# Visual Fixations in Basketball Shooting: Differences between Shooting Conditions
## 2 Materials and Methods
Data collection occurred in the same gym, using a game ball inflated to the recommended pressure of 0.62 bar. The size of the ball varied between female and male players in line with official guidelines. All participants wore their regular basketball footwear and practice uniforms. Each collection lasted approximately 60 min. Visual behavior was assessed using Tobii Pro Glasses 3, capturing data at a rate of 50 Hz and outfitted with numerous sensors and cameras to enable eye tracking while allowing the head to move freely. The glasses transmit sensor output to a recording unit via an HDMI cable, where video-based eye tracking takes place. By analyzing the corneal reflection caused by infrared illuminators positioned on the glasses (eight per eye), the system determines the direction of the eye's gaze with an accuracy of 0.6 degrees, recording both eyes at the same time. Tobii presents eye-tracking data within a gaze data structure, encompassing the gaze position (gaze2D) within the scene video frame, 3D gaze locations for both eyes, and pupil sizes and gaze directions for either the right or left eye. The gaze2D variable indicates whether the subject is looking at the scene video frames. Equipped with rechargeable batteries, Tobii Pro Glasses 3 can record for up to 105 minutes per charge. The glasses wirelessly send multiple digital media packets [43]. This equipment measures durations and numbers of fixations, saccades, and eye movement, among other variables. Prior to data collection, the equipment underwent thorough testing, to identify and mitigate any potential issues that could affect data integrity. Analysis of fixation durations (both initial and total) and the frequency of fixations leading up to the moment of shooting (starts when the athlete first gazes at the backboard when the ball is received and ends in the last fixation before the ball is released) was conducted using Tobii Pro Glasses 3's Lab software. Specific regions of interest, namely, the backboard and hoop, were predefined prior to data examination. For fixation analysis, regions of interest (such as the hoop and court) were designated, and a minimum fixation duration of 100 ms was applied; fixations shorter than this duration were categorized as saccades or blinks and excluded from the study [44]. Efficiency was measured using a system that varies between values from 0 to 4, depending on whether or not the ball is converted and whether or not it touches the  
Figure 4: Sequence of methodological procedures. Figure 5: Sequence of shooting to a randomized position (1 to 4), in all shooting conditions (X1, X2, and X3—B, O, or N), also randomized, which was repeated in all shooting positions. hoop [45]. The athlete was not aware of the quantification of each value before collection; they only knew that the effectiveness would be calculated with a scale with values between 0 and 4. The data were analyzed using IBM SPSS Statistics 26.0 (IBM Corporation, New York, NY, USA) [46]. Descriptive statistics for the entire sample were reported as mean \(\pm\) standard error with a 95% confidence interval, median, and percentiles. In statistical analysis, the first (Q1) and third quartiles (Q3) are critical measures that segment a dataset into four equal parts. Q1, the lower quartile, delineates the bottom 25% of data when ordered from lowest to highest, serving as a threshold below which a quarter of the data falls. Conversely, Q3, the upper quartile, marks the threshold below which 75% of the data lies, effectively separating the top 25% of values from the rest. These quartiles are instrumental in assessing data distribution, identifying outliers--using the interquartile range (IQR) between Q1 and Q3--and providing a foundation for comparative analysis. The IQR is a robust measure for variability that helps in pinpointing outliers, defined as data points lying more than 1.5 times the IQR from the quartiles.