Low-Volume High-Intensity Race-Pace Training in Finswimmers

Finswimming is a high-speed aquatic sport in which performance in short and middle-distance events depends on the ability to produce and sustain race-specific velocity. Traditional aquatic training models often emphasise high training volume; however, for events lasting from seconds to a few minutes, race-pace work, neuromuscular quality, and individualised load monitoring may be particularly relevant.

This study follows 5 finswimmers from the Antioquia Underwater Activities League (LASA) during a 9-week low-volume, high-intensity training block. All participants received the same general training approach, but training distances, repetitions, target times, and race-pace references were individualised according to each athlete's main competitive event.

Before the intervention, athletes completed a basic characterisation and a baseline performance assessment using an official competition result. Training target times were estimated from the baseline performance. During the 9-week block, the investigators recorded external load variables, including distance, repetitions, weekly volume, target time, and actual time for each relevant repetition. Internal load were monitored using heart rate and rating of perceived exertion. Pace stability were estimated from repeated times in event-specific distances using descriptive indicators such as mean time, standard deviation, and coefficient of variation.

After the intervention, performance were reassessed in the athlete's main event through an official competition or a comparable standardised control test. Data analysis were focus on individual responses, weekly trends, and descriptive changes from baseline to post-intervention. The study were not include a control group or randomisation; therefore, findings were interpreted as exploratory and non-causal.

• Low-volume high-intensity race-pace finswimming training (Behavioral): The intervention will consist of a 9-week finswimming training block oriented towards race-specific pace. Participants will perform repeated swimming efforts prescribed according to individual target times derived from baseline performance. Training sessions will include event-specific distances, repetitions, recovery periods, and target intensities. External load will be monitored through distance, repetitions, weekly volume, target time, and actual time. Internal load will be monitored using heart rate and rating of perceived exertion. Training volume will be adjusted according to the athlete's event profile and reduced towards the final phase when tapering is required.

Primary outcomes

• Change from baseline in main-event finswimming performance time [Baseline and week 9]: Performance time, in seconds, will be recorded for each participant's main competitive event. The baseline value will be obtained from an official competition result or a standardised control test before the training block. The post-intervention value will be obtained from an official competition result or a comparable standardised control test after the 9-week block. A lower time will indicate better performance.

Secondary outcomes

• Change from baseline in mean swimming velocity [Baseline and week 9]: Mean swimming velocity will be calculated from the performance distance and time in each participant's main event. Velocity will be expressed in metres per second. A higher value will indicate better performance.
• Weekly external training volume [Weekly from baseline to week 9]: External training volume will be quantified as the total metres completed per week during recorded race-pace or event-specific swimming repetitions.
• Weekly mean heart rate during recorded swimming repetitions [Weekly from baseline to week 9]: Heart rate will be recorded during training sessions using a heart rate monitor, sport watch, or equivalent device. Weekly mean heart rate will be reported in beats per minute.
• Weekly rating of perceived exertion [Weekly from baseline to week 9]: Rating of perceived exertion will be recorded using a numerical perceived exertion scale after relevant sets or at the end of the session, according to the predefined monitoring protocol. Weekly mean values will be described for each participant.
• Pace stability during event-specific swimming repetitions [Repeated training sessions from baseline to week 9]: Pace stability will be estimated from repeated swimming times in event-specific distances. The coefficient of variation will be calculated for each participant and distance when repeated measurements are available. Lower values will indicate greater pace stability.

Sex: All, ages: 16 Years to any, accepts healthy volunteers

Inclusion Criteria:

* Finswimmers affiliated with the Antioquia Underwater Activities League (LASA).
* Regular participation in finswimming training.
* A defined main competitive event.
* Availability to complete the 9-week follow-up period.
* Ability to complete high-intensity swimming training according to the regular sport programme.
* Written informed consent from adult participants.
* For participants under 18 years of age, written informed consent from a parent or legal guardian and written assent from the participant.

Exclusion Criteria:

* Active musculoskeletal injury.
* Relevant pain or acute illness at baseline.
* Medical restriction for high-intensity swimming exercise.
* Inability to complete the planned follow-up.
* Withdrawal of consent or assent.
* Insufficient attendance or incomplete records for the main study variables.
* Any condition judged by the research team or coaching staff to compromise participant safety during high-intensity swimming.