Iran Occupational Health

Background and aims: Car seats have a significant impact on driver comfort and reduction of postural load on the low back of the driver. The purpose of this study was to compare three common types of car seat in Iran on the driver's fatigue and muscle discomfort.

Methods: Ten participants completed 2 hours of simulated driving for each of the three type of car seat in different days within a week. During driving task, the electrical activity of the lumbar erector spinae muscles were recorded every 15 minutes and discomfort rate measured every 30 minutes by a visual indicator. The RMS, mean frequency (MNF) and median frequency (MDF) were calculated and used to assess muscle load and fatigue. Repeated measure ANOVA was performed to assess the effect of car Seat on muscular activity and fatigue.

Results:  A significant difference found between various types of car seat with regards to subjective measure of discomfort data (p<0.05), MNF parameter of left erector spinae muscle showed approximately significant difference between car seats(p=0.07), however with regards to NRMS and MDF parameters, the difference between car seats is not significant during 2 hours driving in simulation context.

Conclusion: Although the level of activity and fatigue of erector spinae muscles showed no significant difference during two hours of driving, but self reported discomfort in low back muscles suggested a significant difference. Based on the findings of this study, it seems some type of car seats may cause discomfort however there was no significant difference between three types of car seat with regard to fatigue. In order to design of ergonomic car seat further studies recommended.