# The effects of high-intensity interval training at the anaerobic and psychomotor fatigue thresholds on physiological parameters in young soccer players: a prospective study

PMID: 37745255
Journal: Frontiers in physiology
Published: 2023
Authors: Chmura P, Chmura J, Chodor W, Drożdżowski A, Rokita A, Konefał M

## Question

Does HIIT prescribed at anaerobic and psychomotor fatigue thresholds improve physiological parameters and small-sided-game demands in young soccer players?

## Summary

In a one-group prospective study of U17 professional soccer players, four weeks of threshold-based running HIIT improved oxygen uptake and running speed at anaerobic and psychomotor fatigue thresholds. There was no non-HIIT control group, and two players were excluded because of muscle/tendon injuries.

## Population

- U17 professional male soccer players from a Polish second-league club.
- Sample size: 14
- Age: 17.3 +/- 0.4 years
- Sex: Male
- Fitness level: Professional youth soccer players
- Health status: Players with recent surgery or injury were excluded; two were excluded during study because of muscle/tendon injury

## Methodology

- Prospective one-group pre/post study
- 4 weeks
- Professional youth soccer training and laboratory testing

## Protocol

- Threshold-based running HIIT.
- Modality: Running intervals integrated with soccer training.
- Work intervals: Composite efforts of 5:30, 5:45, and 8:15 across three exercises.
- Recovery: 3-minute jog after exercises 1 and 2; 4:30 jog after exercise 3.
- Sets or repetitions: Three specific HIIT exercises per workout.
- Intensity: Running at anaerobic threshold with accelerations to psychomotor fatigue threshold.
- Session duration: 30 minutes for the specific HIIT workout.
- Frequency: 2 sessions per week.
- Program length: 4 weeks.
- Progression: Same three-exercise structure repeated over 8 sessions.

## Outcomes

### VO2 at ANT
Status: improved
Oxygen uptake at anaerobic threshold improved after the intervention.

VO2ANT F=11.665, p=0.005; abstract values 45.9 +/- 3.0 to 48.7 +/- 2.6.

### Speed at ANT
Status: improved
Running speed at anaerobic threshold increased.

VANT F=43.875, p=0.001; discussion reports about +9.8%.

### VO2 at PFT
Status: improved
Oxygen uptake at psychomotor fatigue threshold improved.

VO2PFT F=16.833, p=0.001; abstract values 49.1 +/- 3.4 to 52.0 +/- 3.6.

### Speed at PFT
Status: improved
Running speed at psychomotor fatigue threshold increased.

VPFT F=43.875, p=0.001; discussion reports about +9.0%.

### HR at PFT
Status: no clear change
Heart rate at psychomotor fatigue threshold did not significantly change.

HRPFT p=0.206.

### SSG load
Status: mixed
Small-sided games showed effects for HRmax, mean velocity, and decelerations, but not total distance, max velocity, or accelerations.

HRmax p=0.001; Vmean p=0.007; decelerations p=0.003; TDC, Vmax, and accelerations not significant.

## Practical Insights

- Threshold-based intensity control can individualize running HIIT in trained youth soccer players.
- Small-sided games exceeded anaerobic threshold but did not reach psychomotor fatigue threshold, suggesting game formats may need modification for higher-intensity targets.
- Because there was no control group, the improvements cannot be confidently attributed only to the HIIT program.

## Limitations

- No control group.
- Small sample of young male soccer players.
- Two players were excluded due to muscle/tendon injuries.
- Findings may not generalize beyond developing athletes.
- Authors called for pitch modifications and research in other age and fitness groups.

## Safety And Adherence

- Two participants were excluded during the study due to muscle/tendon injury; relationship to intervention was not clearly specified.
- Heart rate was monitored during training for intensity control.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/37745255/) (pubmed)
- [DOI](https://doi.org/10.3389/fphys.2023.1221121) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10513167/) (full text)

## Agent Guidance

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