# Preliminary Analysis of Skin Temperature Asymmetries in Elite Young Tennis Players
## 4 Discussion
### Dominant and Non-Dominant Comparison  
Few studies use IRT in tennis, but some studies analyse Tsk in symmetrical and asymmetrical sports, comparing dominant and non-dominant sides [1; 2; 14]. Tennis has some characteristics that make it asymmetrical [7]. Our hypothesis that higher temperature values would be observed on the dominant side was partially accepted, as asymmetries were observed for the anterior and posterior forearm (after training) and the posterior arm (before training). However, no significant differences were found between both sides in the remaining regions. At baseline, asymmetries higher than 0.5 \({}^{\circ}\)C may indicate physiological dysfunctions [2; 11]. In this study baseline, a difference of 0.3 \({}^{\circ}\)C was only found in the posterior arm. These data verify that the participants did not show any injury or pain, as demonstrated in the pain perception results (Table 1). However, post-training differences in forearms were higher than 1 \({}^{\circ}\)C in both the anterior (1.1 \(\pm\) 0.5 \({}^{\circ}\)C, \(p\) < 0.001, ES = 0.5) and posterior forearm (1.2 \(\pm\) 1.0 \({}^{\circ}\)C, \(p\) < 0.01, ES = 0.5), possibly because of the isometric tension \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Age**} & \multicolumn{2}{c}{**Backet**} & \multicolumn{2}{c}{**String**} & \multicolumn{2}{c}{**Years of**} & \multicolumn{2}{c}{**BMI**} & \multicolumn{2}{c}{\(\Delta\)**General**} & \multicolumn{2}{c}{\(\Delta\)**General**} \\  & & & **Weight** & \multicolumn{2}{c}{**Tension**} & \multicolumn{2}{c}{**Experience**} & & \multicolumn{2}{c}{**Fatigue**} & \multicolumn{2}{c}{**Pain**} \\ \hline  & **r** & **p** & **r** & **p** & **r** & **p** & **r** & **p** & **r** & **p** & **r** & **p** \\ \hline \(\Delta\)**Anterior****Thigh** & \(-\)0.01 & 0.98 & \(-\)0.15 & 0.70 & \(-\)0.53 & 0.14 & 0.21 & 0.59 & 0.37 & 0.33 & 0.11 & 0.79 & 0.11 & 0.79 \\ \(\Delta\)**Posterior****Thigh** & \(-\)0.47 & 0.20 & 0.06 & 0.87 & 0.53 & 0.15 & \(-\)0.50 & 0.17 & \(-\)0.27 & 0.48 & 0.42 & 0.26 & \(-\)0.38 & 0.31 \\ \(\Delta\)**Anterior****Knee** & 0.37 & 0.33 & 0.23 & 0.55 & \(-\)0.26 & 0.50 & 0.58 & 0.10 & 0.59 & 0.09 & 0.41 & 0.28 & \(-\)0.50 & 0.17 \\ \(\Delta\)**Posterior****Knee** & 0.29 & 0.45 & \(-\)0.95 & 0.81 & \(-\)0.20 & 0.61 & 0.43 & 0.25 & **0.81** & **0.01** & \(-\)0.8 & 0.83 & \(\mathbf{-0.81}\)** & **0.01** \\ \(\Delta\)**Anterior****Leg** & \(-\)0.33 & 0.39 & \(-\)0.34 & 0.37 & 0.05 & 0.90 & \(-\)0.14 & 0.71 & \(-\)0.16 & 0.69 & \(-\)0.53 & 0.14 & **0.75** & **0.02** \\ \(\Delta\)**Posterior****Leg** & 0.03 & 0.94 & 0.56 & 0.12 & \(-\)0.33 & 0.38 & 0.14 & 0.73 & 0.30 & 0.43 & 0.33 & 0.39 & \(-\)0.39 & 0.30 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._ \begin{table}
\begin{tabular}{c c} \hline \hline
**ROI** & \multicolumn{2}{c}{**\(\Delta\) Thermal Symmetry (SD)**} \\ \hline Anterior Forearm & 0.8 \({}^{\circ}\)C (0.5) \\ Posterior Forearm & 0.7 \({}^{\circ}\)C (1.1) \\ Anterior Arm & 0.1 \({}^{\circ}\)C (0.6) \\ Posterior Arm & 0.0 \({}^{\circ}\)C (1.2) \\ Anterior Shoulder & 0.2 \({}^{\circ}\)C (0.5) \\ Posterior Shoulder & 0.0 \({}^{\circ}\)C (0.5) \\ Abdominals & 0.0 \({}^{\circ}\)C (0.4) \\  Lumbar & \(-\)0.2 \({}^{\circ}\)C (0.4) \\ Anterior Thigh & 0.0 \({}^{\circ}\)C (0.3) \\ Posterior Thigh & 0.0 \({}^{\circ}\)C (0.4) \\ Anterior Knee & \(-\)0.2 \({}^{\circ}\)C (0.4) \\ Posterior Knee & 0.0 \({}^{\circ}\)C (0.3) \\ Anterior Leg & \(-\)0.1 \({}^{\circ}\)C (0.2) \\ Posterior Leg & 0.0 \({}^{\circ}\)C (0.3) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Mean variation (\(\Delta\)) of thermal symmetry and standard deviation (SD) for each region analysed. needed to support volleys (preventing wrist flexion and extension), to execute prone-supination movements in strokes, and to keep the racket in playing position throughout the hold training session [7; 15].