Journal Article

Comparative analysis of single vs. two-muscle training programs on upper body muscle growth

Kadhim, Hiba Jawad, