## 4 Discussion  
The presented study showed the variations of the subject-specific anthropometric dimensions from the average for different population groups in the Czech Republic and China as a background for the need for personalized human body models. The study showed variations in all dimensions except the total height, as it is one of the basic parameters for anthropometric modeling. The variation of the Czech adults from the average (Figure 4) was the lowest in all groups and was around 7.54% (8.2% for males and 6.9% for females). This was probably caused by the fact that the reference model was an average European subject, which was close to the adult anthropometric group. The greatest variation was in the shoulder width (6), followed by the wrist circumference (14) and the frontal shoulder height (8). The great variation in the thoracic circumferences and the frontal thoracic height was probably due to the fact that the real shape distribution can be affected by the muscle mass or the breast size of the particular subject. The lowest variation was in the knee circumference (19), followed by the arm circumference (12) and the hip circumference (5), meaning that those dimensions can be well described by average anthropometry. Decreasing the age, there was a slightly greater variation equal to 7.93% (8.15% for males and 7.9% for females) for the Czech adolescents (Figure 5). The adolescents, as well as the adults were well described by the average European subject. The greatest variation here was again in the shoulder width (6), followed by the wrist circumference (14) and the frontal thoracic height (8). Again, all these measures can be affected by muscle mass. The lowest variation was in the knee circumference (19), followed by the waist circumference (4) and the abdominal circumference (3). The average variation for the Czech children (Figure 6) equaled 9.52% (9.57% for males and 9.49% for females). Here, the variation was greater as the children had different anthropometry and segment proportions compared to the adults. However, the variation was not so great with the biggest in the wrist circumference (14), followed by the shoulder width (6) and the ankle circumference (21). The lowest variation was in the head circumference (23), followed by the shoulder length (10) and the thigh length (16). The greatest average variation was seen in the group of Chinese adults (Figure 7) and was equal to 10.86% (13.8% for males and 8.16% for females). This average variation was even greater than in the case of the Czech children, meaning the different anthropometric proportions in the population. The standard deviation showed considerable differences even inside the group. The Chinese anthropometry was different from the European one,  
Figure 12: Subject-specific Czech adult model. Male, 45 y, 176 cm, 85 kg. Front (**left**), side (**middle**), and back (**right**) views. which caused the variation in the dimensions' average. The greatest variation was in the wrist circumference (14), followed by the frontal thoracic height (8) and the back thoracic height (9). The lowest variation was in the chest circumference (2), followed by the neck circumference (15) and the thigh circumference (16). In general, for all groups, the variation was over the average for males, whilst females reported variation under the average. This was probably caused by the anthropometric reference model, which represented both male and female groups, where males were usually more robust compared to females. The lowest variation was usually reached at dimensions that were not affected by the local musculature too much. The personalization algorithm enabled developing a subject-specific human body model just addressing a reference model. The advantage of this approach, e.g., comparing to the 3D body scanning, was a considerable decrease of the time consumption taking into account that only 23 body dimensions were measured without any special devices.