# Inter-Individual Variability of a High-Intensity Interval Training With Specific Techniques vs. Repeated Sprints Program in Sport-Related Fitness of Taekwondo Athletes

PMID: 34867471
Journal: Frontiers in physiology
Published: 2021
Authors: Ojeda-Aravena A, Herrera-Valenzuela T, Valdés-Badilla P, Cancino-López J, Zapata-Bastias J, García-García JM

## Question

Does a sport-specific taekwondo HIIT program produce different fitness adaptations and responder patterns than repeated-sprint HIIT in competitive taekwondo athletes?

## Summary

In 12 competitive taekwondo athletes, 4 weeks of regular taekwondo training plus either technical-specific HIIT kicks or repeated sprint HIIT improved squat-jump performance in both groups but did not clearly improve countermovement jump, total kicks, or shuttle-run performance. The technical kick protocol was not statistically superior to repeated sprints.

## Population

- Competitive national/international taekwondo athletes.
- Sample size: 12
- Age: Women 16.8 +/- 2.5 years; men 17.8 +/- 3.8 years
- Sex: 8 men and 4 women
- Fitness level: Competitive taekwondo athletes training at least 3 times per week
- Health status: Injury-free and without neuromuscular disorder

## Methodology

- Randomized two-group training study without a non-training control
- 4 weeks
- Taekwondo training setting
- Randomized and controlled study design.

## Protocol

- Technical-specific taekwondo HIIT.
- Modality: Alternating circular taekwondo kicks.
- Work intervals: 4 s all-out kicks.
- Recovery: 28 s active/dynamic pause; 1 min passive between rounds.
- Sets or repetitions: 3 rounds of 2 min activity.
- Intensity: All-out efforts.
- Session duration: About 10 min HIIT block within a 90 min session.
- Frequency: 3 sessions/week.
- Program length: 4 weeks.
- Progression: No progression reported.
- Repeated-sprint HIIT.
- Modality: Repeated 5 m linear sprints.
- Work intervals: 4 s all-out sprints.
- Recovery: 28 s walking/active pause; 1 min passive between rounds.
- Sets or repetitions: 3 rounds of 2 min activity.
- Intensity: All-out efforts.
- Session duration: About 10 min HIIT block within a 90 min session.
- Frequency: 3 sessions/week.
- Program length: 4 weeks.
- Progression: No progression reported.

## Outcomes

### Squat jump
Status: improved
Squat-jump performance improved significantly in both technical-specific and repeated-sprint groups.

Technical-specific F=8.61, p=0.01; repeated-sprint F=5.51, p=0.04.

### CMJ
Status: no clear change
Countermovement jump did not significantly change.

Reported as not significant.

### Kicking
Status: mixed
Total kicks did not significantly change, and kick decrement index worsened in the repeated-sprint group.

KDI time effect p=0.03; repeated-sprint KDI increased from 3.4 +/- 2.4 to 6.9 +/- 4.3.

### Shuttle run
Status: no clear change
20 m shuttle-run performance did not significantly improve.

Reported as not significant.

## Practical Insights

- Very short all-out intervals can be embedded into sport practice without lengthy conditioning blocks.
- Sport-specific HIIT should not be assumed superior without outcome-specific evidence.

## Limitations

- Small sample
- Short 4-week intervention
- No non-HIIT control group
- Athlete-only sample
- Training-load magnitude not reported

## Safety And Adherence

- No adverse events were reported, but formal safety reporting was limited.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/34867471/) (pubmed)
- [DOI](https://doi.org/10.3389/fphys.2021.766153) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8637814/) (full text)

## Agent Guidance

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