Validity of the Microsoft Kinect for measurement of neck angle: comparison with electrogoniometry

Considering the importance of evaluating working postures, many techniques and tools have been developed to
identify and eliminate awkward postures and prevent musculoskeletal disorders (MSDs). The introduction of the Microsoft
Kinect sensor, which is a low-cost, easy to set up and markerless motion capture system, offers promising possibilities
for postural studies. Objectives. Considering the Kinect’s special ability in head-pose and facial-expression tracking and
complexity of cervical spine movements, this study aimed to assess concurrent validity of the Microsoft Kinect against an
electrogoniometer for neck angle measurements. Methods. A special software program was developed to calculate the neck
angle based on Kinect skeleton tracking data. Neck angles were measured simultaneously by electrogoniometer and the
developed software program in 10 volunteers. The results were recorded in degrees and the time required for each method
was also measured. Results. The Kinect’s ability to identify body joints was reliable and precise. There was moderate to
excellent agreement between the Kinect-based method and the electrogoniometer (paired-sample t test, p ≥ 0.25; intraclass
correlation for test–retest reliability, ≥0.75). Conclusion. Kinect-based measurement was much faster and required less
equipment, but accurate measurement with Microsoft Kinect was only possible if the participant was in its field of view.