## 4 Discussion  
The present study aimed to provide morphological and performance characteristics of elite handball players taking into consideration different playing positions and age categories. We found that players differed between age categories and playing positions for body height, body weight, BMI and BM%, SJ, CMJ, ERS and VO\({}_{\text{2 max}}\). The MM%, CMJ/SJ ratio and HR\({}_{\text{max}}\) differed only between different age categories, while FM% and running velocity on 5 m, 10 m, and 20 m differed between playing positions only. No difference was found between U21 and seniors, whilst U19 differed from them only in body weight and, consequently, BMI. The U17 players' muscle mass and fat mass percentage has been found to be similar but all other body measures differed significantly from their older counterparts. Our results are in line with previous findings [6; 7; 13; 17; 18; 19], showing that anthropometric measurements are characterized by playing positions. Furthermore, these differences were found across the whole sample, regardless of their age. Pivots have been shown to be the tallest and the heaviest in all age categories, supporting previous reports [17; 18; 19]. Taking into consideration pivots' average offence play area, their involvement in low- and high-intensity physical contacts and duels during both offense and defense play [20], their height is very important for greater area coverage, scoring in difficult situations and also for creating scoring opportunities for teammates. Speed and power-related variables showed somewhat different results from anthropometry comparisons. Running velocity, measured at 5 m and 10 m, did not differ between age categories but differed between playing positions. In contrast, the 20 m sprinting performance showed no difference between playing position, however it differed between U19 and U17 backcourts, showing that U19 players were faster. Similar U17-U19 differences in sprinting performance were observed recently by [PERSON] et al. [19], who found a difference between pivots but no other playing position at 5, 10 and 30 m. The jump performance showed playing position differences in the U17 and U19 categories but not in U21 and S, with pivots demonstrating the smallest both SJ and CMJ height in all age categories. Age category differences occurred only when the U17 team was compared to their older counterparts, while no differences were found between U19, U21 and S. These differences were most likely due the maturity [21; 22], experience [10] and anthropometric factors (e.g., body height). The eccentric utilization ratio did not differ between subjects, showing a similar stretch-shortening cycle performance throughout all age and playing position categories. The aerobic capacities were similar for all positions in the S group. The end-running speed achieved in the 30-15\({}_{\text{IFT}}\) differed between playing positions in U21, U19 and U17, whilst VO\({}_{\text{2 max}}\) differed only in the U19 and U17 group. Goalkeepers and wingers were shown to be the slowest and the fastest players in all three age categories, respectively. Only backcourts differed within the age category, with U21 showing better results than U17. In general, we found higher 30-15\({}_{\text{IFT}}\) end-running speeds and VO\({}_{\text{2 max}}\) values when compared to previous research including handball players [3; 16; 23]. The VO\({}_{\text{2 max}}\) values showed to be lowest in the youngest group (U17), with no S, U21 and U19 differences, with the exception of backcourts, where U19 had a smaller VO\({}_{\text{2 max}}\) than S and U21, but larger than U17. Furthermore, the same positional differences were observed for VO\({}_{\text{2 max}}\) in both U19 and U17, with wings showing the highest maximum aerobic capacity. Taking into consideration that wings usually run more than their teammates [20; 24; 25] and that their repeated-sprint ability is required during most counter-attacks [20], we provided further evidence confirming the previous findings by [PERSON] et al. [26].