# Research into the Health Benefits of Sprint Interval Training Should Focus on Protocols with Fewer and Shorter Sprints

PMID: 28391489
Journal: Sports Medicine (Auckland, N.Z.)
Published: 2017 Dec
Authors: Vollaard NBJ, Metcalfe RS

## Question

Should research on sprint interval training shift from classic 4-6 x 30-second Wingate protocols toward fewer and shorter sprint protocols?

## Summary

This current-opinion review argues that classic sprint interval training using four to six 30-second all-out Wingate sprints is not clearly justified as optimal, is demanding, and may be less time-efficient than claimed. The authors recommend more research on fewer and shorter sprints, especially reduced-exertion HIIT protocols using brief 20-second sprints.

## Population

- No primary sample; narrative review of SIT and REHIT literature.
- Fitness level: Varied across cited studies
- Health status: Varied across cited studies

## Methodology

- Current opinion narrative review
- Narrative synthesis of SIT and REHIT studies

## Protocol

- Reviewed SIT/REHIT protocols.
- Modality: Primarily cycle sprinting.
- Work intervals: 20-30 seconds.
- Recovery: Varied; classic protocols often 4 minutes.
- Sets or repetitions: 2-6 sprints.
- Intensity: All-out or supramaximal.
- Session duration: About 10-30 minutes.
- Frequency: Often 3 times/week in cited studies.
- Program length: Varied.
- Progression: Varied.

## Outcomes

### VO2max
Status: improved
Shorter/fewer sprint protocols often improved VO2max in cited studies.

Narrative examples included about 7%-19% increases.

### Insulin sensitivity
Status: mixed
REHIT glucose and insulin-sensitivity results were inconsistent.

### Tolerability
Status: mixed
Classic SIT is fatiguing; shorter REHIT may be more tolerable.

## Practical Insights

- Classic 4-6 x 30-second Wingate SIT should not be treated as the only evidence-based sprint format.
- Very short protocols may be more practical when the goal is user adherence and low time burden.

## Limitations

- Narrative current-opinion article, not a systematic review.
- Safety and adherence conclusions are based on limited data.
- Many cited studies were small and heterogeneous.

## Safety And Adherence

- No primary adverse-event dataset was collected in this article.
- The authors reported no adverse events during one 8-week REHIT intervention in 16 overweight/obese prehypertensive type 2 diabetes patients, but explicitly cautioned that this does not prove safety.
- The review discusses concerns that classic SIT may be unsafe, impractical, or intolerable, but states that evidence for poor medium- or long-term adherence is lacking.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/28391489/) (pubmed)
- [DOI](https://doi.org/10.1007/s40279-017-0727-x) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5684281/) (full text)

## Agent Guidance

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