Impact of car seat on erectro spine muscles activity, fatigue and discomfort

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