Gait stability indicators as extracted by a single wearable inertial sensor in young adolescents during smartphone use

The study of the potential risks associated with the daily use of smartphone in children and adolescents is matter of interest, since smartphones are often used while performing other motor activities like walking and could generate distraction and accidents. The purpose of this study is to check if selected parameters of stability calculated from accelerometer data coming from an inertial measurement unit (IMU) are able to highlight differences in gait stability of young adolescents caused by using a smartphone. Thirty-one adolescents (age 12 years ± 0.5 years) participated in the study. They were asked to walk along a 12-m long straight path under two different conditions: normal walking, and walking using a smartphone (texting activity). Gait signals were acquired by means of a single wireless IMU positioned on the back of the trunk. The acceleration along the three components (AP-Antero-posterior, VT-Vertical and ML-Medio-lateral) were filtered and post processed to extract the following gait stability parameters: the Root Mean Square value (RMS) of each acceleration component, the RMS of the normalized version of each acceleration component (obtained by dividing it by the acceleration magnitude), and the RMS value of the jerk magnitude. The use of the smartphone determines a significant effect on most studied parameters: in particular, during smartphone use while walking the RMS, the jerk RMS, and the normalized component of RMS along the vertical direction decrease, while the normalized component of the RMS normalized along the ML direction increases. The results suggested that the RMS parameters could be good candidates to monitor the gait stability in real-time, and to provide to the subjects information on their potential risk of fall.