# Effects of high-intensity interval training with an eccentric hamstring exercise program in futsal players: A randomized controlled trial

PMID: 37543767
Journal: Medicine
Published: 2023 Aug 4
Authors: Gómez EM, Atef H, Elsayed SH, Zakaria HM, Navarro MP, Sulé EM

## Question

Does adding Nordic curl eccentric hamstring exercise to HIIT improve intermittent work performance, jump performance, and lower-limb isometric strength in futsal players more than HIIT alone?

## Summary

In 21 adult futsal players, one weekly 4-week HIIT circuit improved intermittent running performance whether or not Nordic curl hamstring exercise was added. Adding Nordic curls did not significantly outperform HIIT alone for jumping, strength, or hamstring/quadriceps ratio, although all participants completed the study and no incidents were reported.

## Population

- 21 adult federated futsal players randomized to HIIT+NC or HIIT only.
- Sample size: 21
- Age: 21.24 +/- 3.14 years
- Fitness level: Federated futsal players
- Health status: Able to complete evaluations

## Methodology

- Randomized clinical trial with two active intervention groups
- 4 weeks
- Futsal club training setting in Valencia, Spain
- Randomized and controlled study design.

## Protocol

- HIIT plus Nordic curl.
- Modality: Loaded/bodyweight circuit plus eccentric hamstring exercise.
- Work intervals: 40 s.
- Recovery: 15 s between exercises; 1 min between Nordic curl sets.
- Sets or repetitions: Circuit completed 3 times; Nordic curl 3 x 10.
- Intensity: High-intensity; exact target not reported.
- Session duration: About 50 min including warm-up and stretching.
- Frequency: 1 session/week.
- Program length: 4 weeks.
- Progression: None reported.
- HIIT only.
- Modality: Same loaded/bodyweight circuit.
- Work intervals: 40 s.
- Recovery: 15 s between exercises.
- Sets or repetitions: Circuit completed 3 times.
- Intensity: High-intensity; exact target not reported.
- Session duration: About 40 min including warm-up and stretching.
- Frequency: 1 session/week.
- Program length: 4 weeks.
- Progression: None reported.

## Outcomes

### 30-15IFT
Status: improved
Both groups improved intermittent work performance.

HIIT+NC 17.59 to 18.09 km/h, p=0.01; HIIT 16.05 to 16.45 km/h, p=0.04.

### Jump
Status: no clear change
Vertical jump performance did not significantly improve.

P>0.05 for vertical jump with and without arms.

### Strength
Status: no clear change
Quadriceps and hamstring isometric strength showed trends but no significant changes.

P>0.05 for strength and H/Q ratio outcomes.

## Practical Insights

- A 40:15 circuit is feasible in a team-sport setting.
- Very low weekly frequency may be enough for small intermittent-fitness gains in athletes but not strength or jump changes.
- Adding Nordic curls needs longer or more frequent dosing to test incremental value.

## Limitations

- Small sample.
- Single-center athlete sample.
- No usual-training or no-training control.
- Only one session per week for four weeks.
- Sex distribution not found in extracted article text.

## Safety And Adherence

- All 21 participants completed the study.
- No incidents were reported during the intervention.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/37543767/) (pubmed)
- [DOI](https://doi.org/10.1097/MD.0000000000034626) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10402967/) (full text)

## Agent Guidance

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