HRVNCT06860204
Weight Cut Stress: the Hidden Struggle Beyond Fight Day
An observational study of HRV and Psychological Adaptation, run by Erzurum Technical University at 1 site in Turkey (Türkiye).
Trial summary
This study investigated the effects of rapid weight-cutting on stress in elite kickboxers by analyzing Heart Rate Variability (HRV) and subjective stress levels using a Visual Analog Scale (VAS). Read more about this study
- Who is it for?
- Ages 16 to 35 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- HRV, Psychological Adaptation
- How many people
- 25 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 2 Nov 2024to 10 Nov 2024
- Phase
- Observational
- 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 16 to 35 years
- Men only
- Healthy volunteers accepted
- Child, Adult
Study population: The study population consisted of elite male kickboxers competing at the Senior European Kickboxing Championship in Greece. Participants were aged 18 to 35 years and had a minimum of 5 years of competitive experience at the national or international level. Athletes were divided into two groups: Weight-Cutting Group (n = 12): Athletes who lost at least 5% of their body weight within 48 hours prior to weigh-in. Control Group (n = 13): Athletes who maintained their regular training and nutrition, with no more than 2% weight fluctuation before the competition. All participants underwent heart rate variability (HRV) assessments using photoplethysmography (PPG) via Apple Watch Series 8 and subjective stress evaluations using the Visual Analog Scale (VAS) at seven time points from weigh-in morning to post-match. Participants were selected based on strict inclusion and exclusion criteria to ensure comparability between groups.
Who may be able to join
- Elite male kickboxers aged between 18 and 35 years
- Minimum 5 years of competitive experience at the national or international level
- Actively competing in the Senior European Kickboxing Championship
- For the weight-cutting group: Must have lost at least 5% of body weight within the 48 hours prior to weigh-in
Who cannot join
- Athletes who lost between 3-4% of their body weight, as they do not fit into either group
- History of cardiovascular diseases
- History of metabolic disorders
- Any medical condition that could affect HRV measurements
- Current or recent injuries (within the last 3 months) that could impair performance or stress responses
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Erzurum Technical University, Faculty of Sport Sciences
Erzurum, Erzurum, 25050
About this study
Official title: Cutting Weight, Gaining Stress: the Hidden Battle That Outweighs Fight Day Tension in Kickboxing
This study investigated the effects of rapid weight-cutting on stress in elite kickboxers by analyzing Heart Rate Variability (HRV) and subjective stress levels using a Visual Analog Scale (VAS). Data were collected across seven time points: Weigh-in Morning, Pre-Weigh-in, Post-Weigh-in, Post-Weigh-in Meal, Match Day Morning, Pre-Match, and Post-Match. Participants were divided into a weight-cutting group (n = 12), who reduced at least 5% of their body weight within 48 hours before competition, and a control group (n = 13), who maintained regular training and nutrition. HRV was measured using Apple Watch photoplethysmography under real-world conditions during the Senior European Kickboxing Championship in Greece. Results showed consistently lower RMSSD, indicating sustained physiological stress in the weight-cutting group. Subjective stress levels were also higher in this group, peaking before the weigh-in and exceeding pre-match levels. A notable decrease in subjective stress was observed immediately after the weigh-in, attributed to psychological relief rather than physical recovery. However, low RMSSD persisted on match day, indicating incomplete physiological recovery despite stabilized subjective stress. The control group demonstrated stable HRV and VAS. These findings highlight the prolonged autonomic strain of rapid weight-cutting, emphasizing the need for careful management to safeguard athlete health and performance.
Read the detailed description
Objective:
This study aims to investigate the effects of rapid weight-cutting on objective (Heart Rate Variability - HRV, measured via RMSSD) and subjective (Visual Analog Scale - VAS) stress parameters in elite kickboxers. The evaluation will occur across seven specific time points: Weigh-in Morning, Pre-Weigh-in, Post-Weigh-in, Post-Weigh-in Meal, Match Day Morning, Pre-Match, and Post-Match.
