Physical FitnessNCT07915349
High-Intensity Interval Training Versus Moderate-Intensity Continuous Training in Physically Trained Adults
A study testing High-Intensity Interval Training and Moderate-Intensity Continuous Training in people with Physical Fitness and Cardiorespiratory Fitness, run by Agri Ibrahim Cecen University at 1 site in Turkey (Türkiye).
Trial summary
This randomized controlled trial compared the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on physiological and functional outcomes in physically trained adults aged 18-35 years. A total of 46 participants were assigned to two exercise groups. Read more about this study
- Who is it for?
- Ages 18 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Physical Fitness, Cardiorespiratory Fitness
- What is being tested?
- High-Intensity Interval Training and Moderate-Intensity Continuous Training
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 46 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Dec 2025to 1 Oct 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
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy men and women aged 18-35 years.
- Regular participation in physical exercise at least three days per week.
- At least two years of previous exercise training experience.
- Estimated maximal oxygen uptake (VO2max) of at least 35 mL/kg/min.
- Ability to safely perform maximal cycle-ergometer testing.
- Provision of written informed consent.
Who cannot join
- Clinically significant cardiovascular, respiratory, metabolic, neurological, or vestibular disorders.
- Major musculoskeletal injury or surgery within the previous six months.
- Any medical or physical condition preventing safe participation in exercise or balance assessments.
- Active smoking.
- Problematic alcohol consumption.
- Use of prohibited performance-enhancing substances.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Effects of High-Intensity Interval Training Versus Moderate-Intensity Continuous Training on Physiological and Functional Outcomes: A Randomized Controlled Trial
This randomized controlled trial compared the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on physiological and functional outcomes in physically trained adults aged 18-35 years. A total of 46 participants were assigned to two exercise groups. Both groups followed an eight-week supervised cycling program, with three 30-minute sessions per week. Assessments were conducted at baseline, week 4, and week 8. The study evaluated estimated aerobic capacity, anaerobic performance, postural balance, pulmonary function, and heart rate variability to determine how these outcomes respond to different exercise intensities.
Read the detailed description
This single-center, two-arm, parallel-group randomized controlled trial was conducted at Bursa Uludağ University, Türkiye. The study included 46 physically trained adults aged 18-35 years, allocated to either HIIT (n=23) or MICT (n=23).
Participants performed supervised cycle-ergometer exercise three times weekly for eight weeks. The HIIT group performed repeated high-intensity cycling intervals interspersed with active recovery, whereas the MICT group performed continuous cycling at moderate intensity. Both interventions involved 30 minutes of prescribed cycling per session.
Outcome assessments were conducted at baseline, week 4, and week 8. Aerobic capacity was estimated using an incremental cycle-ergometer test. Anaerobic performance was evaluated using the Wingate test. Additional assessments included static and dynamic balance, functional mobility, spirometry, and resting heart rate variability.
The study was designed to compare the physiological and functional adaptations associated with these two exercise-training approaches in physically trained young adults.
- Conditions
- Physical Fitness, Cardiorespiratory Fitness
- Being tested
- High-Intensity Interval Training, Moderate-Intensity Continuous Training
- Keywords
- High-Intensity Interval Training (HIIT), Moderate-Intensity Continuous Training (MICT), Aerobic Capacity, Estimated VO2max, Anaerobic Performance, Heart Rate Variability, Pulmonary Function, Postural Balance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
High-Intensity Interval TrainingBehavioural
Also called HIIT
An eight-week supervised cycle-ergometer training program consisting of 24 planned sessions. Each session involved 30 minutes of cycling with high-intensity work intervals targeting approximately 85-95% of maximum heart rate, interspersed with active recovery. Work/recovery intervals progressed from 20/40 seconds in weeks 1-2 to 45/15 seconds in weeks 7-8.
