## 3 Results
### Simple vs. Difficult Yurchenko and Tsukahara Vaults  
Upon initial springboard contact, difficult compared to simple Tsukahara and Yurchenko vaults (layout vs. 900\({}^{\circ}\)) were performed with up to 12% (\(p\) = 0.44; r = 0.29) and 4% (\(p\) = 0.52; r = 0.20) greater TKE, respectively (Figure 6).  
Figure 6: Comparison of various energy forms between simple and difficult Yurchenko and Tsukahara layout vaults without and with 360\({}^{\circ}\), 720\({}^{\circ}\), or 900\({}^{\circ}\) of rotation about the longitudinal axis during second flight phase (TKE: Translational kinetic energy; PE: potential energy; AKE: Angular kinetic energy; *: \(p\) < 0.05; **: \(p\) < 0.01).  
By the end of the springboard contact phase, there was significantly greater AKE for difficult compared to simple Yurchenko vaults (+10% for layout vs. 900\({}^{\circ}\); r = 0.74). This difference was somewhat smaller between simple and difficult Tsukahara vaults (+8% for layout vs. 900\({}^{\circ}\); \(p\) = 0.64; r = 0.17).  
At initial table contact, PE of difficult Tsukahara vaults was significantly lower than for simple Tsukahara vaults (\(-\)6% for layout vs. 360\({}^{\circ}\), r = 0.52; \(-\)7% for layout vs. 900\({}^{\circ}\), r = 0.73). A similar (non-significant) difference was observed for Yurchenko vaults (\(-\)6% for layout vs. 900\({}^{\circ}\), \(p\) = 0.22, r = 41).  
At table push off, we found significantly lower AKE for difficult Tsukahara and Yurchenko vaults compared to simple vaults (Tsukahara layout 15% greater than Tsukahara 900\({}^{\circ}\), r = 0.54; Yurchenko layout 11% greater than Yurchenko 900\({}^{\circ}\), r = 0.65).  
During the second flight phase, AKE was increasingly greater (+2.4%, +21.4%, and +28.8% compared to layout) for increasingly difficult Yurchenko vaults (360\({}^{\circ}\): \(p\) = 0.46, r = 0.24; 720\({}^{\circ}\): r = 0.77; 900\({}^{\circ}\): r = 0.92). This was also the case for increasingly difficult Tsukahara vaults (+9.4% for 360\({}^{\circ}\) (\(p\) = 0.62, r = 0.47), +22.4% for 720\({}^{\circ}\) (r = 0.79), and +29.4% for 900\({}^{\circ}\) (\(p\) = 0.05; r = 0.73), compared to layout). Further, a linear increase in AKE with increasing number of rotations around longitudinal axis during the second flight phase was observed for both vault groups (Spearman's correlation coefficient: Yurchenko: r = 0.83; Tsukahara: r = 0.99). On average, each additional half rotation (180\({}^{\circ}\)) about the longitudinal axis during the second flight phase required between 5.6% (Tsukahara) and 5.9% (Yurchenko) more AKE. Total energy during the second flight phase was greater for difficult Tsukahara vaults compared to simple ones (+6.0% for 720\({}^{\circ}\) compared to 360\({}^{\circ}\), r = 0.49; +5.2% for 900\({}^{\circ}\) compared to 720\({}^{\circ}\), \(p\) = 0.09, r = 0.49); the comparison was repeated for Yurchenko vaults (+4.2% for 720\({}^{\circ}\) compared to 360\({}^{\circ}\): \(p\) = 0.06, r = 0.57; +2.8% for 900\({}^{\circ}\) compared to 720\({}^{\circ}\): \(p\) = 0.26, r = 0.34). Further, we observed a larger difference of total energy during second flight phase between simple and difficult Tsukahara (layout vs. 900\({}^{\circ}\): +12%, \(p\) = 0.53, r = 0.73) compared to simple and difficult Yurchenko vaults (layout vs. 900\({}^{\circ}\): +6%, \(p\) = 0.09, r = 0.57).