# Ergonomics Study of Musculoskeletal Disorders Among Tram Drivers
## 2 Materials and Methods
### Anthropometry in Tram Driver Workspace  
Anthropometry, the systematic measurement of human body dimensions, plays a key role in ergonomic design, particularly when it comes to seated work environments such as tram driver cabins [31]. Accurate anthropometric data enables the design of tools, workstations, and vehicle interiors that are aligned with the body proportions of users, reducing the risk of musculoskeletal disorders and improving safety and comfort [32]. In driver-oriented workplaces, improper alignment between body dimensions and cabin geometry can result in awkward, static postures, repetitive strain, and insufficient support. Research shows that professional drivers frequently suffer from lower back pain (56%), knee pain (43.75%), and neck pain (39%) as a result of such mismatches [20].  
In this study, anthropometric data were applied to analyze the ergonomic compatibility of the tram driver's cabin. The data source was the study by [PERSON] et al. (2006) [30], which offers detailed external and internal body geometry of 64 European adults. The subjects were grouped into three morphotypes--Small Women (SmallW), Mid-sized Men (MidM), and Tall Men (TallM)--representing a wide range of body dimensions relevant to European driver populations. According to international ergonomics standards, ergonomic workplace design should accommodate at least 90% of the user population, which is typically achieved by designing for the range between the 5 th and 95 th percentiles [33]. The selected morphotypes correspond approximately to key anthropometric percentiles: SmallW represents the 5 th percentile female, MidM the 50 th percentile male, and TallM the 95 th percentile male, thus covering a broad range of the target population. The study includes comprehensive data on height, limb length, body mass, segment circumferences, and internal skeletal geometry based on 3D stereoradiographic reconstructions.  
This classification enabled the calculation of body segment lengths and masses through a biomechanical method developed by [PERSON] and [PERSON]. Their model is based on a statistical analysis of 200 individuals and uses regression equations derived from radioisotope volume measurements to estimate segmental masses [34,35]. These values were further refined using [PERSON]'s harmonic circle method [34,35], which relates body segment lengths to total body height through a canonical system of proportions based on eight head heights. This approach allows for the estimation of static anthropometric dimensions corresponding to each of the three morphotypes (SmallW, MidM, and TallM), providing a consistent foundation for ergonomic evaluation.  
The application of these methods allowed precise estimation of segmental lengths and postural parameters for seated drivers. These values served as a reference for analyzing spatial congruence between the driver's body and cabin layout, particularly the positioning of the seat, pedals, armrests, and control interfaces. Figure 1 illustrates the wireframe representations of all three morphotypes seated in the tram cabin. The corresponding body segment lengths for each morphotype are presented in Table 1. These visual and numerical representations form the basis for the subsequent biomechanical analyses presented in the study.