Moderate-Intensity Continuous TrainingBehavioural
An eight-week supervised cycle-ergometer training program consisting of 24 planned sessions. Participants performed uninterrupted continuous cycling at 60-70% of maximum heart rate for 30 minutes per session, three times weekly.
| Study group | Role | What they receive |
|---|---|---|
| High-Intensity Interval Training (HIIT) | Experimental | Participants (n=23) were assigned to supervised high-intensity interval training consisting of 30-minute cycling sessions, three times weekly for eight weeks, with high-intensity exercise intervals alternating with active recovery periods. Receives: Behavioral: High-Intensity Interval Training |
| Moderate-Intensity Continuous Training (MICT) | Active comparator | Participants (n=23) were assigned to supervised moderate-intensity continuous cycling at 60-70% of maximum heart rate for 30 minutes per session, three times weekly for eight weeks. Receives: Behavioral: Moderate-Intensity Continuous Training |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from Baseline in Estimated Maximal Oxygen Uptake (VO2max)
Estimated VO2max was determined using an incremental cycle-ergometer test and the FRIEND equation based on peak work rate and body mass. Values were expressed in mL/kg/min. Changes from baseline were assessed at weeks 4 and 8.
Measured: Baseline, Week 4, and Week 8
Secondary outcomes (18)
Change from Baseline in Wingate Peak Power
Peak anaerobic power was assessed during the 30-second Wingate cycle-ergometer test. The highest power output during a 5-second interval was recorded and normalized to body mass (W/kg).
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Wingate Mean Power
Mean anaerobic power was assessed during the 30-second Wingate cycle-ergometer test. Average power output was normalized to body mass and expressed in W/kg.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Wingate Fatigue Index
The fatigue index was calculated during the 30-second Wingate test as the percentage decline from peak to minimum power output. Values were expressed as percentages (%).
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Wingate Total Work
Total mechanical work performed during the 30-second Wingate cycle-ergometer test was normalized to body mass and expressed in J/kg.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Single-Leg Stance Duration
Static postural balance was assessed by measuring the duration participants maintained a single-leg stance on a firm surface. Performance was expressed in seconds.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Balance Error Scoring System (BESS) Total Score
Postural stability was assessed using the Balance Error Scoring System across six standing conditions on firm and foam surfaces. The total number of balance errors was recorded, with lower scores indicating better postural control.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Y-Balance Test Composite Score
Dynamic balance was assessed using the Y-Balance Test in anterior, posteromedial, and posterolateral directions. Reach distances were normalized to lower-limb length and expressed as a composite percentage score (%).
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Timed Up and Go Test Performance
Functional mobility was evaluated using the Timed Up and Go test. Participants stood from a chair, walked 3 meters, turned, returned, and sat down. Completion time was recorded in seconds, with shorter times indicating better performance.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Forced Vital Capacity (FVC)
Forced vital capacity (FVC) was measured by spirometry using the COSMED MicroQuark system and expressed in liters (L). The change from baseline was assessed at weeks 4 and 8.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Forced Expiratory Volume in One Second (FEV1)
Forced expiratory volume in one second (FEV1) was measured using the COSMED MicroQuark spirometer and expressed in liters (L). The change from baseline was assessed at weeks 4 and 8.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in FEV1/FVC Ratio
The ratio of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) was calculated and expressed as a percentage (%). The change from baseline was assessed at weeks 4 and 8.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Forced Mid-Expiratory Flow (FEF25-75)
Forced mid-expiratory flow between 25% and 75% of forced vital capacity (FEF25-75) was measured using the COSMED MicroQuark spirometer and expressed in liters per second (L/s). The change from baseline was assessed at weeks 4 and 8.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Peak Expiratory Flow (PEF)
Peak expiratory flow (PEF) was measured during forced expiration using the COSMED MicroQuark spirometer and expressed in liters per second (L/s). The change from baseline was assessed at weeks 4 and 8.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Maximal Voluntary Ventilation (MVV)
Maximal voluntary ventilation (MVV) was measured using the COSMED MicroQuark spirometry system and expressed in liters per minute (L/min). The change from baseline was assessed at weeks 4 and 8.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in Natural Log-Transformed RMSSD (lnRMSSD)
The natural log-transformed root mean square of successive differences between normal heartbeats (lnRMSSD) was derived from resting cardiac interbeat intervals recorded using a Polar H10 chest strap and analyzed with Kubios HRV Premium software. Values were expressed on the natural-log scale (ln[ms]). The change from baseline was assessed at weeks 4 and 8.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in SDNN
The standard deviation of normal-to-normal heart-beat intervals (SDNN) was calculated from resting cardiac interbeat interval recordings acquired using a Polar H10 chest strap and analyzed with Kubios HRV Premium software. Values were expressed in milliseconds (ms). The change from baseline was assessed at weeks 4 and 8.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in LF/HF Power Ratio
The ratio of low-frequency to high-frequency heart rate variability power (LF/HF) was derived from resting recordings using a Polar H10 chest strap and Kubios HRV Premium software. Values were expressed as a unitless ratio. The change from baseline was assessed at weeks 4 and 8.
