Sprint Interval Training for Endurance Performance

Overseen By Jenna Gillen Assistant Professor, PhD

Age: 18 - 65

Sex: Female

Trial Phase: Academic

Sponsor: University of Toronto

Must not be taking: Oral contraceptives, Corticosteroids, NSAIDs, others

Disqualifiers: PCOS, Endometriosis, Cardiovascular, Metabolic, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 6

Duration: 2 weeks

24 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

Sprint interval training improves endurance performance and induces metabolic adaptations in muscle. Most research demonstrating these responses has been conducted in males, with limited studies evaluating changes to endurance performance and skeletal muscle oxidative capacity in females. Moreover, it is currently unknown if training in specific phases of the menstrual cycle influences adaptations to training. Thus, the purpose of the present study is to compare adaptations to 2 weeks of sprint interval training performed in the follicular vs. luteal phase of the menstrual cycle in healthy, eumenorrheic women.

Will I have to stop taking my current medications?

Yes, you will need to stop taking medications that affect blood glucose, lipid metabolism, or substrate metabolism, such as corticosteroids or NSAIDs, to participate in this trial.

Is sprint interval training generally safe for humans?

Sprint interval training (SIT) is generally well-tolerated and may offer health benefits, especially in older adults, although more research is needed to fully understand its safety in different populations. ^{1 2 3 4 5}

How does the treatment Sprint Interval Training differ from other treatments for endurance performance?

Sprint Interval Training (SIT) is unique because it involves short, intense bursts of exercise followed by rest, which can improve both aerobic and anaerobic performance with less time commitment compared to traditional endurance training. This makes it a time-efficient option for enhancing endurance and strength, especially for those with limited time for exercise. ^{6 7 8 9 10}

What data supports the effectiveness of the treatment Sprint Interval Training for endurance performance?

Research shows that Sprint Interval Training (SIT) can improve physical performance, including endurance, by a moderate amount in a short time. Studies found that SIT can enhance running performance and endurance adaptations, especially when combined with active recovery, making it a time-efficient alternative to traditional endurance training. ^{6 11 12 13 14}

Are You a Good Fit for This Trial?

This trial is for healthy, active women with a consistent menstrual cycle of 27-35 days and minimal variability. They should be non-smokers, engage in regular exercise (2-4 times per week), have a BMI of 18-27 kg/m2, and show evidence of ovulation. Women who don't meet these physical activity levels or menstrual cycle criteria cannot participate.

Inclusion Criteria

VO2peak of 'good' or above based on American College of Sport Medicine (ACSM) normative values (greater than 35.0ml/kg/min)

Weight stable (within ± 2kg for at least 6 months)

Non-smoker

Exclusion Criteria

Pregnant or post-partum in the last 12 months, lactating or breast feeding within 3 months of the start of study, or menopausal

I have been diagnosed with a heart or metabolic disease, or have abnormal hormone levels or PCOS.

I am currently using or have used oral contraceptives in the last 3 months.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants perform 6 sessions of sprint interval training over 2 weeks in either the Follicular Phase or Luteal Phase of their menstrual cycle

2 weeks

6 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Sprint Interval Training

Trial Overview The study is testing how sprint interval training affects endurance and muscle metabolism in women during different phases of their menstrual cycle. It compares the effects when training is done in either the follicular or luteal phase over two weeks.

How Is the Trial Designed?

Group I: Luteal Phase Training Experimental Treatment 1 Intervention

Exercise training in the luteal phase (\~days 15-28) of the participant's menstrual cycle

Group II: Follicular Phase Training Active Control 1 Intervention

Exercise training in the follicular phase (\~days 1-14) of the participant's menstrual cycle

Who Is Running the Clinical Trial?

University of Toronto

Lead Sponsor

Trials

739

Recruited

1,125,000+

Published Research Related to This Trial

A scoping review of 69 studies on high-intensity interval training (HIIT) in older adults found that HIIT protocols are generally well-tolerated and can provide significant health benefits, particularly in improving cardiorespiratory fitness.

Most research has focused on healthy older adults, highlighting a need for larger studies and more investigation into HIIT's effects on older adults with various health conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

High-Intensity Interval Training in Older Adults: a Scoping Review. Marriott, CFS., Petrella, AFM., Marriott, ECS., et al.[2021]

Citations

1. United States pubmed.ncbi.nlm.nih.gov

Six Sessions of Sprint Interval Training Improves Running Performance in Trained Athletes. [2022]

2. Germany pubmed.ncbi.nlm.nih.gov

Reducing the volume of sprint interval training does not diminish maximal and submaximal performance gains in healthy men. [2022]

3. United States pubmed.ncbi.nlm.nih.gov

Active Recovery Induces Greater Endurance Adaptations When Performing Sprint Interval Training. [2020]

4. United States pubmed.ncbi.nlm.nih.gov

The Effects of Sprint Interval Training on Physical Performance: A Systematic Review and Meta-Analysis. [2023]

5. England pubmed.ncbi.nlm.nih.gov

Endurance and sprint benefits of high-intensity and supramaximal interval training. [2013]

6. Switzerland pubmed.ncbi.nlm.nih.gov

High-Intensity Interval Training in Older Adults: a Scoping Review. [2021]

7. New Zealand pubmed.ncbi.nlm.nih.gov

Sprint interval training effects on aerobic capacity: a systematic review and meta-analysis. [2022]

8. China pubmed.ncbi.nlm.nih.gov

Risk of bias and reporting practices in studies comparing VO2max responses to sprint interval vs. continuous training: A systematic review and meta-analysis. [2022]

9. Switzerland pubmed.ncbi.nlm.nih.gov

The Dose Response for Sprint Interval Training Interventions May Affect the Time Course of Aerobic Training Adaptations. [2020]

10. Italy pubmed.ncbi.nlm.nih.gov

Overnight fasting compromises exercise intensity and volume during sprint interval training but improves high-intensity aerobic endurance. [2019]

11. Canada pubmed.ncbi.nlm.nih.gov

Modified sprint interval training protocols: physiological and psychological responses to 4 weeks of training. [2018]

12. Germany pubmed.ncbi.nlm.nih.gov

10 or 30-s sprint interval training bouts enhance both aerobic and anaerobic performance. [2022]

13. Italy pubmed.ncbi.nlm.nih.gov

Effect of sprint interval training load on maximal oxygen uptake in trained men. [2023]

14. Turkey pubmed.ncbi.nlm.nih.gov

A practical model of low-volume high-intensity interval training induces performance and metabolic adaptations that resemble 'all-out' sprint interval training. [2021]