Concurrent validation of magnetic and inertial measurement units in estimating upper body posture during gait

• We validate magnetic and inertial sensors to assess upper body posture during gait.
• The sensors are attached on the head, thorax and shoulder girdle of seven adults.
• We compare postural angles from the sensors to an optical motion capture system.
• Postural angles are comparable between systems.
• Magnetic and inertial sensors are valid to assess upper body posture during gait.

We assessed the concurrent validity of commercially available magnetic and inertial measurement units (MIMUs) for estimating mean postural angles for head flexion, thorax flexion and shoulder girdle elevation during gait in seven healthy individuals. Postural angles estimated with the MIMUs were compared with angles calculated using marker data from a gold standard motion capture system. Coefficients of determination of mean postural angles between measurement systems were 0.82 for head flexion, 0.58 for thorax flexion, and 0.77 for shoulder girdle elevation. Bland–Altman analysis showed good agreement between measurement systems. Intraclass correlation coefficients were 0.9 for head flexion, 0.73 for thorax flexion, and 0.87 for shoulder girdle elevation. Root mean square errors were less than 3° between measurement systems for all body segments. The present findings suggest that the MIMUs tested in this study are valid for estimating head flexion, thorax flexion and shoulder girdle elevation during gait.