Measured: Baseline, Week 4, and Week 8
Change from Baseline in High-Frequency HRV Power (HF)
High-frequency (HF) heart rate variability power was derived from resting recordings using a Polar H10 chest strap and Kubios HRV Premium software. Values were expressed in milliseconds squared (ms²). The change from baseline was assessed at weeks 4 and 8.
Measured: Baseline, Week 4, and Week 8
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Nov 2026
- Study start1 Dec 2025
- Primary completion1 Oct 2026
- Study completion1 Oct 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Physical FitnessStudies of the same condition, open and under way.
- 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
- Model description
- This study employed a two-arm, parallel-group randomized controlled design. A total of 46 physically trained adults were allocated to either high-intensity interval training (HIIT; n=23) or moderate-intensity continuous training (MICT; n=23). Both groups completed an eight-week supervised exercise program, with assessments at baseline, week 4, and week 8.
- Masking
- None (open label)
- Enrolment
- 46 participants (actual)
Sponsor and investigators
- Lead sponsor
- Agri Ibrahim Cecen University
- Sponsor type
- University, hospital or other
- Collaborators
- Health Institute of Türkiye (TÜSEB)
- Responsible party
- Principal investigator, Dursun Alper YILMAZ, Agri Ibrahim Cecen University
- Investigators
- Fadıl Özyener, Study director, Uludag University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07915349
- Sponsor's protocol ID
- HIITMICT-2025-01
- Status last verified
- Oct 2026
- First submitted
- 24 Oct 2026
- Last updated
- 4 Nov 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: There is currently no plan to share individual participant data with external researchers. Study findings will be reported in aggregate form.
Study at a glance
From the registry record, last updated by the sponsor on 4 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of High-Intensity Interval Training Versus Moderate-Intensity Continuous Training on Physiological and Functional Outcomes: A Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07915349
- Acronym / sponsor ID
- HIITMICT-2025-01
- Conditions
- Physical Fitness, Cardiorespiratory Fitness
- Keywords
- High-Intensity Interval Training (HIIT), Moderate-Intensity Continuous Training (MICT), Aerobic Capacity, Estimated VO2max, Anaerobic Performance, Heart Rate Variability, Pulmonary Function, Postural Balance
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 46 participants (actual)
- Lead sponsor
- Agri Ibrahim Cecen UniversityUniversity, hospital or other
- Collaborators
- Health Institute of Türkiye (TÜSEB)
- Study start
- 1 Dec 2025 (actual)
- Primary completion
- 1 Oct 2026 (actual)
- Study completion
- 1 Oct 2026 (actual)
- First posted
- 4 Nov 2026 (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.
This randomized controlled trial compared the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on physiological and functional outcomes in physically trained adults aged 18-35 years. A total of 46 participants were assigned to two exercise groups. Both groups followed an eight-week supervised cycling program, with three 30-minute sessions per week. Assessments were conducted at baseline, week 4, and week 8. The study evaluated estimated aerobic capacity, anaerobic performance, postural balance, pulmonary function, and heart rate variability to determine how these outcomes respond to different exercise intensities.
Detailed description
This single-center, two-arm, parallel-group randomized controlled trial was conducted at Bursa Uludağ University, Türkiye. The study included 46 physically trained adults aged 18-35 years, allocated to either HIIT (n=23) or MICT (n=23).
Participants performed supervised cycle-ergometer exercise three times weekly for eight weeks. The HIIT group performed repeated high-intensity cycling intervals interspersed with active recovery, whereas the MICT group performed continuous cycling at moderate intensity. Both interventions involved 30 minutes of prescribed cycling per session.
Outcome assessments were conducted at baseline, week 4, and week 8. Aerobic capacity was estimated using an incremental cycle-ergometer test. Anaerobic performance was evaluated using the Wingate test. Additional assessments included static and dynamic balance, functional mobility, spirometry, and resting heart rate variability.
