Fatigue assessment of sedentary office workers using smartphones: a preliminary study

Objectives. Smartphone-based gait assessment provides a novel method to evaluate fatigue. This study aimed to examine self-reported fatigue and gait parameters recorded using a smartphone before and after an 8-h work day in bank workers, and identify the relationship between self-reported fatigue and gait parameters. Methods. One hundred bank workers (aged 20-45 years) were tested before and after an 8-h work day using a reaction time test, self-reported fatigue scale and gait test. Spearman correlation coefficient analysis and partial least squares regression were used to identify the relationship between self-reported fatigue and gait parameters. Results. Reaction time and self-reported fatigue increased significantly after work. Gait parameters (step frequency, minimum acceleration, acceleration root mean square, step regularity and step counts) decreased; step time and step time variability increased significantly (p < 0.05). We found a significant correlation between changes (Δ) for Δwork engagement and Δstep frequency (r = -0.20, p < 0.05), Δwork engagement and Δstep time (r = 0.21, p < 0.05), and Δwork tasks and Δstep symmetry (r = -0.20, p < 0.05). Conclusion. This study suggests that step frequency, step time and step symmetry measured using a smartphone have the potential to be used as predictors of work fatigue.