## 2 Materials and Methods
### Kinematic Analysis  
A kinematic analysis using an optoelectronic system with infrared cameras (BTS Bioengineering S.p.A., Garbagnate Milanese, Milano, Italy) was performed on the wheelchair basketball players. A total of 11 reflective markers (9.5 mm diameter) were used, positioned at body reference points [19; 20] (see Figure 2 for further details): Acromion, spine, scapula, humerus, forearm, wrist, and five sEMG wireless electrodes (BTS Bioengineering S.p.A., Garbagnate Milanese, Milano, Italy) on the following muscles: pectoral major, deltoid, trapezius, serratus anterior, and teres minor. The ROMs of both shoulders were compared during flexion, abduction, extension, and internal and external rotation, calculating any difference in the scapular movement angle, and at the same time evaluating the sEMG signals of the main muscles involved in the shoulder movement during throwing (see Figure 2) [21; 22; 23].  
We asked all participants to perform maximum flexion, extension, abduction, and internal and external rotation movements, first with the dominant limb and then with the non-dominant limb. The investigator provided instructions to the participants and demonstrated the correct plane of elevation before data collection. Participants were asked to complete the elevation and lowering phases in a controlled manner, aiming to accomplish each phase of the movement (elevation and lowering of the shoulder) in three seconds. If participants performed the movement in a different plane the test was discarded, and a new trial registered. Wheelchair basketball participants were seated in a dedicated chair, allowing participants to hold their arms by their sides in a neutral unobstructed position.  
Before performing electromyography, the skin surface was shaved at the electrode sites, gently abraded, and cleaned with alcohol to reduce skin impedance. The surface electrodes were positioned according to the sEMG for Non-Invasive Assessment of Muscles (SENIAM) recommendations [24].  
Figure 2: Kinematic functional analysis protocol for the shoulder showing 3 consecutive frames of the abduction movement of an athlete. A total of 11 reflective markers (9.5 mm diameter) were positioned at body reference points, as follows: processus spinosus of the seventh cervical (C7), eighth thoracic (T8), and second lumbar vertebra (L2), the acromion process (AC), center of the humerus diaphragsis (Hm), lateral epicondyle (EL), ulnar styloid (US), trigonum scapulae (TS), inferior angle of the scapula (AI), and posterior superior iliac spine (Clsup).  
The raw EMG data were digitally filtered at a frequency bandwidth between 20 and 500 Hz, and the linear envelope EMG integrated activity was calculated to represent the amplitude values of the EMG signals.  
The normalization process was performed according to the maximal voluntary isometric contractions (MVICs). We recorded the sEMG signals for the entire duration of each movement and calculated root mean square (RMS) values.  
Moreover, the acceleration for each propulsion was analyzed on a standard system made of a wheelchair training roller and an inertial measurement unit [25; 26]. The difference between the mean stroke acceleration at T0 and T1 (\(\alpha_{\text{T1}}\)-\(\alpha_{\text{T0}}\)) and the bilateral symmetry ratio (sym) between the dominant arm and non-dominant arm were calculated, where, in the latter case, a value ranging between 45 and 55% indicates symmetry, whereas a value lower than 45% or higher than 55% reflects greater accelerations for the non-dominant or dominant side, respectively [27].  
The propulsion pattern was calculated as the mean of the push trajectory. The length of the trajectory and the area under the curve were obtained to calculate the area/perimeter ratio (APR) as an index of smoothness.