The study was designed to compare the physiological and functional adaptations associated with these two exercise-training approaches in physically trained young adults.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- This study employed a two-arm, parallel-group randomized controlled design. A total of 46 physically trained adults were allocated to either high-intensity interval training (HIIT; n=23) or moderate-intensity continuous training (MICT; n=23). Both groups completed an eight-week supervised exercise program, with assessments at baseline, week 4, and week 8.
| Arm | Type | Receives |
|---|---|---|
| High-Intensity Interval Training (HIIT) | Experimental | Behavioral: High-Intensity Interval TrainingParticipants (n=23) were assigned to supervised high-intensity interval training consisting of 30-minute cycling sessions, three times weekly for eight weeks, with high-intensity exercise intervals alternating with active recovery periods. |
| Moderate-Intensity Continuous Training (MICT) | Active comparator | Behavioral: Moderate-Intensity Continuous TrainingParticipants (n=23) were assigned to supervised moderate-intensity continuous cycling at 60-70% of maximum heart rate for 30 minutes per session, three times weekly for eight weeks. |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Healthy men and women aged 18-35 years.
- Regular participation in physical exercise at least three days per week.
- At least two years of previous exercise training experience.
- Estimated maximal oxygen uptake (VO2max) of at least 35 mL/kg/min.
- Ability to safely perform maximal cycle-ergometer testing.
Key exclusion criteria (6 listed)
- Clinically significant cardiovascular, respiratory, metabolic, neurological, or vestibular disorders.
- Major musculoskeletal injury or surgery within the previous six months.
- Any medical or physical condition preventing safe participation in exercise or balance assessments.
- Active smoking.
- Problematic alcohol consumption.
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 |
|---|---|---|
| High-Intensity Interval TrainingAlso: HIITAn eight-week supervised cycle-ergometer training program consisting of 24 planned sessions. Each session involved 30 minutes of cycling with high-intensity work intervals targeting approximately 85-95% of maximum heart rate, interspersed with active recovery. Work/recovery intervals progressed from 20/40 seconds in weeks 1-2 to 45/15 seconds in weeks 7-8. | Behavioural | High-Intensity Interval Training (HIIT) |
| Moderate-Intensity Continuous TrainingAn eight-week supervised cycle-ergometer training program consisting of 24 planned sessions. Participants performed uninterrupted continuous cycling at 60-70% of maximum heart rate for 30 minutes per session, three times weekly. | Behavioural | Moderate-Intensity Continuous Training (MICT) |
Primary outcome
Change from Baseline in Estimated Maximal Oxygen Uptake (VO2max)
Time frame: Baseline, Week 4, and Week 8
Estimated VO2max was determined using an incremental cycle-ergometer test and the FRIEND equation based on peak work rate and body mass. Values were expressed in mL/kg/min. Changes from baseline were assessed at weeks 4 and 8.
18 secondary outcomes
Change from Baseline in Wingate Peak Power
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Wingate Mean Power
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Wingate Fatigue Index
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Wingate Total Work
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Single-Leg Stance Duration
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Balance Error Scoring System (BESS) Total Score
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Y-Balance Test Composite Score
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Timed Up and Go Test Performance
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Forced Vital Capacity (FVC)
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Forced Expiratory Volume in One Second (FEV1)
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in FEV1/FVC Ratio
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Forced Mid-Expiratory Flow (FEF25-75)
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Peak Expiratory Flow (PEF)
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Maximal Voluntary Ventilation (MVV)
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in Natural Log-Transformed RMSSD (lnRMSSD)
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in SDNN
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in LF/HF Power Ratio
Time frame: Baseline, Week 4, and Week 8
Change from Baseline in High-Frequency HRV Power (HF)
Time frame: Baseline, Week 4, and Week 8
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 4 Nov 2026.
- Individual participant dataSharing planned: No. There is currently no plan to share individual participant data with external researchers. Study findings will be reported in aggregate form.
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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.
Fadıl Özyener study director
Uludag University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing High-Intensity Interval Training and Moderate-Intensity Continuous Training in people with Physical Fitness and Cardiorespiratory Fitness, run by Agri Ibrahim Cecen University at 1 site in Turkey (Türkiye).
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 6 inclusion and 6 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 4 Nov 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 Turkey (Türkiye). 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?
Change from Baseline in Estimated Maximal Oxygen Uptake (VO2max) (time frame: Baseline, Week 4, and Week 8). 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 4 Nov 2026.