Combined Myo-Reps and Traditional Resistance Training Promotes Greater Muscle Hypertrophy Without Altering Acute Decorin and Interleukin-1β Responses in Resistance-Trained Men

Rezaei, Bagher; Shalmazari, Sadegh Amani; Rajabi, Hamid; Tartibian, Bakhtiar

doi:10.22054/nass.2026.94181.1245

Combined Myo-Reps and Traditional Resistance Training Promotes Greater Muscle Hypertrophy Without Altering Acute Decorin and Interleukin-1β Responses in Resistance-Trained Men

Document Type : Research Paper

Authors

Bagher rezaei ¹

Sadegh Amani Shalmazari ²

Hamid Rajabi ³

Bakhtiar Tartibian ⁴

¹ PhD Student in Exercise Physiology, Kharazmi University (Tehran Branch), Tehran, Iran.

² Associate Professor of Exercise Physiology, Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Kharazmi University, Tehran, Iran

³ Professor of Exercise Physiology, Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Kharazmi University, Tehran, Iran.

⁴ Professor of Exercise Physiology, Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Allameh Tabataba’i University, Tehran, Iran.

https://doi.org/10.22054/nass.2026.94181.1245

Abstract

Purpose: This study investigated the acute serum responses of decorin and interleukin-1β (IL-1β) and the effects of 8 weeks of Myo-reps, traditional, and combined resistance training on rectus femoris muscle thickness and lower-body strength in men.
Methods: Thirty-six resistance-trained men (26.03 ± 4.22 years; BMI: 24.83 ± 3.05 kg/m²) were randomly assigned to traditional, Myo-reps, or combined training. Participants completed an 8-week program (3 sessions/week) with standardized volume and progressive intensity (75–85% 1RM). Serum decorin and IL-1β were measured before and immediately after the third training session during week 1. Rectus femoris muscle thickness was assessed by ultrasonography, and hack squat one-repetition maximum was measured before and after training. Data were analyzed using paired-samples t-tests and ANCOVA (p < 0.05).
Results: No between-group differences were found for serum decorin (p = 0.81) or IL-1β (p = 0.67). Decorin decreased only in the traditional group (p = 0.03), whereas IL-1β remained unchanged in all groups. Rectus femoris muscle thickness increased in the Myo-reps (p = 0.02) and combined (p = 0.001) groups, but not in the traditional group (p = 0.07). Muscle thickness differed between groups (p = 0.01), with greater increases in the combined than the traditional group (p = 0.01). Hack squat strength improved in all groups (p = 0.001), with no between-group differences (p = 0.51).
Conclusion: Combined Myo-reps and traditional resistance training produced greater increases in rectus femoris thickness than traditional resistance training alone without altering acute decorin or IL-1β responses. All protocols similarly improved lower-body strength.

Keywords

Muscle hypertrophy

Exercise-induced myokines

Extracellular matrix remodeling

Inflammatory biomarkers

ultrasonography

Strength adaptation

Subjects