A wireless accelerometer node for reliable and valid measurement of lumbar accelerations during treadmill running

Area of Science:

• Biomechanics
• Sports Science
• Wearable Technology

Background:

• Root mean square (RMS) acceleration is a key metric for evaluating running mechanics and economy.
• Optical motion capture is the gold standard for movement analysis but is resource-intensive.
• Wireless accelerometers offer a potentially more accessible method for capturing movement data.

Purpose of the Study:

• To assess the reliability and validity of a wireless accelerometer for measuring RMS acceleration during running.
• To compare wireless accelerometer data with optical motion capture measurements.
• To determine the agreement between the two measurement systems across different running speeds.

Main Methods:

• Fifteen healthy participants ran on a treadmill at various speeds (2.22, 2.78, 3.33 m/s).
• A trunk-mounted wireless accelerometer and optical motion capture were used simultaneously.
• Between-trial and within-trial reliability were assessed using intraclass correlations.
• Agreement between systems was analyzed using Bland-Altman plots.

Main Results:

• High between-trial reliability (Intraclass Correlation Coefficient: 0.89-0.97) and excellent within-trial reliability (0.99-1.00) were observed for the wireless accelerometer.
• Bland-Altman analysis showed minimal mean differences (-0.03 to 0.03 g) between the accelerometer and optical motion capture.
• Limits of agreement varied by axis, with vertical acceleration showing the smallest (±0.03 g).

Conclusions:

• The wireless accelerometer demonstrates high reliability for measuring RMS acceleration during running.
• The device shows good agreement with optical motion capture, suggesting validity for trunk acceleration measurement.
• Wireless accelerometers are a viable and repeatable tool for assessing running mechanics and economy.