# Speed- and Circuit-Based High-Intensity Interval Training on Recovery Oxygen Consumption

PMID: 29170696
Journal: International journal of exercise science
Published: 2017
Authors: Schleppenbach LN, Ezer AB, Gronemus SA, Widenski KR, Braun SI, Janot JM

## Question

Do speed-based and circuit-based HIIT sessions differ in exercise oxygen cost, recovery oxygen consumption, and estimated caloric expenditure in regular exercisers and sedentary adults?

## Summary

In a randomized acute crossover comparison, speed interval training on a self-propelled treadmill burned more calories during the exercise bout than a bodyweight-style circuit, but recovery oxygen consumption over 30 minutes was similar. Sedentary participants reported discomfort with the self-propelled treadmill.

## Population

- Young adult regular exercisers and sedentary participants from a university campus.
- Sample size: 26
- Age: 18-30 years
- Sex: Men and women
- Fitness level: Regular exercisers and sedentary
- Health status: Apparently healthy by PAR-Q

## Methodology

- Randomized acute crossover modality comparison
- Two acute HIIT sessions separated by at least 72 hours
- University exercise laboratory
- Randomized and controlled study design.

## Protocol

- Speed interval training.
- Modality: Self-propelled treadmill running.
- Work intervals: 30 seconds.
- Recovery: 30 seconds active walking.
- Sets or repetitions: 10 bouts.
- Intensity: Target >=85% HRR; highest HRR 96.7 +/- 6.44%.
- Session duration: 15 minutes including warm-up; recovery measured for 30 minutes.
- Frequency: Single acute session.
- Program length: One session.
- Progression: None.
- Circuit training.
- Modality: Aerobic bodyweight circuit.
- Work intervals: 30 seconds.
- Recovery: 30 seconds active rest.
- Sets or repetitions: 10 bouts.
- Intensity: Target >=85% HRR; highest HRR 93.31 +/- 5.95%.
- Session duration: 15 minutes including warm-up; recovery measured for 30 minutes.
- Frequency: Single acute session.
- Program length: One session.
- Progression: None.

## Outcomes

### Exercise VO2
Status: improved
SIT elicited higher oxygen consumption during exercise than CT.

F=8.15, p=0.010.

### Recovery VO2
Status: no clear change
Recovery oxygen consumption was similar between SIT and CT and between exercise-status groups.

Modality p=0.592; exercise status p=0.885.

### Calories
Status: mixed
SIT had higher during-exercise estimated calories, but post-exercise calories did not differ.

Exercise calories p=0.010; post-exercise no modality/group effects.

## Practical Insights

- A 10 x 30/30 bodyweight circuit may produce similar 30-minute recovery oxygen cost to speed intervals.
- Running speed intervals may increase in-session oxygen cost but can be less comfortable for sedentary users.

## Limitations

- Acute-only study.
- Young campus sample.
- Calories estimated from VO2.
- Some participants could not complete or had unusable data.

## Safety And Adherence

- No adverse events or injuries were reported.
- PAR-Q screening, HR/RPE monitoring, familiarization, and qualified supervision were used; sedentary participants reported discomfort with the self-propelled treadmill.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/29170696/) (pubmed)
- [DOI](https://doi.org/10.70252/CAZV3381) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5685083/) (full text)

## Agent Guidance

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