Study Design:
An observational comparative design will be employed to assess objective and subjective stress responses related to weight-cutting in elite kickboxers. The study will take place during the Senior European Kickboxing Championship in Greece, from November 2 to November 10, 2024, under real competition conditions. Two groups will be included: a weight-cutting group and a non-weight-cutting group. This design will enable comparisons between objective (RMSSD) and subjective (VAS) stress measures, as well as between athletes who reduce weight and those who do not. Data will be collected at seven key time points to capture stress variations during the weight-cutting and competition phases.
Participants:
Elite kickboxers will be selected based on specific inclusion criteria. A sample size calculation using G*Power, based on an ANOVA with repeated measures and within-between interaction, determined a minimum of 22 participants to ensure adequate statistical power. Parameters include an effect size of 0.25, an alpha level of 0.05, and a power of 0.90. Accounting for potential data loss, the study targets 25 participants, with 12 in the weight-cutting group and 13 in the non-weight-cutting group. Participants will be active male elite kickboxers, aged 18-35, with at least five years of national or international competitive experience. The weight-cutting group will consist of athletes losing at least 5% of their body weight within 48 hours before the weigh-in, while the non-weight-cutting group will include those with no weight-cutting procedures and a maximum weight loss of 2% during pre-weigh-in training. Participation will be voluntary, with athletes provided detailed information about the study's purpose, methods, and risks, and written informed consent will be obtained. Confidentiality will be ensured, and data will be used solely for research purposes. The study has been approved by the Erzurum Technical University Scientific Research and Publication Ethics Committee (Meeting No: 10, Decision No: 10, Date: 12.09.2024).
Data Collection:
Data collection will focus on objective and subjective stress parameters using HRV and VAS. Objective stress will be measured via RMSSD values, recorded with Apple Watch Series 8 devices equipped with photoplethysmography technology. Participants will wear the device in a calm, seated position for five-minute intervals to ensure reliable HRV data. Subjective stress will be assessed using the VAS, where participants rate their perceived stress on a scale. Measurements will occur at seven time points surrounding the weigh-in and competition period: Weigh-in Morning, Pre-Weigh-in, Post-Weigh-in, Post-Weigh-in Meal, Match Day Morning, Pre-Match, and Post-Match.
Data Analysis:
Data will be analyzed using SPSS version 26. Pairwise group comparisons will use Hedges' g effect size calculations, adjusted for small sample sizes, and interpreted classification (trivial < 0.2, small 0.2-0.59, moderate 0.60-1.19, large 1.20-1.99, very large 2.0-3.99, nearly perfect > 4.0). Changes across the seven time points for RMSSD and VAS will be examined with repeated measures ANOVA, including within-between interactions. Significant effects or interactions will be followed by Bonferroni-adjusted post hoc tests to control for multiple comparisons. Partial eta-squared (η²ₚ) values will be reported to evaluate practical significance. Statistical significance will be set at p < 0.05.
- Conditions
- HRV, Psychological Adaptation
- Keywords
- Rapid weight loss, weight-cutting, elite kickboxers, heart rate variability, RMSSD
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| weight-cutting group | Athletes in the weight-cutting group were defined as those who had lost at least 5% of their body weight within the 48 hours prior to weigh-in. | |
| control group | Participants in the non-weight-cutting group did not engage in any weight-cutting procedures |
What is being measured
The primary outcome is the main question the study is designed to answer.
Heart Rate Variability (HRV) - RMSSD Changes Over Time
Heart Rate Variability (HRV) was assessed using the Root Mean Square of the Successive Differences (RMSSD) to evaluate autonomic nervous system stress responses. RMSSD values were measured to determine the impact of rapid weight-cutting on physiological stress and recovery. Lower RMSSD values indicate higher physiological stress and impaired autonomic function.
