## 2 Materials and Methods
### Procedure  
The evaluation started with the registration of the individual clinical history. The recorded information included age, height, weight, and lower limb dominance. Limb dominance criteria were defined by the preferred kicking limb [40]. If the subject pertained to the ACL group, they were asked about the laterality of the injured limb, the injury mechanism, and the treatment received. All data collection was completed in one session. Before the EMG and force data collection, the players developed a 5 min aerobical warm-up consisting of relaxed running [8,42]. The players also trained on the tests three times before the real data collection to avoid learning bias. A surface electromyography system (Trigno Avanti, Delsys Europe, Manchester, UK) was used to record data on muscle activation patterns, and a load cell (Trigno Avanti, Delsys Europe, Manchester, UK) was used to measure the muscular force. Muscle activation patterns and muscular force were registered synchronously (Figure 1). [PERSON] et al. instructions for systematizing were followed to ensure the repeatability of the electromyographic examination [43]. Sensors were placed on the skin by a specific sticker after cleaning it with alcohol and cotton wool and waxing the area if necessary [44]. Allocation of EMG sensors was performed following the European Recommendations for Surface Electromyography (SENIAM) [45]. Sensors were placed bilaterally in BF, ST, VM, VL, GMax, and Gm (Figure 2). EMGworks Acquisition software 4.8.0 (Delsys Europe, Manchester, UK) was employed to collect the data. Before performing the tests, all the sensors were calibrated to avoid recording noise and to obtain a relaxed muscle signal between 10 and \(-\)10 \(\upmu\)V. EMGworks Analysis software (Delsys Europe, Manchester, UK) was used to analyze the EMG signal. Players performed the MVIC of the hamstrings (BF and ST simultaneously), the Q (VL and VM simultaneously), the GMax, and the Gm for 3 s. The MVIC contractions from each muscle were repeated three times. Subjects rested for 30 s between each repetition to prevent muscle fatigue [8,42,46]. During the test, players were encouraged, and a computer screen was used to show the signal and provide biofeedback. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **ACL** & **NI** & \\  & **(\(t\) = 11)** & **(\(t\) = 11)** & **\(p\)-Value** \\ \cline{2-4}  & **Mean \(\pm\) SD** & **Mean \(\pm\) SD** & \\ \hline Age (years) & 22.36 \(\pm\) 3.56 & 20.63 \(\pm\) 3.58 & 0.287 \\ Weight (kg) & 59.72 \(\pm\) 5.80 & 61.99 \(\pm\) 6.54 & 0.408 \\ Height (cm) & 162.68 \(\pm\) 7.05 & 163.17 \(\pm\) 6.09 & 0.869 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparative analysis between ACL group and NI group considering age and anthropometric characteristics. The maximal voluntary isometric contractions were performed as depicted in Figure 3. For the Gm, the players were side-lying with the hips in a neutral position with both knees extended. They were instructed to abduct the limb. One fixation was placed on the lateral aspect of the thigh to allow the MVIC [47]. GMax was assessed with the players lying prone, with the hip flexed 30\({}^{\circ}\) and the knee flexed 90\({}^{\circ}\). The fixation was placed on the posterior side of the thigh. The players were instructed to elevate the limb to the ceiling [48]. Hs were measured with the players in the prone position with the knee flexed 45\({}^{\circ}\). The fixation was placed on the posterior aspect of the ankle, and they were asked to bend the knee [42,46]. Finally, for the Q, players were seated with the hips and the knees flexed 90\({}^{\circ}\). The fixation was placed on the anterior aspect of the ankle. The players were asked to extend the knee [42,46,48]. Figure 1: Flow diagram explaining the procedure. (BF) Biceps Femoris, (ST) Semitendinosus, (VM) Vastus Medialis, (VL) Vastus Lateralis, (GMax) Gluteus Maximus and (Gm) Gluteus Medius.