## 2 Materials and Methods
### Procedures  
After a 15-min individual warm up, each gymnast completed at least four consecutive vaults in a timespan of approximately 15 min. Athletes had a maximum of two attempts per vault. In total, 92 vaults were performed in eight half-day sessions of data collection. For each gymnast, a maximum of four different vaults per vaulting style were analysed (only the vault with the better execution based on an E-score, judged by an expert). Included in the evaluations were 20 Yurchenko (layout: n = 5; 360\({}^{\circ}\): n = 4; 720\({}^{\circ}\): n = 7; 900\({}^{\circ}\): n = 4) and 28 Tsukahara (layout: n = 5; 360\({}^{\circ}\): n = 11; 720\({}^{\circ}\): n = 10; 900\({}^{\circ}\): n = 2) style vaults, with different numbers of rotations around longitudinal axis (Table 1).  
Figure 1: Different vault styles. The different first flight phases of the three most common vault styles in male artistic gymnastics. Left: Handspring; middle: Tsukahara; right: Yurchenko.  
All vaults were captured by 14 Vicon Vantage V5 Cameras (Vicon Motion System, Denver, CO, USA) operating at 120 Hz. Eight cameras were placed at a height of 5.50 m and six were installed at 1.70 m (Figure 2). A measurement volume of 2 m \(\times\) 3.5 m \(\times\) 7 m was calibrated with a measurement error of maximally 2 mm. Thirty-nine reflective markers were attached (with double-sided adhesive tape) to the gymnasts' body, according to Vicon Plug-in Gait full-body model ([PERSON], 2010) (Figure 3). Two markers were added on gymnasts' back in order to help fill gaps in the trajectories of the original Plug-in-Gait markers. In order to calculate the Plug-in-Gait-Model, the following measurements had to be realised:  
* body mass;
* height;
* length of legs (distance from superior iliac spine to lateral malleolus;
* width of ankles (distance from lateral to medial malleolus;
* width of knee at the level of joint gap;
* width of elbows (distance from lateral to medial epicondyle);
* width of wrists (distance from radial to ulnar styloid process);
* thickness of hands in the area of metacarpal bones;
* vertical distance between centre of rotation of the shoulder joint and acromion.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Athlete.**} & \multirow{2}{*}{**Level**} & \multicolumn{4}{c}{**[PERSON] Layout**} & \multicolumn{4}{c}{**[PERSON] Layout**} \\ \cline{3-10}  & & **0\({}^{\circ}\)** & **360\({}^{\circ}\)** & **720\({}^{\circ}\)** & **900\({}^{\circ}\)** & **0\({}^{\circ}\)** & **360\({}^{\circ}\)** & **720\({}^{\circ}\)** & **900\({}^{\circ}\)** \\ \hline
1 & Junior n & x & x & & & & & & x & x \\
2 & Junior n & & & & & & & & x & x \\
3 & Junior int & x & & x & x & x & x & x & x \\
4 & Junior int & & & x & & & & & & \\
5 & Junior n & & & & & & x & x & x \\
6 & Junior n & & & & & & x & x & x \\
7 & Junior int & & & x & x & & & & \\
8 & Junior int & & x & x & & & & & \\
9 & Junior int & & & & & & & & x \\
10 & Junior int & & & & & & & & x \\
11 & Junior n & & & & & & & x & \\
12 & Junior int & & & & & & & x & x \\
13 & Junior int & & & & & & x & x & \\
14 & Elite int & & & & & & x & x & x \\
15 & Elite n & x & & & x & x & & & \\
16 & Elite n & & & & & & & x & \\
17 & Elite int & x & x & x & x & & & \\
18 & Elite int & & & & & & & x & x \\
19 & Elite int & & & & & & & x & x \\
20 & Elite int & x & x & x & & & & & \\ \hline  & Total & 5 & 4 & 7 & 4 & 5 & 11 & 10 & 2 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Number of the different vaults performed by international (int) and national (n) elite and junior athletes in this study vaults (\({}^{\circ}\): degrees of rotation around longitudinal axis during the second flight phase).