Measured: Baseline (Weigh-in Morning), immediately before weigh-in, immediately after weigh-in, post-weigh-in meal, morning of match day, immediately before match, immediately after match
Secondary outcomes (1)
Subjective Stress Levels (VAS Scores) Over Time
Subjective stress levels were assessed using the Visual Analog Scale (VAS), where participants rated their perceived stress from 0 (no stress) to 10 (extreme stress). Measurements were taken to evaluate the psychological impact of rapid weight-cutting. Higher VAS scores indicate greater subjective stress.
Measured: Baseline (Weigh-in Morning), immediately before weigh-in, immediately after weigh-in, post-weigh-in meal, morning of match day, immediately before match, immediately after match
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Mar 2025
- Study start2 Nov 2024
- Primary completion10 Nov 2024
- Study completion10 Nov 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for HRVStudies 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
- Observational
- Observational model
- Other
- Time perspective
- Prospective
- Enrolment
- 25 participants (actual)
Sponsor and investigators
- Lead sponsor
- Erzurum Technical University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Salih ÇABUK, Erzurum Technical University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06860204
- Sponsor's protocol ID
- ETU-REC-2024-10
- Status last verified
- Mar 2025
- First submitted
- 25 Feb 2025
- Last updated
- 7 Mar 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: De-identified individual participant data (IPD) will be shared with researchers upon reasonable request. The following data will be available: Heart Rate Variability (HRV) data (RMSSD values) collected at seven time points Visual Analog Scale (VAS) stress scores at seven time points Basic demographic data (age, weight category, competition level) Access and Conditions: Data will be available after study publication for researchers conducting related studies in sports science, physiology, or psychology. Researchers must submit a formal request, including a study proposal, to the corresponding author (Burak Karababa, burak.karababa@erzurum.edu.tr). Access will be granted upon approval and agreement to data use terms, ensuring confidentiality and ethical research practices.
Publications
Karababa B, Ulupinar S, Gencoglu C, Asan S, Bedir D, Ince I, Cabuk S, Canyurt F, Ozbay S, Kaya K. Cutting weight, gaining stress: the hidden battle that outweighs fight day tension in kickboxing. Front Psychol. 2026 Mar 16;17:1762659. doi: 10.3389/fpsyg.2026.1762659. eCollection 2026.
PubMed 41919118
Study at a glance
From the registry record, last updated by the sponsor on 7 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Cutting Weight, Gaining Stress: the Hidden Battle That Outweighs Fight Day Tension in Kickboxing
- ClinicalTrials.gov ID
- NCT06860204
- Acronym / sponsor ID
- ETU-REC-2024-10
- Conditions
- HRV, Psychological Adaptation
- Keywords
- Rapid weight loss, weight-cutting, elite kickboxers, heart rate variability, RMSSD
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 25 participants (actual)
- Lead sponsor
- Erzurum Technical UniversityUniversity, hospital or other
- Study start
- 2 Nov 2024 (actual)
- Primary completion
- 10 Nov 2024 (actual)
- Study completion
- 10 Nov 2024 (actual)
- First posted
- 5 Mar 2025 (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 study investigated the effects of rapid weight-cutting on stress in elite kickboxers by analyzing Heart Rate Variability (HRV) and subjective stress levels using a Visual Analog Scale (VAS). Data were collected across seven time points: Weigh-in Morning, Pre-Weigh-in, Post-Weigh-in, Post-Weigh-in Meal, Match Day Morning, Pre-Match, and Post-Match. Participants were divided into a weight-cutting group (n = 12), who reduced at least 5% of their body weight within 48 hours before competition, and a control group (n = 13), who maintained regular training and nutrition. HRV was measured using Apple Watch photoplethysmography under real-world conditions during the Senior European Kickboxing Championship in Greece. Results showed consistently lower RMSSD, indicating sustained physiological stress in the weight-cutting group. Subjective stress levels were also higher in this group, peaking before the weigh-in and exceeding pre-match levels. A notable decrease in subjective stress was observed immediately after the weigh-in, attributed to psychological relief rather than physical recovery. However, low RMSSD persisted on match day, indicating incomplete physiological recovery despite stabilized subjective stress. The control group demonstrated stable HRV and VAS. These findings highlight the prolonged autonomic strain of rapid weight-cutting, emphasizing the need for careful management to safeguard athlete health and performance.
