# Influences of Sex on Muscle Architecture and Performance in Elite Field Hockey Players
## 4 Discussion  
The aim of the present study was to compare male and female elite Field Hockey players on muscle architecture, EI, and performance, and to study the relationships between these parameters. The main findings were that significant differences exist between male and female players for EI of the VL muscle while no differences were detected on this parameter for the Trap muscle. To the best of our knowledge, this is the first study to compare muscle architecture and performance in male and female elite Field Hockey players. Since in ultrasound imaging, muscle tissue appears black and adipose tissue white, EI is mainly influenced by intramuscular adipocytes [27]. However, some authors have demonstrated that this parameter may be also affected by subcutaneous adipose tissue that may alter adsorption and reflection of ultrasound waves [21]. Thus, these authors suggested applying a correction factor for subcutaneous adipose tissue thickness. In the present study, however, participants were elite Field Hockey players with low %FM (an average of 9.69% and 20.51% for male and female players, respectively) and subcutaneous fat may not have a relevant influence on EI. This is supported by the comparison of the EI corrected for subcutaneous fat (cEI) between male and female players. Studies in which the correction factor was applied involved untrained participants with a %FM between 8.1 and 46.8% [19]. Thus, the difference between male and female players detected in the present study on EI of the lower body muscles may be mainly related to intramuscular adipocytes [26]. The intramuscular fat content may be influenced by the hormonal profile of women that promotes lipogenesis mostly in the abdomen, glutes, and the upper lateral part of the thigh [28]. Thus, the present study shows that the difference in muscle quality \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Assessment**} & \multirow{2}{*}{**Male Group**} & \multirow{2}{*}{**Female Group**} & \multicolumn{2}{c}{**Groups Comparison**} \\  & & & **(\(p\); \(\eta^{2}\); CD)** \\ \hline \multirow{2}{*}{Bench Press 1-RM (kg)} & 77.50 \(\pm\) 20.48 \({}^{\star}\) & 41.13 \(\pm\) 8.15 & \(\leq\)0.001; 0.942; 27.038, 45.689 \\  & 5623.63 \(\pm\) 1960.16 \({}^{\star}\) & 1493.57 \(\pm\) 1381.60 & \(\leq\)0.001; 0.427; 5244.44, 11,697.43 \\  & 476.26 \(\pm\) 74.44 \({}^{\star}\) & 216.47 \(\pm\) 34.87 & 0.002; 0.843; 221.96; 297.61 \\  & Rel 1-RM & 1.07 \(\pm\) 0.30 \({}^{\star}\) & 0.67 \(\pm\) 0.10 & \(\leq\)0.001; 0.448; 0.78, \(-\)0.95 \\  & Rel Pow (w-kg) & 5.26 \(\pm\) 2.30 \({}^{\star}\) & 3.61 \(\pm\) 0.57 & \(\leq\)0.001; 0.186; 3.98-5.05 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Data of the performance assessments. AUC = area under the force-power curve; a.u. = arbitrary units. \({}^{\star}\) indicates a significant difference (\(p\leq 0.05\)) from the Female group. between men and women appears greater in the muscle groups located in the lower limbs (e.g., the VL) than in the upper body muscles (e.g., the trapezius muscle) in elite athletes. Curiously, muscle thickness of Trap and VL were similar between the elite female Field Hockey players evaluated in the present study, and female strength and power athletes previously tested by our research group (0.89 cm and 0.88 cm for elite female Field Hockey players and female strength and power athletes, respectively) [3]. On the contrary, the difference between these athletic populations on VLMT was higher compared to Trap MT (1.22 cm and 1.49 cm for elite female Field Hockey players and female strength and power athletes, respectively) [3]. Consistently, the differences between male Field Hockey players and male strength and power athletes were more evident on VLMT than on Trap MT. As expected, men were stronger and more powerful than women at the bench press, and faster in the 30 m sprint and pro-agility tests.