## 4 Discussion
However, in the present study, the SOSPT was used as a single test to measure specific performance. The repetition of several SOSPT heats, including recovery breaks, may be a suitable test to measure repeated on-ice performance ability, as reported in previous studies [10; 12; 15; 16]. Measuring physiological performance (blood lactate concentration, heart rate, oxygen uptake) in this repeated on-ice performance ability test may potentially determine the aerobic and anaerobic performance in ice hockey. Consequently, additional studies are warranted. In the present study, there was a clear increase in performance with age in almost all tests. However, our cross-sectional data do not affirm any conclusions about player development, because the increase in performance may be due to two independent factors. First, long-term player development typically results in an increase in performance and, subsequently, better results can be expected in the older players. However, the higher performance by older teams could also be the results of the talent selection process. Players with a low physical performance from the under-15 team were not recruited for the under-17 team. If the newly recruited players perform better compared to the non-selected players, the selection process would also contribute to the better results in the performance tests. Consequently, longitudinal studies are warranted to analyze performance development during adolescence in ice hockey players. The relationship between general physical performance measures and the SOSPT are shown in Figure 2. The influence of jumping performance (CMC, standing long jump, single-leg lateral jumps left and right) to the SOSPT was higher in the under-15 compared to the under-17 and under-20 players, whereas the difference was greatest in the CMJ and long jump test. In youth, individual differences in physical performance are larger in general due to age and physical maturity status [21; 22]. In the present study, the individual differences in the under-15 players were also larger with higher standard deviations and wider 95% confidence intervals, as presented in Table 1. We suggest that under-15 players with a higher physical maturity status performed better, whereas under-15 players with a lower physical maturity status performed poorer in the jumping tests and SOSPT. The phenomenon of biased talent selection is well known in different team sports [23]; however, with an increasing age and the end of puberty, differences in maturation become smaller and ice hockey specific skills become more important. Stronger relationships in the under 15 players compared to under-17 and under-20 players were found between on-ice skating, off-ice skating, and the SOSPT. In young adult male ice hockey players, the specific techniques including starts, stops, turns, crossovers, hitting, passing, and shooting determine performance; from another perspective, the general physical and forward on-ice skating performance is sufficiently trained and differences in the SOSPT are mainly determined by the specific technique. In contrast to the under-20 players, the general physical effect on-ice skating performance has more influence on the specific overall skating performance in under-15 players. We suggest that in the under-15, compared to the under-17 and under-20 players, the vertical and horizontal power play result in a greater role in the specific on-ice overall skating performance. These results are important in the selection and training process of young ice hockey players. However, the stronger correlations in the under-15 players compared to the under-17 and under-20 players may also be the result of enhanced talent selection as players get older. All players were recruited from a single professional hockey team with an elite youth academy but no boarding school. Consequently, the selection of under-15 players was limited to those who live near the training location.