Cycle Ergometer Work Rate Calculator
Calculated Results:
Work Rate (kpm/min): 0
Power Output (Watts): 0
How to Calculate Work Rate on a Cycle Ergometer
In exercise physiology, measuring the work rate (power) on a cycle ergometer is essential for determining aerobic capacity, caloric expenditure, and prescribing exercise intensity. Unlike a standard bicycle, a cycle ergometer allows for precise control and measurement of resistance.
The Basic Formula
The work rate on a friction-braked cycle ergometer (like the Monark 828E) is calculated using the following variables:
- Resistance (Force): The amount of tension applied to the flywheel, measured in kiloponds (kp) or kilograms (kg).
- Distance (Flywheel Travel): The distance the flywheel moves in one pedal revolution. For most standard Monark ergometers, this is 6 meters.
- Cadence (RPM): The speed at which the subject pedals, measured in Revolutions Per Minute.
Converting kpm/min to Watts
While kilopond-meters per minute (kpm/min) is a common unit in labs, the standard unit of power is the Watt. To convert from kpm/min to Watts, you divide the work rate by 6.12 (or multiply by 0.1634).
Example: If a person is cycling at 600 kpm/min:
600 / 6.12 ≈ 98 Watts.
Practical Example Calculation
Imagine a subject is performing a submaximal fitness test with the following settings:
- Resistance: 2.5 kp
- Cadence: 50 RPM
- Flywheel: 6 meters per revolution
Step 1: 2.5 kp × 6 m/rev × 50 RPM = 750 kpm/min.
Step 2: 750 / 6.118 = 122.6 Watts.