AEROBIC ADAPTATION AND BIOMARKER RESPONSES IN COMBAT ATHLETES (AERO-BIO)

MYOSTATIN REDUCTION WITHIN THE MYOKINE-ADIPOKINE NETWORK PREDICTS AEROBIC ADAPTATION AFTER HIGH-INTENSITY INTERVAL TRAINING IN COMBAT ATHLETES

This randomized controlled study investigates the effects of sport-specific training on aerobic adaptation and circulating biomarker responses in trained combat athletes. Exercise induces systemic physiological adaptations through signaling molecules known as exerkines, including myokines and adipokines, which mediate communication between skeletal muscle and other metabolic organs.

Forty trained male kickboxers are randomly assigned to either an experimental training group or a control group. The experimental group performs an eight-week sport-specific conditioning program in addition to regular technical training, while the control group maintains their usual training routine.

Aerobic capacity is assessed using maximal oxygen uptake (VO₂max). Blood samples are collected before and after the intervention to determine circulating levels of exercise-responsive biomarkers, including myostatin, irisin, apelin, brain-derived neurotrophic factor (BDNF), fibroblast growth factor-21 (FGF21), and adiponectin.

The primary objective of the study is to evaluate whether changes in circulating biomarker responses are associated with improvements in aerobic performance. The findings may provide insight into the molecular mechanisms underlying exercise-induced physiological adaptation in combat athletes.

Study Overview

• Status: Completed
• Conditions: Athletic Performance; Aerobic Capacity; Exercise Adaptation; Combat Sports Training
• Intervention / Treatment: Behavioral: SPORT-SPECIFIC CONDITIONING PROGRAM

Detailed Description

Physical exercise induces complex physiological adaptations that involve coordinated responses across multiple organ systems. In recent years, increasing attention has been directed toward circulating signaling molecules collectively referred to as exerkines. These molecules include myokines and adipokines that are released during or after exercise and contribute to communication between skeletal muscle, adipose tissue, the liver, and the central nervous system. Through these signaling pathways, exercise influences metabolic regulation, mitochondrial remodeling, inflammation, and tissue adaptation.

Combat sports such as kickboxing require repeated high-intensity efforts interspersed with short recovery periods. These demands place substantial stress on both anaerobic and aerobic energy systems. Consequently, aerobic capacity plays an essential role in maintaining performance and supporting recovery during repeated bouts of high-intensity activity.

Although improvements in aerobic performance following structured training programs are well documented, less is known about the molecular mechanisms that accompany these adaptations in combat sport athletes. Emerging evidence suggests that exercise-responsive biomarkers such as myostatin, irisin, apelin, brain-derived neurotrophic factor (BDNF), fibroblast growth factor-21 (FGF21), and adiponectin may play important roles in regulating metabolic adaptation and muscle remodeling.

The present randomized controlled trial aims to investigate whether coordinated changes in circulating myokine-adipokine responses are associated with improvements in aerobic capacity in trained combat athletes. Forty elite male kickboxers are randomly assigned to either an experimental training group or a control group. The intervention group performs an eight-week sport-specific conditioning program three times per week in addition to regular technical training, whereas the control group maintains their habitual training routine.

Aerobic capacity is assessed using maximal oxygen uptake (VO₂max) measured during a graded treadmill exercise test with respiratory gas analysis. Venous blood samples are collected under fasting conditions before and after the intervention to evaluate circulating biomarker responses. Biomarkers are analyzed using enzyme-linked immunosorbent assay (ELISA) techniques.

The primary outcome of the study is the change in VO₂max following the training intervention. Secondary outcomes include changes in circulating concentrations of myostatin, irisin, apelin, BDNF, FGF21, and adiponectin. The study also examines associations between biomarker changes and aerobic performance adaptation.

This study may contribute to a better understanding of the physiological mechanisms underlying exercise-induced adaptation and provide insight into how circulating biomarker responses may reflect training responsiveness in combat sport athletes.

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Adıyaman Province
    • Adıyaman, Adıyaman Province, Turkey (Türkiye), 02200
      • Adiyaman University Faculty of Sport Sciences

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Male combat sport athletes aged between 18 and 25 years
• Minimum five years of competitive kickboxing experience
• Regular participation in training at least five days per week
• Currently competing at the national level

Exclusion Criteria:

• Musculoskeletal injury within the previous six months
• Cardiovascular or metabolic disease
• Use of medications or supplements that may affect metabolic or hormonal responses
• Participation in additional structured conditioning programs during the study period

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: SPORT-SPECIFIC TRAINING GROUP; PARTICIPANTS IN THIS GROUP PERFORMED AN EIGHT-WEEK SPORT-SPECIFIC CONDITIONING PROGRAM THREE TIMES PER WEEK IN ADDITION TO THEIR REGULAR COMBAT SPORT TRAINING.	Behavioral: SPORT-SPECIFIC CONDITIONING PROGRAM; PARTICIPANTS PERFORMED AN EIGHT-WEEK SPORT-SPECIFIC CONDITIONING PROGRAM DESIGNED TO IMPROVE AEROBIC CAPACITY. TRAINING SESSIONS WERE CONDUCTED THREE TIMES PER WEEK AND CONSISTED OF REPEATED HIGH-INTENSITY INTERVALS INTERSPERSED WITH SHORT RECOVERY PERIODS, REFLECTING THE PHYSIOLOGICAL DEMANDS OF COMBAT SPORTS.
No Intervention: CONTROL GROUP; PARTICIPANTS IN THIS GROUP CONTINUED THEIR USUAL COMBAT SPORT TRAINING WITHOUT ANY ADDITIONAL CONDITIONING PROGRAM.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
VO₂max	Baseline and after 8 weeks

Secondary Outcome Measures

Outcome Measure	Time Frame
Myostatin	Baseline and after 8 weeks
Irisin	Baseline and after 8 weeks
Apelin	Baseline and after 8 weeks
BDNF	Baseline and after 8 weeks
FGF21	Baseline and after 8 weeks
Adiponectin	Baseline and after 8 weeks

Collaborators and Investigators

• Sponsor: Adiyaman University
• Investigators: Principal Investigator: Eren Bozyılan, Adiyaman University

Publications and helpful links

General Publications

• MacInnis MJ, Gibala MJ. (2017). Physiological adaptations to interval training and the role of exercise intensity. Journal of Physiology, 595(9), 2915-2930.
• Chow LS, Gerszten RE, Taylor JM, Pedersen BK, et al. (2022). Exerkines in health, resilience and disease. Nature Reviews Endocrinology, 18(5), 273-289.

Study record dates

Study Major Dates

• Study Start (Actual): January 20, 2025
• Primary Completion (Actual): March 20, 2025
• Study Completion (Actual): March 25, 2025

Study Registration Dates

• First Submitted: March 11, 2026
• First Submitted That Met QC Criteria: March 11, 2026
• First Posted (Actual): March 16, 2026

Study Record Updates

• Last Update Posted (Actual): March 16, 2026
• Last Update Submitted That Met QC Criteria: March 11, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Adipokines; VO2max; Myokines; Myostatin; Exercise Physiology; Aerobic Adaptation; Combat Athletes
• Other Study ID Numbers: ADYU-AEROBIC-ADAPTATION-2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Individual participant data may be made available to qualified researchers upon reasonable request to the corresponding author, following publication of the study results and in accordance with institutional policies and ethical guidelines.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No