Effects of Nattokinase Supplementation on Strength Recovery and Muscle Damage Biomarkers Following Exercise-Induced Muscle Injury: A Pilot Study

N/AActive Not RecruitingNCT07836634

National Taiwan Sport University14 enrolled

Overview

This pilot study aims to investigate whether 4 weeks of nattokinase supplementation (2,000 FU/day) affects recovery following exercise-induced muscle damage in healthy adult men. Approximately 12 to 16 participants aged 18 to 40 years will receive either nattokinase or a matching placebo during the supplementation period. After supplementation, participants will complete an exercise protocol designed to induce temporary muscle damage. Recovery will be evaluated using measures of muscle strength and exercise performance, muscle soreness, blood lactate, muscle oxygenation, and blood biomarkers related to muscle damage, inflammation, and oxidative stress. Measurements will be performed before and after the exercise-induced muscle damage protocol, including follow-up assessments during the recovery period. The study is intended to provide preliminary information on the potential effects of nattokinase supplementation on muscle recovery after strenuous exercise.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Enrollment

Conditions

Exercise-induced Muscle Damage

Interventions

Eligibility

Sex: MALEMin age: 18 YearsMax age: 40 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Male participants aged 18 to 40 years. * Regular exercise habits, defined as exercising at least 3 times per week, including at least 1 resistance-training session per week, with a stable exercise routine maintained during the previous 3 months. * No cardiovascular, metabolic, neurological, or musculoskeletal diseases that would prevent safe participation in the exercise testing, as assessed by the research team. * Not currently taking medications or dietary supplements that may affect blood coagulation. * No known allergy to natto or soy products. Exclusion Criteria: * Current use of anticoagulant or antiplatelet medications. * History of bleeding disorders or abnormal blood coagulation. * Major surgery within the previous 3 months. * Known cardiovascular, renal, or other major chronic diseases. * History of severe lower-extremity musculoskeletal injury, such as fracture, ligament injury, or meniscal injury, when judged by the research team to make exercise testing inappropriate. * Current acute inflammation, infection, or another physical condition considered unsuitable for participation in exercise. * Participation in high-intensity or systematic plyometric training within the previous month. * Students currently supervised by the principal investigator or individuals with a relevant conflict of interest with the study.

Outcomes

Primary Outcomes

Peak Force During Isometric Mid-Thigh Pull (IMTP)

Peak force during the isometric mid-thigh pull (IMTP) will be measured to assess maximal isometric strength. The highest value from three trials will be used for analysis.

Time frame: Day 0 baseline, pre-EIMD baseline, immediately post-EIMD, 24 hours post-EIMD, and 48 hours post-EIMD.

Countermovement Jump (CMJ) Height

Countermovement jump height will be measured to assess lower-limb explosive performance. The highest value from three trials will be used for analysis.

Time frame: Day 0 baseline, pre-EIMD baseline, immediately post-EIMD, 24 hours post-EIMD, and 48 hours post-EIMD.

Blood Lactate Concentration

Blood lactate concentration will be measured before and after the Wingate Anaerobic Test (WAnT) to assess lactate production and clearance. The WAnT will be used as a standardized high-intensity exercise stimulus.

Time frame: During the Day 0, pre-EIMD, and immediately post-EIMD WAnT assessments; blood lactate will be measured before exercise, immediately after exercise, and at 3, 5, and 10 minutes post-exercise.

Muscle Oxygen Saturation (SmO₂)

Muscle oxygen saturation (SmO₂) will be measured using near-infrared spectroscopy (NIRS) to assess changes in muscle oxygenation.

Time frame: Day 0 baseline, pre-EIMD baseline, immediately post-EIMD, 2 hours post-EIMD, 24 hours post-EIMD, and 48 hours post-EIMD.

Total Hemoglobin (THb)

Total hemoglobin (THb) will be measured using near-infrared spectroscopy (NIRS) to assess changes in local muscle blood volume.

Time frame: Day 0 baseline, pre-EIMD baseline, immediately post-EIMD, 2 hours post-EIMD, 24 hours post-EIMD, and 48 hours post-EIMD

Subjective Muscle Soreness Using Visual Analogue Scale (VAS)

Subjective muscle soreness will be assessed using a 100-mm visual analogue scale (VAS), ranging from no soreness to worst possible soreness.