# Adaptive responses of cardiorespiratory system and hormonal parameters to individualized high-intensity interval training using anaerobic power reserve in well-trained rowers

PMID: 37168222
Journal: Frontiers in Physiology
Published: 2023-04-24
Authors: Wang X, Zhao L

## Question

Does individualized HIIT using anaerobic power reserve produce different cardiorespiratory and hormonal adaptations than HIIT prescribed as 130% maximal aerobic power in well-trained rowers?

## Summary

In national-level male rowers, 6 weeks of rowing HIIT improved VO2max, 2000 m performance, maximal aerobic power, and testosterone-to-cortisol ratio in both groups. Prescribing intensity from anaerobic power reserve did not improve average outcomes more than 130% MAP, but produced more uniform cardiorespiratory and performance responses.

## Population

- National-level male rowers.
- Sample size: 20
- Age: 22 +/- 3 years
- Sex: Male only
- Fitness level: Well-trained, about 12 years rowing experience
- Health status: Medically screened athletes

## Methodology

- Randomized controlled training study
- 6 weeks
- Rowing ergometer training and laboratory testing
- Randomized and controlled study design.

## Protocol

- APR-based rowing HIIT.
- Modality: Rowing ergometer.
- Work intervals: 60 seconds.
- Recovery: 60 seconds relief, 3 minutes between sets.
- Sets or repetitions: 2 sets of 6-10 repetitions.
- Intensity: MAP + 30% anaerobic power reserve.
- Session duration: Varied by weekly repetition count.
- Frequency: 3 sessions/week.
- Program length: 6 weeks.
- Progression: 6, 6, 8, 8, 10, 10 repetitions per set over weeks 1-6.
- MAP-based rowing HIIT.
- Modality: Rowing ergometer.
- Work intervals: 60 seconds.
- Recovery: 60 seconds relief, 3 minutes between sets.
- Sets or repetitions: 2 sets of 6-10 repetitions.
- Intensity: 130% maximal aerobic power.
- Session duration: Varied by weekly repetition count.
- Frequency: 3 sessions/week.
- Program length: 6 weeks.
- Progression: Same repetition progression as APR group.

## Outcomes

### VO2max
Status: improved
Relative VO2max improved in both APR and MAP groups.

APR 55.4 to 59.1 ml/kg/min (+6.6%, p=.005); MAP 54.0 to 57.1 (+5.7%, p=.003).

### 2000 m time
Status: improved
Both groups improved 2000 m rowing time by about 1.4-1.5%.

APR 380.6 to 374.9 s, p=.006; MAP 377.6 to 372.2 s, p=.001.

### Response variability
Status: improved
APR-based prescription showed lower variability for several cardiorespiratory and performance adaptations.

Authors reported lower coefficients of variation for VO2max, VO2/HR, VE, Rf, VT1, and performance outcomes.

### Hormones
Status: improved
Testosterone and testosterone-to-cortisol ratio increased in both groups, with no clear between-group advantage.

T/C ratio increased 13.4% in APR and 15.4% in MAP; both p<.01.

## Practical Insights

- A 60:60 interval structure can improve fitness and performance in well-trained rowers.
- Intensity personalization may reduce variability, even when mean group gains are similar.
- Progressing interval count is a practical dose progression.

## Limitations

- Small sample.
- Male athlete-only population.
- Sample size was inconsistent between abstract and methods.
- Diet, sleep, and motivation were not strictly monitored.
- Rowing ergometer results may not translate to bodyweight HIIT.

## Safety And Adherence

- No adverse events were stated in the reviewed text.
- Participants were medically screened.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/37168222/) (pubmed)
- [DOI](https://doi.org/10.3389/fphys.2023.1177108) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10164958/) (full text)

## Agent Guidance

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