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

NCT07170930 | Enrolling By Invitation

• 1 other identifier: ERC-002/2023
• Study Type: observational
• Target: 24
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Athletic Performance; Soccer; Muscle Damage; Inflammation; Exercise Test; Pre-season Training; Exercise Physiology; Physical Fitness; Exercise-induced Inflammation

Keywords

Pre-season training; Match-play exposure; Physiological adaptation; Biochemical markers; Recovery strategies; Training intensity; Physiological stress; Football; Aerobic-anaerobic; Effect; Athletic; Performance adaptation

Outcome Measures

Primary Outcomes (31)

• Body Mass

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

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

• Body Fat

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

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

• Rate of Perceived Exertion (RPE)

  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

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

• Glucose

  Description: Fasting blood glucose measured to track metabolic changes over pre-season. Unit of Measure: mg/dL

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

• Cholesterol

  Description: Total serum cholesterol measured to assess lipid profile adaptations. Unit of Measure: mg/dL

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

• Triglycerides

  Description: Serum triglycerides measured to monitor metabolic response to training. Unit of Measure: mg/dL

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

• SGOT (AST)

  Description: Serum glutamic-oxaloacetic transaminase measured to assess liver/muscle stress. Unit of Measure: U/L

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

• SGPT (ALT)

  Description: Serum glutamic-pyruvic transaminase measured to monitor liver/muscle stress. Unit of Measure: U/L

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

• Creatine Phosphokinase (CPK)

  Description: CPK measured to detect skeletal muscle damage. Unit of Measure: U/L

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

• Myoglobin

  Description: Myoglobin measured as a marker of muscle damage. Unit of Measure: ng/mL

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

• Iron

  Description: Serum iron measured to assess iron status. Unit of Measure: µg/dL

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

• Ferritin

  Description: Serum ferritin measured to monitor iron storage. Unit of Measure: ng/mL

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

• C-Reactive Protein (CRP)

  Description: CRP measured as a marker of systemic inflammation. Unit of Measure: mg/L

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

• High-sensitivity CRP (hs-CRP)

  Description: hs-CRP measured to detect low-grade inflammation. Unit of Measure: mg/L

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

• Interleukin-6 (IL-6)

  Description: IL-6 measured from serum to assess inflammatory response. Unit of Measure: pg/mL

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

• Tumor Necrosis Factor-alpha (TNF-α)

  Description: TNF-α measured as a marker of systemic inflammation. Unit of Measure: pg/mL

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

• Testosterone

  Description: Serum testosterone measured to assess hormonal adaptations. Unit of Measure: ng/dL

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

• Cortisol

  Description: Serum cortisol measured to monitor stress response. Unit of Measure: µg/dL

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

• Testosterone-Cortisol Ratio

  Description: Calculated ratio to estimate anabolic-catabolic balance. Unit of Measure: Ratio

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

• Red Blood Cells (RBC)

  Description: RBC count measured from blood to assess oxygen transport capacity. Unit of Measure: million cells/µL

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

• Hemoglobin

  Description: Hemoglobin measured to evaluate oxygen-carrying capacity. Unit of Measure: g/dL

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

• Hematocrit

  Description: Hematocrit measured as percentage of RBC in blood. Unit of Measure: %

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

• White Blood Cells (WBC)

  Description: WBC count measured to monitor immune function. Unit of Measure: cells/µL

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

• Platelets

  Description: Platelet count measured to assess hematological health. Unit of Measure: cells/µL

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

• Countermovement Jump Height

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

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

• Knee Extensor Power, Dominant Leg

  Description: Measured using isokinetic dynamometer. Unit of Measure: Watts

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

• Knee Extensor Power, Non-Dominant Leg

  Description: Measured using isokinetic dynamometer. Unit of Measure: Watts

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

• Knee Flexor Power, Dominant Leg

  Description: Measured using isokinetic dynamometer. Unit of Measure: Watts

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

• Knee Flexor Power, Non-Dominant Leg

  Description: Measured using isokinetic dynamometer. Unit of Measure: Watts

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

• 10-m Sprint Time

  Description: Sprint time measured using photocell gates; lower times indicate better performance. Unit of Measure: seconds

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

• T-Test Agility

  Description: Participants perform T-test agility course; lower times indicate better agility. Unit of Measure: seconds

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

Study Arms (2)

Extended-Play

Participants with higher cumulative friendly match-play exposure during the late pre-season phase.

Other: Friendly Match-Play Exposure: extended vs. limited

Limited-Play

Participants with lower cumulative friendly match-play exposure during the late pre-season phase.

Other: Friendly Match-Play Exposure: extended vs. limited

Interventions

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.

Extended-Play; Limited-Play

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Probability Sample

Study Population

All participants are highly active soccer players (i.e., \>1000 MET-min·week-¹) and compete at national-level standards.

You may qualify if:

• 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)

You may not qualify if:

• 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

Sponsors & Collaborators

• Emmanouil D. Zacharakis: lead

Study Sites (1)

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

Athens, Daphni, 17237, Greece

Location

Biospecimen

Retention: SAMPLES WITHOUT DNA

Whole blood (for haematological, endocrine, inflammatory, and muscle damage markers)

MeSH Terms

Conditions

Inflammation

Condition Hierarchy (Ancestors)

Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: PhD

Study Record Dates

• First Submitted: July 1, 2025
• First Posted: September 12, 2025
• Study Start: July 1, 2025
• Primary Completion: September 15, 2025
• Study Completion: September 15, 2025
• Last Updated: September 19, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will share

Locations

GR (1)