Journal of Exercise & Organ Cross Talk
Journal of Eexercise & Organ Cross Talk

The effects of 8-week sport metric training on hematological profiles and physical fitness parameters in adolescent male soccer players

Articles in Press

Document Type : Original Article

Authors

Alireza Fereidani 1
Hossein Barzegari 2
Zahra Mosayebi 3
Bahman Hasanvand 4

1 Master’s Graduate in Exercise Physiology, Department of Physical Education and Sport Sciences, Islamic Azad University, Aligudarz Branch, Aligudarz, Iran

2 Ph.D. in Exercise Physiology, Faculty of Psychology and Educational Sciences, Department of Physical Education and Sport Sciences, Yazd University, Yazd, Iran

3 Assistant Professor, Department of Physical Education, Islamic Azad University, Aligudarz Branch, Aligudarz, Iran

4 Associate Professor,Department of Physical Education, Islamic Azad University, Khorramabad Branch, Khorramabad , Iran

10.22122/jeoct.2026.572254.1188
Abstract
This semi-experimental study employed a pre-test–post-test design with a control group to investigate the effects of an eight-week sport metric training program on selected hematological indices and physical performance variables in adolescent male soccer players. Thirty participants (aged 13–16 years) were randomly assigned to either an experimental group (n = 15) or a control group (n = 15). The experimental group performed sport metric training three sessions per week for eight weeks, in addition to their routine soccer training. The control group continued only their standard soccer sessions. Hematological indices (hemoglobin, hematocrit, and blood viscosity) were measured from venous blood samples, while physical performance was assessed using the 36-meter sprint test (for speed) and the Illinois agility test. Following the intervention, the experimental group showed significant improvements compared to the control group. Hemoglobin and hematocrit levels increased meaningfully (P ≤ 0.05), suggesting enhanced oxygen-carrying capacity of the blood. Blood viscosity decreased significantly (P ≤ 0.05), which may indicate improved blood flow and reduced circulatory resistance. In terms of physical performance, the experimental group exhibited substantial reductions in sprint time (36-meter sprint) and agility time (Illinois test), both reaching statistical significance (P ≤ 0.05) with large effect sizes. In conclusion, eight weeks of sport metric training produced favorable changes in hematological profiles and marked enhancements in speed and agility performance among adolescent male soccer players. The findings suggest that targeted, sport-specific training programs can serve as a valuable supplement to routine soccer training during adolescence, supporting both physiological development and on-field performance.

What is already known on this subject?

Soccer is one of the most popular and dynamic sports worldwide, requiring high levels of physical fitness, including aerobic capacity, muscular strength, speed, agility, and coordination.

 

What this study adds?

eight weeks of Sport Metric training is an effective intervention for improving hematological profiles and physical fitness factors in adolescent male soccer players, supporting its integration into youth soccer training programs.

Keywords

Soccer
Hematological indices
Physical fitness
Adolescents

Subjects

Acknowledgements

The authors would like to thank all individuals and groups who contributed to the completion of this research.

Funding

This study was derived from a Master’s thesis and was conducted without financial support from any company, organization, or institution institution with commercial interests in the results.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Compliance with ethical standards

Conflict of interest the authors declare that there is no conflict of interest in the present research.

Ethical approval All ethical guidelines were strictly followed. Written informed consent was obtained from participants and guardians. General health status was assessed prior to inclusion to minimize risks. No adverse events were reported, and participants could withdraw at any time.

Informed consent 

performed. 

Author contributions 

Conceptualization: A.F., Methodology: H.B.M., Software: Z.M., Validation: B.H.,; Formal analysis: Z.M.,; Investigation: A.F.,; Resources: H.B.M.,; Data curation: Z.M.,; Writing - original draft: A.F.,; Writing–review & editing B.H.,; Visualization: H.B.M.,; Supervision: Z.M.; Project administration: Z.M.,.; Funding acquisition: A.F.    

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Journal of Exercise & Organ Cross Talk

Articles in Press, Accepted Manuscript
Available Online from 30 March 2026

  • Receive Date 27 December 2025
  • Revise Date 15 February 2026
  • Accept Date 15 February 2026

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