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Completed

NCT Number: NCT07440394

Evaluation of Pine Bark Extract for Anti-fatigue Ergogenic Properties

This research proposal aims to elucidate the physiological responses to pine bark extract supplementation during a single bout of high-intensity cycling exercise at 70% VO₂max and the subsequent recovery phase. Specifically, the study seeks to investigate the underlying mechanisms by which pine bark extract modulates exercise-induced fatigue and metabolic fitness, and to determine whether such supplementation may enhance endurance performance in the post-recovery period.

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Key information

Conditions

Healthy

Age range

20 year–40 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

China Medical University

Taichung, Taiwan

About this study

The primary active component of natural pine bark extract (PBE) is proanthocyanidins, which possess antioxidant, anti-inflammatory, and endothelial function-enhancing properties. These attributes suggest its potential as an ergogenic aid to improve exercise performance. In this study, 14 healthy participants will be randomly assigned to receive either 300 mg/day of PBE or a placebo for 4 consecutive days. Following supplementation, participants will consume a low-calorie meal (300 kcal) accompanied by either the placebo or PBE and rest for one hour. One hour after capsule ingestion, participants will perform a 60-minute cycling exercise at 70% VO₂max. Upon completion of the exercise challenge, they will consume a post-exercise meal adjusted to body weight. After a 3-hour recovery period, subjects will undergo an anaerobic power test followed by an endurance test at 75% VO₂max to volitional exhaustion. Gas exchange and blood samples will be collected at multiple time points: pre- and post-initial cycling session, during the recovery phase, and following the exhaustive endurance test. Gas samples will be analyzed to determine rates of fat and carbohydrate oxidation. Blood biomarkers will be assessed for glucose, superoxidase dismutase (SOD), malondialdehyde (MDA), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), creatine kinase (CK), lactate dehydrogenase (LDH), and uric acid (UA).

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • A minimum of three years of regular exercise habits.

Exclusion criteria

  • Have smoking and drinking habits.
  • People who feel unwell due to other reasons during the experiment.
  • Individuals with respiratory disorders.
  • Severe lower limb musculoskeletal injuries within the past six months.

Treatment and study plan

Placebo (Placebo trial)

Other

The Placebo capsule supplement was taken for 4 days (3 capsules per day)

PBE (PBE trial)

Other

The PBE capsule supplement was taken for 4 days, with a daily dosage of 300 mg of PBE (equivalent to 3 capsules per day, each containing 100 mg of PBE).

Primary outcomes

  1. Time to Exhaustion (TTE)

    Time frame: Baseline and at the end of the 4-week crossover period.

    The total duration (in minutes) from the start of the graded exercise test until the participant reaches volitional exhaustion or can no longer maintain the required cadence of 60 RPM.

    Unit of Measure: Minutes

Secondary outcomes

  1. Serum Tumor Necrosis Factor-alpha (TNF-alpha) Concentration

    Time frame: 7 time points (Baseline, START, END, 0 min, 60 min, 120 min, 180 min in two ergometer trials) during each crossover trial.

    A pro-inflammatory cytokine measured in serum using a commercial ELISA kit (BioLegend) to evaluate the inflammatory response.Unit of Measure: Picograms per milliliter (pg/mL)

  2. Superoxide Dismutase (SOD) Activity

    Time frame: 7 time points (Baseline, START, END, 0 min, 60 min, 120 min, 180 min in two ergometer trials) during each crossover trial.

    biomarker used to evaluate total antioxidant capacity. Serum SOD activity is measured using a commercial colorimetric assay kit and read with an ELISA plate reader.Unit of Measure: Units per milliliter (U/mL).

  3. Blood Glucose Levels

    Time frame: 7 time points (Baseline, START, END, 0 min, 60 min, 120 min, 180 min in two ergometer trials) during each crossover trial.

    Estimated from blood using the glucometer to assess glycemic response during the trials.

  4. Uric Acid (UA) Levels

    Time frame: 7 time points (Baseline, START, END, 0 min, 60 min, 120 min, 180 min in two ergometer trials) during each crossover trial.

    Measured in serum as a marker of metabolic stress and muscle damage using commercial analytical reagents. Unit of Measure: Milligrams per deciliter (mg/dL).

  5. Lactate Dehydrogenase (LDH) Activity

    Time frame: 7 time points (Baseline, START, END, 0 min, 60 min, 120 min, 180 min in two ergometer trials) during each crossover trial.

    Description: A biomarker of muscle damage measured in serum using an automated clinical chemistry analyzer (Beckman Coulter AU5800).

    Unit of Measure: Units per Liter (U/L)

  6. Serum Interleukin-6 (IL-6) Concentration

    Time frame: 7 time points (Baseline, START, END, 0 min, 60 min, 120 min, 180 min in two ergometer trials) during each crossover trial.

    A pro-inflammatory cytokine measured in serum using a commercial ELISA kit (BioLegend) to evaluate the inflammatory response. Unit of Measure: Picograms per milliliter (pg/mL)

  7. Malondialdehyde (MDA) Levels

    Time frame: 7 time points (Baseline, START, END, 0 min, 60 min, 120 min, 180 min in two ergometer trials) during each crossover trial.

