HealthyNCT06744517
Influence of Menstrual Cycle Phase on Adaptations to Sprint Interval Training
A study testing Sprint Interval Training in people with Healthy, run by University of Toronto at 1 site in Canada.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 35 years
- Conditions the study is for
- Healthy
- What is being tested?
- Sprint Interval Training
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 36 participants
- Where
- 1 siteCanada
- Study dates
- 1 Jan 2025to 30 Jul 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 35 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Participating in 150 min of moderate-vigorous physical activity/week
- VO2peak of 'good' or above based on American College of Sport Medicine (ACSM) normative values (greater than 35.0ml/kg/min for females and greater than 39ml/kg/min for males)
- Body mass index (BMI) between 18-27 kg/m2
- Performing 2-4 structured exercise sessions/week.
- Weight stable (within ± 2kg for at least 6 months)
- Non-smoker
Show all 11Show fewer
- Females only:
- Menstrual cycle length of 27-35 days
- Minimal menstrual cycle length variability (less than 3 days)
- Ovulating monthly evidenced by a positive urinary luteinizing hormone surge
- Blood progesterone concentration greater than 16 nmol/L.
Who cannot join
- Hormonal contraceptive use within the last 3 months
- Polycystic ovarian syndrome (PCOS) or endometriosis
- Failure to meet MC verification criteria.
- Diagnosed with cardiovascular or metabolic disease, hyper- or hypogonadism, and/or PCOS
- The use of medication for managing blood glucose or lipid metabolism
- Current use of oral contraceptives or use within the last 3 months
Show all 12Show fewer
- Irregular menstrual cycles (<27 days or >35 days)
- Pregnant or post-partum in the last 12 months, lactating or breast feeding within 3 months of the start of study, or menopausal
- Recreational smoking tobacco
- Inability to perform the study exercise protocols or follow the pre-trial dietary or physical activity controls
- Taking medications affecting substrate metabolism (corticosteroids or nSAIDs)
- Actively engaging in a low-carbohydrate diet (e.g., ketogenic, Atkins)
Trial locations and contacts
1 site in 1 country.
Canada1 site
Goldring Centre for High Performance Sport
Toronto, Ontario, M5S 2C9
About this study
Official title: Influence of Menstrual Cycle Phase on Metabolic and Performance Adaptations to Sprint Interval Training
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. We will also determine how these responses differ from males.
Read the detailed description
The primary purpose of the present study is to determine if menstrual cycle phase influences adaptations to 2 weeks of sprint interval training. We will also determine if these responses differ from males. Female participants will be randomized to perform 6 sessions of sprint interval training over 2 weeks in either the Follicular Phase or Luteal Phase of their individual menstrual cycle. Blood and urine sampling will be used to confirm menstrual cycle phases. Training will involve 4-6 x 30-second Wingate sprints with 4 minutes of rest in between (~14-28 min per session). Before and after the training intervention, investigators will measure participant's aerobic and anaerobic performance, cardiorespiratory fitness and skeletal muscle outcomes. Performance and fitness measures are performed on on a stationary bike, and muscle outcomes are measured by taking a small amount of muscle from the vastus lateralis (thigh) muscle.
This study will advance knowledge on how the menstrual cycle and sex influences adaptations to training.
- Conditions
- Healthy
- Being tested
- Sprint Interval Training
- Keywords
- exercise, women
- Medical subject headings
- Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Sprint Interval TrainingOther
6 sessions of sprint interval training over 2 weeks. Each session involves 4-6 x 30 second Wingate sprints with 4 minutes of recovery in between on a stationary bike
| Study group | Role | What they receive |
|---|---|---|
| Follicular Phase Training | Active comparator | Exercise training in the follicular phase (~days 1-14) of the participant's menstrual cycle Receives: Other: Sprint Interval Training |
| Luteal Phase Training | Experimental | Exercise training in the luteal phase (~days 15-28) of the participant's menstrual cycle Receives: Other: Sprint Interval Training |
| Males | Active comparator | Exercise training in males Receives: Other: Sprint Interval Training |
What is being measured
The primary outcome is the main question the study is designed to answer.
