This randomized controlled trial evaluates whether adding a short, structured team-reflection protocol (Tactical Programme for Critical Thinking, TPCT) to regular elite women's underwater rugby training improves tactical efficiency. Both groups complete the same training content and time; the TPCT group uses brief guided discussion during recovery intervals, while the control group uses the same time for passive recovery. Tactical efficiency is assessed using video-recorded 3v3 scrimmages coded with the RUSTAC checklist at baseline and after 6 weeks.

A parallel, two-arm randomized controlled trial will be conducted in an elite women's underwater rugby squad. Players will be allocated 1:1 to TPCT or an active control condition using a computer-generated random sequence. The intervention consists of 18 sessions over 6 weeks (3/week), 2 hours per session, delivered in an outdoor 4 m pool and a marked 10 m × 8 m underwater area. Sessions include a short coach introduction (~15 min), constrained small-sided games designed to elicit target tactical principles, and ≥60 min free-play (≥50% of session) to preserve representativeness and transfer. The TPCT condition embeds ~3 min structured reflection between small-sided bouts using a fixed 5-question protocol aligned to critical thinking operations; the control condition uses equivalent between-bout time for passive recovery/hydration.

Inclusion Criteria:

• Female elite underwater rugby players aged ≥18 years.
• Officially rostered members of the participating high-performance team/squad.
• Regular training participation (minimum 2 sessions per week) in the team's programme.
• Able to complete study procedures at Baseline (Visit 1) and Post-intervention at 6 weeks (Visit 2), including standardized 3v3 scrimmage video assessment.
• Willing and able to provide written informed consent.

Exclusion Criteria:

• Current injury, illness, or medical condition that prevents full participation in regular underwater rugby training during the intervention period.
• Anticipated prolonged absence (e.g., travel/competing/other commitments) that would prevent meaningful exposure to the intervention dose (e.g., missing >20% of sessions).
• Inability to complete the assessment procedures reliably (e.g., unable to participate in the standardized 3v3 assessment or comply with study instructions).
• Declines participation or withdraws consent.

Individual participant data will not be shared publicly because the sample is small and drawn from an identifiable elite sports environment, meaning that de-identified records could still be re-identified when combined with contextual information. In addition, the source materials include video-derived measures, and participant consent was obtained for analysis and publication of aggregated results rather than unrestricted public release of participant-level data. Summary statistics and methodological details will be reported in publications; additional data may be considered on a case-by-case basis under a data-use agreement and applicable ethics constraints.

Participants and coaches cannot be blinded due to the behavioural nature of the intervention. Tactical performance is captured on video and coded by independent assessors who are blinded to group allocation and assessment time point. Videos are anonymised and labelled with neutral IDs; group-specific discussion segments are not included in the footage provided for coding to preserve assessor blinding.