Detailed description
Objective:
This study aims to investigate the effects of rapid weight-cutting on objective (Heart Rate Variability - HRV, measured via RMSSD) and subjective (Visual Analog Scale - VAS) stress parameters in elite kickboxers. The evaluation will occur across seven specific time points: Weigh-in Morning, Pre-Weigh-in, Post-Weigh-in, Post-Weigh-in Meal, Match Day Morning, Pre-Match, and Post-Match.
Study Design:
An observational comparative design will be employed to assess objective and subjective stress responses related to weight-cutting in elite kickboxers. The study will take place during the Senior European Kickboxing Championship in Greece, from November 2 to November 10, 2024, under real competition conditions. Two groups will be included: a weight-cutting group and a non-weight-cutting group. This design will enable comparisons between objective (RMSSD) and subjective (VAS) stress measures, as well as between athletes who reduce weight and those who do not. Data will be collected at seven key time points to capture stress variations during the weight-cutting and competition phases.
Participants:
Elite kickboxers will be selected based on specific inclusion criteria. A sample size calculation using G*Power, based on an ANOVA with repeated measures and within-between interaction, determined a minimum of 22 participants to ensure adequate statistical power. Parameters include an effect size of 0.25, an alpha level of 0.05, and a power of 0.90. Accounting for potential data loss, the study targets 25 participants, with 12 in the weight-cutting group and 13 in the non-weight-cutting group. Participants will be active male elite kickboxers, aged 18-35, with at least five years of national or international competitive experience. The weight-cutting group will consist of athletes losing at least 5% of their body weight within 48 hours before the weigh-in, while the non-weight-cutting group will include those with no weight-cutting procedures and a maximum weight loss of 2% during pre-weigh-in training. Participation will be voluntary, with athletes provided detailed information about the study's purpose, methods, and risks, and written informed consent will be obtained. Confidentiality will be ensured, and data will be used solely for research purposes. The study has been approved by the Erzurum Technical University Scientific Research and Publication Ethics Committee (Meeting No: 10, Decision No: 10, Date: 12.09.2024).
Data Collection:
Data collection will focus on objective and subjective stress parameters using HRV and VAS. Objective stress will be measured via RMSSD values, recorded with Apple Watch Series 8 devices equipped with photoplethysmography technology. Participants will wear the device in a calm, seated position for five-minute intervals to ensure reliable HRV data. Subjective stress will be assessed using the VAS, where participants rate their perceived stress on a scale. Measurements will occur at seven time points surrounding the weigh-in and competition period: Weigh-in Morning, Pre-Weigh-in, Post-Weigh-in, Post-Weigh-in Meal, Match Day Morning, Pre-Match, and Post-Match.
Data Analysis:
Data will be analyzed using SPSS version 26. Pairwise group comparisons will use Hedges' g effect size calculations, adjusted for small sample sizes, and interpreted classification (trivial < 0.2, small 0.2-0.59, moderate 0.60-1.19, large 1.20-1.99, very large 2.0-3.99, nearly perfect > 4.0). Changes across the seven time points for RMSSD and VAS will be examined with repeated measures ANOVA, including within-between interactions. Significant effects or interactions will be followed by Bonferroni-adjusted post hoc tests to control for multiple comparisons. Partial eta-squared (η²ₚ) values will be reported to evaluate practical significance. Statistical significance will be set at p < 0.05.