Endurance performance
Time to completion and average power output during a 250kJ time trial
Measured: Before and after 2 weeks of exercise training
Secondary outcomes (12)
Skeletal muscle mitochondrial content
Measured via Western blotting
Measured: Before and after 2 weeks of exercise training
Skeletal muscle mitochondrial enzyme activity
Measured via enzyme activity assays
Measured: Before and after 2 weeks of exercise training
Skeletal muscle capillarization
Measured via immunofluorescence
Measured: Before and after 2 weeks of exercise training
Skeletal muscle lipid content
Measured via immunofluorescence
Measured: Before and after 2 weeks of exercise training
Skeletal muscle protein synthesis
Measured via the incorporation of a stable isotope tracer during the 2 weeks of training
Measured: Before and after 2 weeks of exercise training
Cardiorespiratory fitness
Measured via a maximal exercise test on a cycle ergometer
Measured: Before and after 2 weeks of exercise training
Anaerobic exercise performance
Power output during a Wingate anaerobic test
Measured: Before and after 2 weeks of exercise training
Skeletal muscle carbohydrate and fat metabolism
measured via Western blotting
Measured: Before and after training 2 weeks of training
Fasting Insulin Resistance
Measured via homoestatic model assessment (HOMA-IR)
Measured: Before and after 2 weeks of training
Fasting plasma insulin
measured via ELISA
Measured: Before and after 2 weeks of training
Fasting plasma glucose
measured via blood assay
Measured: Before and after 2 weeks of training
Sex hormones (estrogen, progesterone, testosterone)
measured via plasma assay
Measured: Before and after 2 weeks of training
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Dec 2024
- Study start1 Jan 2025
- Primary completion30 Jul 2026
- Study completion30 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by University of TorontoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 36 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Toronto
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Jenna Gillen, University of Toronto
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06744517
- Sponsor's protocol ID
- HSREB50581
- Status last verified
- Apr 2026
- First submitted
- 16 Dec 2024
- Last updated
- 12 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 12 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Influence of Menstrual Cycle Phase on Metabolic and Performance Adaptations to Sprint Interval Training
- ClinicalTrials.gov ID
- NCT06744517
- Acronym / sponsor ID
- HSREB50581
- Conditions
- Healthy
- Keywords
- exercise, women
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 36 participants (actual)
- Lead sponsor
- University of TorontoUniversity, hospital or other
- Study start
- 1 Jan 2025 (actual)
- Primary completion
- 30 Jul 2026 (actual)
- Study completion
- 30 Jul 2026 (actual)
- First posted
- 20 Dec 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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. We will also determine how these responses differ from males.
Detailed description
The primary purpose of the present study is to determine if menstrual cycle phase influences adaptations to 2 weeks of sprint interval training. We will also determine if these responses differ from males. Female participants will be randomized to perform 6 sessions of sprint interval training over 2 weeks in either the Follicular Phase or Luteal Phase of their individual menstrual cycle. Blood and urine sampling will be used to confirm menstrual cycle phases. Training will involve 4-6 x 30-second Wingate sprints with 4 minutes of rest in between (~14-28 min per session). Before and after the training intervention, investigators will measure participant's aerobic and anaerobic performance, cardiorespiratory fitness and skeletal muscle outcomes. Performance and fitness measures are performed on on a stationary bike, and muscle outcomes are measured by taking a small amount of muscle from the vastus lateralis (thigh) muscle.
This study will advance knowledge on how the menstrual cycle and sex influences adaptations to training.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Follicular Phase Training | Active comparator | Other: Sprint Interval TrainingExercise training in the follicular phase (~days 1-14) of the participant's menstrual cycle |
| Luteal Phase Training | Experimental | Other: Sprint Interval TrainingExercise training in the luteal phase (~days 15-28) of the participant's menstrual cycle |
| Males | Active comparator | Other: Sprint Interval TrainingExercise training in males |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (11 listed)
- Participating in 150 min of moderate-vigorous physical activity/week
- VO2peak of 'good' or above based on American College of Sport Medicine (ACSM) normative values (greater than 35.0ml/kg/min for females and greater than 39ml/kg/min for males)
- Body mass index (BMI) between 18-27 kg/m2
- Performing 2-4 structured exercise sessions/week.
- Weight stable (within ± 2kg for at least 6 months)
Key exclusion criteria (12 listed)
- Hormonal contraceptive use within the last 3 months
- Polycystic ovarian syndrome (PCOS) or endometriosis
- Failure to meet MC verification criteria.
- Diagnosed with cardiovascular or metabolic disease, hyper- or hypogonadism, and/or PCOS
- The use of medication for managing blood glucose or lipid metabolism
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Sprint Interval Training6 sessions of sprint interval training over 2 weeks. Each session involves 4-6 x 30 second Wingate sprints with 4 minutes of recovery in between on a stationary bike | Other | Follicular Phase Training, Luteal Phase Training, Males |
Primary outcome
Endurance performance
Time frame: Before and after 2 weeks of exercise training
Time to completion and average power output during a 250kJ time trial
12 secondary outcomes
Skeletal muscle mitochondrial content
Time frame: Before and after 2 weeks of exercise training
Skeletal muscle mitochondrial enzyme activity
Time frame: Before and after 2 weeks of exercise training
Skeletal muscle capillarization
Time frame: Before and after 2 weeks of exercise training
Skeletal muscle lipid content
Time frame: Before and after 2 weeks of exercise training
Skeletal muscle protein synthesis
Time frame: Before and after 2 weeks of exercise training
Cardiorespiratory fitness
Time frame: Before and after 2 weeks of exercise training
Anaerobic exercise performance
Time frame: Before and after 2 weeks of exercise training
Skeletal muscle carbohydrate and fat metabolism
Time frame: Before and after training 2 weeks of training
Fasting Insulin Resistance
Time frame: Before and after 2 weeks of training
Fasting plasma insulin
Time frame: Before and after 2 weeks of training
Fasting plasma glucose
Time frame: Before and after 2 weeks of training
Sex hormones (estrogen, progesterone, testosterone)
Time frame: Before and after 2 weeks of training
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Aug 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Sprint Interval Training in people with Healthy, run by University of Toronto at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 11 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Endurance performance (time frame: Before and after 2 weeks of exercise training). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Aug 2026.