Journal of Advanced Biomedical Sciences
JABS
Mon, Jan 5, 2026
[Archive]
Winter 2026 (In Press)
Back to the articles list |
Back to browse issues page
1- Department of Physical Education and Sport Sciences, Dez.C., Islamic Azad University, Dezful, Iran , tanoorsaz@iau.ir
2- Department of Physical Education and Sport Sciences, Dez.C., Islamic Azad University, Dezful, Iran
2- Department of Physical Education and Sport Sciences, Dez.C., Islamic Azad University, Dezful, Iran
Abstract: (6 Views)
Background & Objectives: Optimizing metabolic health and physical performance in middle-aged male athletes is critical for long-term health maintenance and athletic sustainability. This study investigated the combined effects of an 8-week strength training (ST) program and creatine supplementation on anabolic hormones, metabolic indicators, inflammatory markers, and lean body mass (LBM) in 30- to 45-year-old male athletes, with particular emphasis on the potential moderating role of the ACTN3 genotype (R577X).
Materials & Methods: A randomized, placebo-controlled, 2 × 2 factorial design was employed, involving 48 recreationally trained male athletes who were randomly assigned to one of four groups: ST plus creatine (ST+C), ST plus placebo (ST+P), creatine supplementation alone, and a non-intervention control group (CON). The 8-week intervention consisted of supervised resistance training sessions and daily supplementation with either creatine or placebo. Venous blood samples were collected before and after the intervention to assess serum testosterone, growth hormone, cortisol, fasting glucose, insulin, homeostatic model assessment of insulin resistance (HOMA-IR), lipid profile parameters, and inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6). ACTN3 genotyping was performed using standard molecular techniques. Data were analyzed using paired t-tests and analysis of covariance (ANCOVA), with inclusion of an exercise × creatine interaction term.
Results: The combined ST+C intervention resulted in a significant increase in LBM (p < 0.01, Cohen’s d = 0.85) and a significant improvement in insulin sensitivity, as evidenced by reduced HOMA-IR values (p < 0.05, Cohen’s d = 0.62), compared with all other groups. Creatine supplementation alone demonstrated a non-significant trend toward increased testosterone concentrations (p = 0.07). Participants in the ST+P group exhibited significant improvements in LBM and insulin sensitivity; however, these changes were less pronounced than those observed in the ST+C group. No significant between-group differences were observed for cortisol levels or inflammatory markers. ACTN3 genotype did not significantly moderate any of the measured outcomes.
Conclusion: Concurrent strength training and creatine supplementation effectively enhance LBM and insulin sensitivity in middle-aged male athletes. Creatine supplementation appears to confer additional benefits beyond resistance training alone, particularly with respect to anabolic hormonal responses. These findings support the use of combined resistance training and creatine supplementation as an effective strategy for optimizing metabolic health and physical performance in this population.
Materials & Methods: A randomized, placebo-controlled, 2 × 2 factorial design was employed, involving 48 recreationally trained male athletes who were randomly assigned to one of four groups: ST plus creatine (ST+C), ST plus placebo (ST+P), creatine supplementation alone, and a non-intervention control group (CON). The 8-week intervention consisted of supervised resistance training sessions and daily supplementation with either creatine or placebo. Venous blood samples were collected before and after the intervention to assess serum testosterone, growth hormone, cortisol, fasting glucose, insulin, homeostatic model assessment of insulin resistance (HOMA-IR), lipid profile parameters, and inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6). ACTN3 genotyping was performed using standard molecular techniques. Data were analyzed using paired t-tests and analysis of covariance (ANCOVA), with inclusion of an exercise × creatine interaction term.
Results: The combined ST+C intervention resulted in a significant increase in LBM (p < 0.01, Cohen’s d = 0.85) and a significant improvement in insulin sensitivity, as evidenced by reduced HOMA-IR values (p < 0.05, Cohen’s d = 0.62), compared with all other groups. Creatine supplementation alone demonstrated a non-significant trend toward increased testosterone concentrations (p = 0.07). Participants in the ST+P group exhibited significant improvements in LBM and insulin sensitivity; however, these changes were less pronounced than those observed in the ST+C group. No significant between-group differences were observed for cortisol levels or inflammatory markers. ACTN3 genotype did not significantly moderate any of the measured outcomes.
Conclusion: Concurrent strength training and creatine supplementation effectively enhance LBM and insulin sensitivity in middle-aged male athletes. Creatine supplementation appears to confer additional benefits beyond resistance training alone, particularly with respect to anabolic hormonal responses. These findings support the use of combined resistance training and creatine supplementation as an effective strategy for optimizing metabolic health and physical performance in this population.
Keywords: Strength Training, Creatine Supplementation, Middle-Aged Athletes, Metabolic Health, Randomized Trial
Type of Study: Research |
Subject:
Physiology
Received: 2025/07/24 | Revised: 2026/01/4 | Accepted: 2025/10/27
Received: 2025/07/24 | Revised: 2026/01/4 | Accepted: 2025/10/27
Send email to the article author
| Rights and permissions | |
 |
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. |
This work is licensed under a Creative Commons — Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)