Reliability and validity of sports accelerometers during static and dynamic testing

Area of Science:

• Biomechanics
• Sports Science
• Wearable Technology

Background:

• Accelerometers are widely used in sports science to measure movement and impact.
• The SPI-ProX II is a dual data logger frequently employed for such analyses.
• Assessing the accuracy and consistency of these devices is crucial for reliable data collection.

Purpose of the Study:

• To evaluate the validity and reliability of the SPI-ProX II dual data logger's accelerometry.
• To determine the accuracy and reproducibility of raw accelerometer data from the device.

Main Methods:

• Controlled laboratory experiments were conducted to assess the device.
• Intra- and interdevice reliability were tested for measuring peak gravitational accelerations (g).
• Static and dynamic validity were assessed against a criterion-referenced accelerometer across frequencies of 5 to 15 Hz.

Main Results:

• SPI-ProX II accelerometers demonstrated excellent intra- and interdevice reliability with low coefficients of variation.
• Validity testing revealed significant differences and poor accuracy, with high percentage differences (27.5-30.5%).
• Effect sizes indicated small to medium differences for reliability and large differences for validity.

Conclusions:

• The SPI-ProX II accelerometers exhibit high reliability but poor validity for measuring acceleration.
• Caution is advised when using these devices for absolute acceleration magnitude, especially in high-frequency movements.
• Regular device assessment and manufacturer guidelines for calibration are recommended to mitigate errors.