# The effects of six sprint interval training sessions on aerobic and anaerobic performance in trained swimmers

PMID: 39545180
Journal: Frontiers in sports and active living
Published: 2024
Authors: Dalamitros AA, Tzivanis D, Martín-Rodríguez A, Semaltianou E, Mavridis G, Manou V

## Question

Do six sessions of swimming sprint interval training improve aerobic and anaerobic performance, muscle oxygen saturation, heart-rate recovery, and stroke measures compared with easy swimming?

## Summary

Six sessions of maximal 50 m swimming sprints improved 400 m swim time and repeated-sprint performance in untrained swimmers, but did not significantly improve a single 50 m sprint.

## Population

- Untrained swimmers with prior competitive front-crawl or sprint background but no swimming training for more than 6 months.
- Sample size: 21
- Age: EXP 23.5 +/- 2.6 years; CON 23.1 +/- 2.2 years
- Sex: 14 men and 7 women across groups
- Fitness level: untrained at enrollment, with prior swimming background
- Health status: healthy volunteers with written consent

## Methodology

- randomized controlled pre-post training study
- 3 weeks
- indoor 25 m pool
- Randomized and controlled study design.

## Protocol

- Swimming SIT.
- Modality: front-crawl swimming.
- Work intervals: 50 m maximal front-crawl sprint.
- Recovery: 2 min passive rest between 50 m efforts.
- Sets or repetitions: 4 x 50 m.
- Intensity: maximal intensity with feedback after each 50 m.
- Session duration: 600 m warm-up, 2 min passive rest, then 4 x 50 m with 2 min rests.
- Frequency: 2 sessions/week.
- Program length: 3 weeks.
- Progression: six identical sprint interval sessions.
- Easy swim control.
- Modality: front-crawl swimming.
- Work intervals: 200 m self-paced easy swim.
- Sets or repetitions: continuous 200 m after the same warm-up.
- Intensity: about 120 bpm, monitored every 50 m.
- Session duration: same 600 m warm-up followed by 200 m easy swim.
- Frequency: 2 sessions/week.
- Program length: 3 weeks.
- Progression: no progression reported.

## Outcomes

### T400
Status: improved
The sprint interval group improved 400 m swim time; controls did not.

EXP 327.0 +/- 40.2 to 319.1 +/- 36.9 s, 2.4%, t=3.044, p=0.011, ES=0.879

### RST mean
Status: improved
Repeated 50 m sprint mean time improved in the sprint interval group.

31.0 +/- 3.7 to 30.2 +/- 3.4 s, 2.6%, p=0.026, ES=0.742

### T50
Status: no clear change
Single 50 m sprint performance did not significantly improve.

about 1% change; p>0.05

### HRR1
Status: improved
One-minute heart-rate recovery improved after endurance and sprint tests.

T400 7.9%, p=0.002; T50 4.6%, p=0.005; RST 9.6%, p=0.002

## Practical Insights

- A very short swimming SIT block can improve submaximal/race-distance performance faster than single-sprint speed.
- Pool-based maximal sprints need sport-specific skill, lane space, timing, and feedback.
- For general HIIT content, the structure translates better as repeated maximal efforts with full passive recovery than as a bodyweight template.

## Limitations

- Small sample.
- Untrained swimmers with prior swimming experience, not general adults.
- No blood lactate.
- NIRS measured only after tests because movement prevented real-time measurement.
- Repeated sprint test was not performed in the control group.

## Safety And Adherence

- No adverse events, injuries, or dropout reasons were reported in the extracted NXML passages.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/39545180/) (pubmed)
- [DOI](https://doi.org/10.3389/fspor.2024.1451738) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11560444/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.