Assessment of biomechanical demands and discomfort in drivers to stablish design criteria for truck seats

By modifying the angle of the seat pan, this research aimed to determine the ideal seated posture for drivers of trucks while having the best balance between a lower load on the lumbar spine and the perception of discomfort. Eighteen drivers underwent simulated driving tasks; they operated a video game on cruise mode with steering wheel, pedals and visual demand. Four driving tests were performed in periods of 10 min, which is enough time to make the subject familiar with the seat. After every test, participants had to stand up and walk for 1 min, then exercise for 25 s, allowing the relaxation of the back. This study suggests that a \(5^{\circ }\) seat pan tilt, generates more kyphotic posture and more pressure on the seat, however this tilt together with the position of \(-5^{\circ }\) reported lower values in the perception of discomfort. No significant differences were found between the pressure on the seat (p \(=\) 0.88) and the perceived discomfort (p \(=\) 0.94); Pearson’s coefficients revealed a weak dependence between the pressure on the seat and the perceived discomfort (r = 0.14). Further analysis concluded that some angles of seat pan, have less biomechanical demand while a high perception of discomfort, indicating that positions with less biomechanical load on the spine does not guarantee that those are really comfortable.