## 4 Discussion  
The aim of the study was to analyze the differences and relationship between on-ice and off-ice performance in elite ice hockey players of different ages and skill levels. As expected, we found significant differences in all on-ice and off-ice tests in the different age groups except for the first six meters in the 30 m on-ice skating test. Young adult players (under-20) are heavier and taller, jump higher, sprint, and skate faster compared to junior (under-17) and youth (under-15) elite male ice hockey players (Table 1). In previous ice hockey studies, similar results were found in on-ice and off-ice tests between different skill levels and ages [14; 15; 16]. Body height, body mass, and 30 m on-ice skating performance in the under-20 players in the present study (Table 1) was quite similar to those found in elite male Danish under-20 players (body height: 1.79 \(\pm\) 0.06 m, body mass: 75.7 \(\pm\) 10.1 kg, 30 m on-ice skating time: 4.38 \(\pm\) 0.16 s) but lower compared to elite male Finish under-20 players (body height: 1.80 \(\pm\) 0.07 m, body mass: 78.6 \(\pm\) 8.4 kg, 30 m on-ice skating time: 4.12 \(\pm\) 0.12 s) [14]. The differences in skating may be due to different factors. One factor is the skating performance of the athletes. In the Ice Hockey Under-20 World Championship 2019 in Vancouver, Canada, Finland (world champion) placed higher compared to Switzerland (4 th place) and Denmark (10 th place). Another consideration when comparing cross-sectional data of elite athletes is the time of the  
Figure 3: Linear regression analysis scatter-plot of the specific overall skating performance test (SOSPT) and (**A**) 30 m on-ice skating, (**B**) 30 m off-ice skating, (**C**) 30 m off-ice sprinting, (**D**) 6 m on-ice skating, (**E**) 6 m off-ice skating, and (**F**) 6 m off-ice sprinting time separated by age groups into under-20, under-17, and under-15 players. (\(p<\) 0.001 **; \(p<\) 0.01 **; \(p<\) 0.05 *). competitive season when testing occurs. In both studies described above, the participants were tested during the preseason period; however, in the present study, the participants were tested shortly after the preseason summer training that focused more on vertical power training and less on horizontal force generation needed for fast skating. We suggest that the different training focus may have contributed to the higher CMJ height in the under-20 players of the present study (Table 1) compared to the Danish (0.39 \(\pm\) 0.04 m) and Finish (0.43 \(\pm\) 0.05 m) results [14]. The best tests to discriminate (\(p\) < 0.001, \(F\) > 19.0, significant differences between every group) between the different age groups in the present study were the CMJ (vertical power), standing long jump (horizontal power), 30 m off-ice sprinting test, and the SOSPT. To reduce time and physical load in the testing procedures in ice hockey, we advocate using only these tests in future studies, or by sport clubs and national federations. This is due to the high correlations (\(R\) = 0.75-0.85) between the 30 m off-ice sprints, 30 m off-ice skating, and 30 m on-ice skating test. However, the test with the strongest results (\(F\) = 56.01) in the present study was the SOSPT. As depicted in Table 1, there was no overlap of the SOSPT 95% confidence intervals between the different age groups. The SOSPT can be completed in any standard hockey Fink in the world and the equipment needed to complete the test such as cones, a dummy, mat, stick, and a standard hand-held stopwatch are readily available. Considering previous studies in ice hockey [6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16], the SOSPT including all specific movements (starts, stops, crossovers and turns) utilized in the on-ice tests of these studies. We propose that the SOSPT is also suitable to measure performance in the subjects of these studies. We propose utilizing the SOSPT for the selection process in clubs and federations, in addition to as a tool to monitor performance development of adolescent and adult ice hockey players of different skill levels.