# A study of intensity, fatigue and precision in two specific interval trainings in young tennis players: high-intensity interval training versus intermittent interval training

PMID: 29021912
Journal: BMJ Open Sport & Exercise Medicine
Published: 2017
Authors: Suárez Rodríguez D, Del Valle Soto M

## Question

Do continuous 2-minute tennis HIIT bouts and intermittent tennis intervals with brief within-repetition rests differ in intensity, fatigue, shot volume, and precision?

## Summary

Thirteen national-level male youth tennis players completed two sport-specific interval formats. Both produced high heart rate, lactate, and perceived exertion. The intermittent format with short rests inside each 2-minute repetition preserved shot volume and reduced errors compared with continuous 2-minute work periods, suggesting that brief rests can maintain technical quality while keeping intensity high.

## Population

- 13 healthy national-level male tennis players.
- Sample size: 13
- Age: 17 +/- 2 years
- Sex: Male only
- Fitness level: National-level tennis players, 12 +/- 2 training hours/week and 7 +/- 3 years playing experience
- Health status: Healthy

## Methodology

- Within-subject sport-specific interval comparison
- Two weeks, two tests per week with 72 h between tests
- Asturias Regional Sports Centre during preseason
- Controlled study design.

## Protocol

- Continuous tennis HIIT.
- Modality: Tennis cross-court forehand/backhand drill.
- Work intervals: 2 min continuous work.
- Recovery: Recovery to 130 bpm between repetitions and 120 bpm between series.
- Sets or repetitions: 3 x 3 x 2 min.
- Intensity: Individual 90% movement and shot rate.
- Session duration: 18 min nominal work plus recovery.
- Frequency: One test protocol.
- Program length: Acute comparison over two weeks.
- Progression: None.
- Intermittent tennis interval training.
- Modality: Tennis cross-court forehand/backhand drill.
- Work intervals: 20 s, 20 s, 15 s, 15 s work segments within each 2 min repetition.
- Recovery: 20 s, 15 s, and 15 s within-repetition rests; recovery to 130 bpm between reps and 120 bpm between series.
- Sets or repetitions: 3 x 3 x 2 min.
- Intensity: Individual 90% movement and shot rate during work segments.
- Session duration: 18 min nominal repetition time plus recovery.
- Frequency: One test protocol.
- Program length: Acute comparison over two weeks.
- Progression: None.

## Outcomes

### Intensity
Status: no clear change
HR, lactate, and Borg RPE were high and not significantly different between HIIT and IIT.

Average HR 90.65% max in HIIT and 88.76% in IIT; final lactate 8.00 vs 8.20 mmol/L; Borg 16.33 vs 16.6.

### Shots
Status: mixed
Absolute shot count was higher in HIIT early but fell by the third series; IIT was more stable and higher relative to real work time.

HIIT > IIT in series 1 p=0.009 and series 2 p=0.056; not significant in series 3.

### Errors
Status: improved
IIT produced fewer errors than continuous HIIT across the series.

Errors lower in IIT with reported p values including series comparisons p=0.035, p=0.010, and p=0.001.

### Fatigue
Status: mixed
Continuous HIIT showed increasing errors and declining shots, while IIT maintained shot and error stability.

HIIT errors increased from series 1 to 3, p=0.03.

## Practical Insights

- When skill quality matters, inserting short rests within hard intervals can reduce errors without lowering physiological intensity.
- Shot or movement-quality metrics can reveal fatigue effects that HR, lactate, and RPE alone miss.

## Limitations

- Small sample
- Male tennis players only
- Fixed protocol order
- Acute protocol comparison only

## Safety And Adherence

- No adverse events or injuries were reported.
- Participants were healthy and supervised during tennis-specific drills.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/29021912/) (pubmed)
- [DOI](https://doi.org/10.1136/bmjsem-2017-000250) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5633734/) (full text)

## Agent Guidance

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