Validity of the Evaluation of Posture and Movement by a New Tri-axial Accelerometer: Judgement Criteria, Sensitivity and Specificity

[Purpose] The objective of this study was to investigate the validity of evaluation of posture and movement by a new tri-axial accelerometer (DynaPort MoveMonitor: DMM). [Subjects and Methods] Twenty-six healthy young university students cycled and the accuracy of the judgement of cycling by DMM was evaluated. The students also performed sitting, standing, walking, and stair walking, and these activities were recorded by DMM and a video camera. We compared the times measured by DMM and the times measured on video, and examined the sensitivities and systematic errors using Bland-Altman analysis. [Results] Cycling was judged correctly at about 30% of the time. The sensitivities of walking and stair walking were over 80%. The sensitivity increased to 88.5% for the static actions of sitting and standing together. [Conclusion] Cycling was judged by DMM correctly about 30% of the total cycling time, and the times of sitting and standing were correctly judged as static actions.