Ergometer error and biological variation in power output in a performance test with three cycle ergometers

Area of Science:

• Sports Science
• Biomechanics
• Exercise Physiology

Background:

• Accurate monitoring of physical performance changes is crucial for elite athletes.
• Ergometers are commonly used for performance testing, but measurement error can arise from both the device and biological variation.
• Understanding the sources of error is key to improving testing precision.

Purpose of the Study:

• To quantify the contributions of ergometer error and biological variation to measurement error in cycling performance tests.
• To compare the measurement precision of three different cycle ergometers: Kingcycle, SRM crankset, and PowerTap hub.
• To identify strategies for enhancing the accuracy of performance monitoring in well-trained cyclists.

Main Methods:

• Eleven well-trained male cyclists completed familiarization and three 5-min time trials within two weeks.
• Performance tests were conducted using a racing cycle fitted with SRM and PowerTap, mounted on a Kingcycle.
• Mean power output was simultaneously recorded by all ergometers, and a novel mixed-effects model analysis was applied to log-transformed data.

Main Results:

• The overall measurement errors (coefficient of variation) were: Kingcycle 2.2%, PowerTap 1.5%, and SRM 1.6%.
• Components of error attributed to the ergometers were: Kingcycle 1.8%, PowerTap 0.9%, and SRM 1.1%.
• Biological variation (cyclist component) contributed 1.2% to the overall measurement error.

Conclusions:

• Both ergometer-specific errors and inherent biological variation significantly contribute to the total measurement error in cycling performance tests.
• The PowerTap and SRM ergometers demonstrated higher precision compared to the Kingcycle.
• Optimizing ergometer selection and employing test protocols that minimize biological variation are essential for accurately tracking subtle performance changes in elite athletes.