This observational case series examined the barrier-step action in elite futsal goalkeepers. The aim was to describe how this goalkeeper-specific defensive movement was organised in time and how selected body angles were configured during execution. Three male professional futsal goalkeepers with international experience each performed three valid dominant-side trials under standardised indoor conditions. The task involved responding to a standardised low ball stimulus delivered by the coach from the penalty mark at a distance of 5 m.

Video data were recorded using a GoPro Hero 10 camera operating at 240 frames per second and analysed frame by frame in Kinovea. The movement was segmented into three operational intervals: initiation-propulsion, lateral transfer, and terminal support-stabilisation. Projected shoulder, hip, knee, and ankle angles were extracted at two analytically defined instants: the end of Interval 1 and the blocking configuration reached during Interval 2. Descriptive statistics were used to characterise between-goalkeeper variation and within-goalkeeper consistency in the barrier-step action.

This study was designed as an exploratory descriptive observational case series aimed at characterising selected projected two-dimensional kinematic features of the barrier-step action in elite futsal goalkeepers. Given the limited biomechanical description of this goalkeeper-specific defensive movement, the purpose was to provide an initial field-based account of its temporal organisation and selected joint-angle configurations rather than to test inferential hypotheses.

Three male professional futsal goalkeepers with international representation were purposively recruited. Each participant completed three valid dominant-side trials in response to a standardised low ball stimulus delivered by the coach from the penalty mark at a distance of 5 m. To reduce between-trial variability in the initial condition, each repetition began with a standardised movement towards the opposite post. The analytical sequence began only after completion of this manoeuvre.

All trials were recorded using a GoPro Hero 10 camera operating at 240 frames per second. The camera was mounted on a tripod at a height of 0.9 m and positioned 6 m from the movement area, with the optical axis aligned as closely as possible to the primary plane of motion. Because the study relied on single-camera two-dimensional video analysis, all outputs were interpreted as projected image-plane measures rather than true three-dimensional joint kinematics.

For analytical purposes, the movement was segmented into three operational intervals: initiation-propulsion, lateral transfer, and terminal support-stabilisation. Angular variables were extracted at two analytical instants: the end of Interval 1 and the blocking configuration reached during Interval 2. The projected angular variables were shoulder, hip, knee, and ankle angles. Temporal variables included the duration of each operational interval. Video analysis was performed frame by frame in Kinovea by a single investigator, and intra-rater reliability was assessed by repeated analysis after a 7-day interval. Descriptive statistics were used throughout to characterise temporal organisation, angular configuration, and between-goalkeeper variation in the barrier-step action.

Inclusion Criteria:

• Male futsal goalkeeper
• Competing at professional level
• International competitive experience
• Able to perform the standardised barrier-step assessment task under indoor conditions
• Able to complete three valid dominant-side trials
• Provided written informed consent

Exclusion Criteria:

• Failure to meet the inclusion criteria
• Inability to complete the standardised assessment task
• Inability to complete three valid dominant-side trials
• Video recordings in which the full movement sequence or required analytical landmarks could not be identified frame by frame

Elite male professional futsal goalkeepers with international experience who underwent a single-session standardised biomechanical assessment of the barrier-step action.

De-identified individual participant data underlying the reported temporal and projected angular outcomes will be shared, including interval-specific time data, projected shoulder, hip, knee, and ankle angles at the two analytical instants, relative temporal contribution of each interval, and angular change from Interval 1 to Interval 2. Raw video files will not be shared in order to protect participant confidentiality and identity.

De-identified individual participant data, the study protocol, and analytic code will be available beginning 3 months after publication and for 5 years thereafter.

De-identified individual participant data underlying the reported temporal and projected angular outcomes, together with the study protocol and analytic code, will be made available to qualified researchers upon reasonable request to the corresponding author. Requests must describe a scientifically sound secondary analysis and will be reviewed for scientific merit, feasibility, and consistency with ethical and confidentiality restrictions. Raw video files will not be shared in order to protect participant confidentiality and identity.