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Enrolling by Invitation

NCT Number: NCT07170930

The Effect of a Training Programme in the Variation of Fitness Parameters, Physiological, Hematological and Biochemical Indicators of Soccer Players During the Preseason Period

The goal of this study is to investigate the effects of varying friendly match-play exposure during the late pre-season on physiological, biochemical, and performance adaptations in soccer players. It is hypothesized that (i) significant changes will occur across the pre-season in both the extended- and limited-play groups when analysed independently; (ii) distinct group-specific adaptations will emerge by the end of the preparatory period; and (iii) match-play exposure, when analysed across all participants, will be significantly correlated with physiological and performance outcomes at pre-season completion. Players from a randomly selected team will be assessed at three time points: pre-season start, mid-pre-season (MPS), and pre-competition phase (PC). Assessments will include anthropometry, physical performance, and markers of muscle damage, inflammation, hormonal status, and haematology. Based on the total match-play time of 8 friendly games during the late pre-season, players will be retrospectively categorised into extended-play (EP) and limited-play (LP) cohorts.time of 8 friendly games during the late pre-season, players will be retrospectively categorised into extended-play (EP) and limited-play (LP) cohorts.

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Key information

Conditions

Athletic Performance Exercise Physiology Exercise Test Exercise-induced Inflammation Inflammation Muscle Damage Pathologic Processes Pathological Conditions, Signs and Symptoms Physical Fitness Pre-season Training Soccer

Age range

18 year–35 year

Sex eligibility

Male

Study type

Observational

Primary location

School of Physical Education and Sports Science, National and Kapodistrian University of Athens

Athens, Daphni, 17237, Greece

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Male participants
  • Aged 18 years or older
  • Non-smokers
  • Injury-free for the past 6 months
  • Medication-free for the past 6 months
  • Abstinent from alcohol
  • Living at an altitude below 1500 meters
  • Committed exclusively to soccer (no participation in other sports)

Exclusion criteria

  • History of serious injuries (e.g., fractures, ligament tears) within the past 6 months
  • Chronic medical conditions such as cardiovascular disease, diabetes, or respiratory disorders
  • Current use of performance-enhancing drugs or supplements
  • Participation in non-soccer-related sports or activities during the study period

Treatment and study plan

Friendly Match-Play Exposure: extended vs. limited

Other

This research explores the multidimensional physiological and biochemical responses to differing volumes of friendly match-play (i.e., extended vs. limited) during the late pre-season phase in soccer players.

Primary outcomes

  1. Body Mass

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Body mass measured at standard anatomical sites using a calibrated scale to track longitudinal changes over the pre-season.

    Unit of Measure: kg

  2. Body Fat

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Body fat percentage measured using skinfold calipers at standard sites to monitor longitudinal changes.

    Unit of Measure: %

  3. Rate of Perceived Exertion (RPE)

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Participants rate exertion during standardized training sessions using the Borg Scale (6 = no exertion, 20 = maximal exertion).

    Unit of Measure: Borg 6-20 scale

  4. Glucose

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Fasting blood glucose measured to track metabolic changes over pre-season.

    Unit of Measure: mg/dL

  5. Cholesterol

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Total serum cholesterol measured to assess lipid profile adaptations.

    Unit of Measure: mg/dL

  6. Triglycerides

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Serum triglycerides measured to monitor metabolic response to training.

    Unit of Measure: mg/dL

  7. SGOT (AST)

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Serum glutamic-oxaloacetic transaminase measured to assess liver/muscle stress.

    Unit of Measure: U/L

  8. SGPT (ALT)

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Serum glutamic-pyruvic transaminase measured to monitor liver/muscle stress.

    Unit of Measure: U/L

  9. Creatine Phosphokinase (CPK)

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: CPK measured to detect skeletal muscle damage.

    Unit of Measure: U/L

  10. Myoglobin

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Myoglobin measured as a marker of muscle damage.

    Unit of Measure: ng/mL

  11. Iron

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Serum iron measured to assess iron status.

    Unit of Measure: µg/dL

  12. Ferritin

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Serum ferritin measured to monitor iron storage.

    Unit of Measure: ng/mL

  13. C-Reactive Protein (CRP)

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: CRP measured as a marker of systemic inflammation.

    Unit of Measure: mg/L

  14. High-sensitivity CRP (hs-CRP)

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: hs-CRP measured to detect low-grade inflammation.

    Unit of Measure: mg/L

  15. Interleukin-6 (IL-6)

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: IL-6 measured from serum to assess inflammatory response.

    Unit of Measure: pg/mL

  16. Tumor Necrosis Factor-alpha (TNF-α)

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: TNF-α measured as a marker of systemic inflammation.

    Unit of Measure: pg/mL

  17. Testosterone

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Serum testosterone measured to assess hormonal adaptations.

    Unit of Measure: ng/dL

  18. Cortisol

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Serum cortisol measured to monitor stress response.

    Unit of Measure: µg/dL

  19. Testosterone-Cortisol Ratio

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Calculated ratio to estimate anabolic-catabolic balance.

    Unit of Measure: Ratio

  20. Red Blood Cells (RBC)

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: RBC count measured from blood to assess oxygen transport capacity.

    Unit of Measure: million cells/µL

  21. Hemoglobin

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Hemoglobin measured to evaluate oxygen-carrying capacity.

    Unit of Measure: g/dL

  22. Hematocrit

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Hematocrit measured as percentage of RBC in blood.

    Unit of Measure: %

  23. White Blood Cells (WBC)

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: WBC count measured to monitor immune function.

    Unit of Measure: cells/µL

  24. Platelets

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Platelet count measured to assess hematological health.

    Unit of Measure: cells/µL

  25. Countermovement Jump Height

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Jump height measured (cm) to assess lower-limb explosive power.

    Unit of Measure: cm

  26. Knee Extensor Power, Dominant Leg

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Measured using isokinetic dynamometer.

    Unit of Measure: Watts

  27. Knee Extensor Power, Non-Dominant Leg

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Measured using isokinetic dynamometer.

    Unit of Measure: Watts

  28. Knee Flexor Power, Dominant Leg

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Measured using isokinetic dynamometer.

    Unit of Measure: Watts

  29. Knee Flexor Power, Non-Dominant Leg

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Measured using isokinetic dynamometer.

    Unit of Measure: Watts

  30. 10-m Sprint Time

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Sprint time measured using photocell gates; lower times indicate better performance.

    Unit of Measure: seconds

  31. T-Test Agility

    Time frame: Each measure assessed at Baseline (pre-season start), 4 weeks (mid-pre-season), and 8 weeks (pre-competition phase).

    Description: Participants perform T-test agility course; lower times indicate better agility.

    Unit of Measure: seconds

Sponsors and collaborators

Lead sponsor

Emmanouil D. Zacharakis

Other

Registry information

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Sep 12, 2025
Registry last updated
Sep 19, 2025

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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