## 3 Results and Discussion
### ANOVA: Postures and Driving Factors  
In Table 4, steering wheel inclination is the most highlighted dependent variable, significantly influencing trunk and arm movements. This aligns with the study by [PERSON] et. al. [2], which highlighted steering wheel clearance as a critical factor in the assessment of driver comfort within heavy truck cabins. Specifically, for the trunk, flexion-extension presented a range of \(-13.56\) to \(16.99^{\circ}\) (\(30.55^{\circ}\) absolute), while external-internal rotation had a smaller range of \(-5.17\) to \(3.31^{\circ}\) (\(8.48^{\circ}\) absolute). For the arm, flexion-extension showed a more restricted range of \(33.09\) to \(37.70^{\circ}\) (\(4.61^{\circ}\) absolute), while external-internal rotation exhibited much greater variability, with values between \(-31.1\) and \(19.7^{\circ}\) (\(50.80^{\circ}\) absolute). These results suggest that changes in steering wheel inclination may be more closely related to postural adjustments of the trunk and arm, possibly in response to the need to maintain vehicle control and compensate for the ergonomic driving demands. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Independent** & **Dependent Variable** & **Range (\({}^{\circ}\))** & **Absolute Range (\({}^{\circ}\))** \\ \hline Abduction- & & & \\ Adduction Head & Head & \(-8.12\) to \(-2.18\) & \(5.94\) \\ \hline Flexion- & & & \\ Extension Spine Mass Index & \(-0.38\) to \(6.99\) & \(7.37\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: ANOVA between postures and anthropometric factors. The independent variables are as follows: abduction–adduction and flexion–extension of human body segments: head and spine. The dependent variables are the mass indices of the analyzed segments. Subject variability significantly influenced head movements, particularly abduction-adduction and external-internal rotation. For abduction-adduction, the observed range was \(-10.46\) to \(12.11^{\circ}\) (\(22.57^{\circ}\) absolute), while external-internal rotation presented two distinct patterns: one with a range of \(-25.69\) to \(3.25^{\circ}\) (\(28.94^{\circ}\) absolute) and another more restricted range from \(24.40\) to \(33.81^{\circ}\) (\(9.41^{\circ}\) absolute). These differences may be associated with individual biomechanical factors, such as the head mass index, which has been shown to influence the abduction-adduction angle. The results suggests that specific physical characteristics of the subjects could condition their range of movement, possibly in response to the need to adapt posture to improve visibility of the road and vehicle controls. Steering wheel torque significantly influenced arm movements, suggesting that drivers adjust their posture to compensate for its effect. Specifically, external-internal rotation of the arm presented a range of \(-30.49\) to \(-6.77^{\circ}\) (\(23.72^{\circ}\) absolute), indicating considerable variation in joint posture when interacting with the steering wheel. This finding highlights the significant relationship between steering wheel torque and arm biomechanics, suggesting that drivers modify their joint alignment to maintain control, which could contribute to fatigue in the upper limbs during prolonged driving. Vibration frequency significantly correlated with the flexion-extension movement of the forearm in the sagittal plane, recording an angular range of \(3.76\) to \(16.51^{\circ}\) (absolute