    A standard biomarker of lipid peroxidation. Serum MDA levels are determined using a commercial ELISA kit to assess oxidative stress status. Unit of Measure: micromolar (μM)

  8. Serum Creatine Kinase (CK) Concentration

    Time frame: 7 time points (Baseline, START, END, 0 min, 60 min, 120 min, 180 min in two ergometer trials) during each crossover trial.

    A biomarker of muscle damage measured in serum using an automated clinical chemistry analyzer (Beckman Coulter AU5800). Unit of Measure: Units per Liter (U/L)

  9. Carbohydrate (CHO) Oxidation Rate

    Time frame: 7 time points (Baseline, START, END, 0 min, 60 min, 120 min, 180 min in two ergometer trials) during each crossover trial.

    Determined using VO 2 and VCO 2 data collected during the cycling challenge. Calculated using the equation: 4.585×VCO2 -3.226×VO2 .

    Unit of Measure: grams per minute (g/min)

  10. Fat Oxidation Rate

    Time frame: 7 time points (Baseline, START, END, 0 min, 60 min, 120 min, 180 min in two ergometer trials) during each crossover trial.

    Determined using VO 2 and VCO 2 data collected during the cycling challenge. Calculated using the Frayn equation: 1.695×VO 2 -1.701×VCO 2 .

    Unit of Measure: grams per minute (g/min)

  11. Respiratory Exchange Ratio (RER)

    Time frame: 7 time points (Baseline, START, END, 0 min, 60 min, 120 min, 180 min in two ergometer trials) during each crossover trial.

    Calculated as the ratio of carbon dioxide production ($VCO_2$) to oxygen consumption ($VO_2$). It reflects the relative contribution of carbohydrates and fats to energy metabolism.

    Unit of Measure: Ratio (Unitless)

  12. Maximal Oxygen Consumption (VO2max)

    Time frame: Baseline and at the end of the 4-week crossover period.

    Measured using a graded exercise test on a stationary ergometer. VO2max is defined as the plateau in oxygen uptake despite an increase in workload, confirmed when at least two of the following criteria are met: (1) RER > 1.10, (2) VO2 plateau (< 2 ml/kg/min change), or (3) attainment of age-predicted maximum heart rate.

    Unit of Measure: ml/kg/min

  13. Profile of Mood States (POMS) - Vigor Subscale Score

    Time frame: Measured immediately after each cycling challenge at baseline and at the end of the 4-week crossover trial.

    A subscale of the POMS brief version used to evaluate the positive mood state of vigor. It consists of specific adjectives scored on a 5-point scale (1-5). Higher scores indicate higher levels of vigor. Unit of Measure: Units on a scale

  14. Profile of Mood States (POMS) - Self-esteem Subscale Score

    Time frame: Measured immediately after each cycling challenge at baseline and at the end of the 4-week crossover trial.

    A subscale of the POMS brief version used to evaluate the mood state of self-esteem. Scored on a 5-point scale (1-5). Higher scores indicate higher levels of self-esteem. Unit of Measure: Units on a scale

  15. Profile of Mood States (POMS) - Tension Subscale Score

    Time frame: Measured immediately after each cycling challenge at baseline and at the end of the 4-week crossover trial.

    A subscale of the POMS brief version used to evaluate the negative mood state of tension. Scored on a 5-point scale (1-5). Higher scores indicate higher levels of tension. Unit of Measure: Units on a scale

  16. Profile of Mood States (POMS) - Confusion Subscale Score

    Time frame: Measured immediately after each cycling challenge at baseline and at the end of the 4-week crossover trial.

    A subscale of the POMS brief version used to evaluate the negative mood state of confusion. Scored on a 5-point scale (1-5). Higher scores indicate higher levels of confusion. Unit of Measure: Units on a scale

  17. Profile of Mood States (POMS) - Anger Subscale Score

    Time frame: Measured immediately after each cycling challenge at baseline and at the end of the 4-week crossover trial.

    A subscale of the POMS brief version used to evaluate the negative mood state of anger. Scored on a 5-point scale (1-5). Higher scores indicate higher levels of anger. Unit of Measure: Units on a scale

  18. Profile of Mood States (POMS) - Fatigue Subscale Score

    Time frame: Measured immediately after each cycling challenge at baseline and at the end of the 4-week crossover trial.

    A subscale of the POMS brief version used to evaluate the negative mood state of fatigue. Scored on a 5-point scale (1-5). Higher scores indicate higher levels of fatigue. Unit of Measure: Units on a scale

  19. Profile of Mood States (POMS) - Depression Subscale Score

    Time frame: Measured immediately after each cycling challenge at baseline and at the end of the 4-week crossover trial.

    A subscale of the POMS brief version used to evaluate the negative mood state of depression. Scored on a 5-point scale (1-5). Higher scores indicate higher levels of depression. Unit of Measure: Units on a scale

Sponsors and collaborators

Lead sponsor

China Medical University Hospital

Other

Collaborators

  • China Medical University, Taiwan
  • National Science and Technology Council, Taiwan

Registry information

Important dates

Study start
2023
Primary completion
2023
Study completion
2023
First posted
Feb 27, 2026
Registry last updated
Feb 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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