# Effects of High-Intensity Interval Training With Specific Techniques on Jumping Ability and Change of Direction Speed in Karate Athletes: An Inter-individual Analysis

PMID: 34887776
Journal: Frontiers in Physiology
Published: 2021
Authors: Ojeda-Aravena A, Herrera-Valenzuela T, Valdés-Badilla P, Martín EB, Cancino-López J, Gallardo JA, Zapata-Bastías J, García-García JM

## Question

Does adding karate-specific HIIT improve jumping ability and change-of-direction speed in cadet karate athletes compared with usual training?

## Summary

In 10 cadet karate athletes, adding 4 weeks of karate-specific HIIT to usual training did not produce statistically significant group-by-time improvements in squat jump, countermovement jump, or change-of-direction speed compared with usual training alone. Individual response analysis suggested some athletes improved, but the study was very small.

## Population

- Cadet karate athletes competing at national or international level.
- Sample size: 10
- Age: 15.2 +/- 1.6 years
- Sex: Mixed sex
- Fitness level: Competitive cadet karate athletes
- Health status: Apparently healthy karate athletes without recent injury or disease

## Methodology

- Randomized controlled training study with inter-individual response analysis
- 4 weeks
- Cadet karate athletes during a transition training period
- Randomized and controlled study design.

## Protocol

- Karate-specific HIIT.
- Modality: All-out karate punch and kick combinations performed in front of a partner.
- Work intervals: 4 seconds.
- Recovery: 8 seconds low-intensity combat stance, with 3 minutes between rounds in weeks 1-2 and 2 minutes between rounds in weeks 3-4.
- Sets or repetitions: 3 rounds of 15 sets.
- Intensity: All-out technique execution during work intervals.
- Session duration: About 20 minutes of HIIT within a 90-minute training session.
- Frequency: 2 sessions per week in weeks 1-2 and 3 sessions per week in weeks 3-4.
- Program length: 4 weeks, 10 HIIT sessions.
- Progression: Density increased by reducing between-round recovery from 3 to 2 minutes and adding a third weekly session.
- Usual karate training.
- Modality: Karate technical and combat training.
- Intensity: Usual training at about RPE 5-6.
- Session duration: About 90 minutes.
- Frequency: Usual training schedule.
- Program length: 4 weeks.
- Progression: No specific progression reported.

## Outcomes

### Main reported result
Status: no clear change
No significant group-by-time interaction was observed for squat jump, countermovement jump, or change-of-direction speed.

### Main reported result
Status: no clear change
No significant group or time effects were observed for the primary performance outcomes.

### Main reported result
Status: no clear change
The HIIT group showed a 15.2% squat-jump increase and 1.7% change-of-direction-speed improvement descriptively, but these did not establish a statistically significant group effect.

### Main reported result
Status: unclear
Responder analysis identified some individual responders, including 2 of 5 HIIT athletes for squat jump and change-of-direction speed.

## Practical Insights

- Very short all-out sport-specific intervals may not be enough to improve jump or change-of-direction performance over only 4 weeks.
- Individual response may vary substantially in small athlete samples.
- Progressing density by reducing recovery is feasible but did not prove efficacy here.

## Limitations

- Very small sample.
- Short intervention.
- Menstrual cycle of female athletes was not controlled.
- Neuromuscular stress was not measured.
- Homogeneity of biological age was limited.

## Safety And Adherence

- No injury events were reported in the extracted full-text sections; eligibility required high attendance.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/34887776/) (pubmed)
- [DOI](https://doi.org/10.3389/fphys.2021.769267) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8650689/) (full text)

## Agent Guidance

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