Study design
- Observational model
- Other
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| weight-cutting group | – | –Athletes in the weight-cutting group were defined as those who had lost at least 5% of their body weight within the 48 hours prior to weigh-in. |
| control group | – | –Participants in the non-weight-cutting group did not engage in any weight-cutting procedures |
Who may qualify
- Ages
- 16 to 35 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
- Study population
- The study population consisted of elite male kickboxers competing at the Senior European Kickboxing Championship in Greece. Participants were aged 18 to 35 years and had a minimum of 5 years of competitive experience at the national or international level. Athletes were divided into two groups: Weight-Cutting Group (n = 12): Athletes who lost at least 5% of their body weight within 48 hours prior to weigh-in. Control Group (n = 13): Athletes who maintained their regular training and nutrition, with no more than 2% weight fluctuation before the competition. All participants underwent heart rate variability (HRV) assessments using photoplethysmography (PPG) via Apple Watch Series 8 and subjective stress evaluations using the Visual Analog Scale (VAS) at seven time points from weigh-in morning to post-match. Participants were selected based on strict inclusion and exclusion criteria to ensure comparability between groups.
Key inclusion criteria (4 listed)
- Elite male kickboxers aged between 18 and 35 years
- Minimum 5 years of competitive experience at the national or international level
- Actively competing in the Senior European Kickboxing Championship
- For the weight-cutting group: Must have lost at least 5% of body weight within the 48 hours prior to weigh-in
Key exclusion criteria (5 listed)
- Athletes who lost between 3-4% of their body weight, as they do not fit into either group
- History of cardiovascular diseases
- History of metabolic disorders
- Any medical condition that could affect HRV measurements
- Current or recent injuries (within the last 3 months) that could impair performance or stress responses
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Heart Rate Variability (HRV) - RMSSD Changes Over Time
Time frame: Baseline (Weigh-in Morning), immediately before weigh-in, immediately after weigh-in, post-weigh-in meal, morning of match day, immediately before match, immediately after match
Heart Rate Variability (HRV) was assessed using the Root Mean Square of the Successive Differences (RMSSD) to evaluate autonomic nervous system stress responses. RMSSD values were measured to determine the impact of rapid weight-cutting on physiological stress and recovery. Lower RMSSD values indicate higher physiological stress and impaired autonomic function.
1 secondary outcome
Subjective Stress Levels (VAS Scores) Over Time
Time frame: Baseline (Weigh-in Morning), immediately before weigh-in, immediately after weigh-in, post-weigh-in meal, morning of match day, immediately before match, immediately after match
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 7 Mar 2025.
- Derived from this study: PubMed 41919118Karababa B, Ulupinar S, Gencoglu C, Asan S, Bedir D, Ince I, Cabuk S, Canyurt F, Ozbay S, Kaya K. Cutting weight, gaining stress: the hidden battle that outweighs fight day tension in kickboxing. Front Psychol. 2026 Mar 16;17:1762659. doi: 10.3389/fpsyg.2026.1762659. eCollection 2026.
- Individual participant dataSharing planned: Yes. De-identified individual participant data (IPD) will be shared with researchers upon reasonable request. The following data will be available: Heart Rate Variability (HRV) data (RMSSD values) collected at seven time points Visual Analog Scale (VAS) stress scores at seven time points Basic demographic data (age, weight category, competition level) Access and Conditions: Data will be available after study publication for researchers conducting related studies in sports science, physiology, or psychology. Researchers must submit a formal request, including a study proposal, to the corresponding author (Burak Karababa, burak.karababa@erzurum.edu.tr). Access will be granted upon approval and agreement to data use terms, ensuring confidentiality and ethical research practices.
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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?
An observational study of HRV and Psychological Adaptation, run by Erzurum Technical 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 4 inclusion and 5 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 7 Mar 2025. 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?
Heart Rate Variability (HRV) - RMSSD Changes Over Time (time frame: Baseline (Weigh-in Morning), immediately before weigh-in, immediately after weigh-in, post-weigh-in meal, morning of match day, immediately before match, immediately after match). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06860204, which also lists 1 linked publication.
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 7 Mar 2025.