiorespiratory fitness, such as cardiopulmonary exercise testing, to determine peak oxygen uptake and ventilatory thresholds. They support training prescription, rehabilitation planning, and research protocols. Ergometer data are often supplemented with metabolic or ventilatory measurements to estimate energy expenditure and exercise intensity.

Operation and calibration are important for accuracy. Power output is typically shown in watts, with one watt equal to one joule per second. Regular calibration against known resistances, verified wheel or crank dimensions, and proper technique are essential for reproducible results. Protocols vary by population and goal, but standardization is a core feature of ergometer testing and training.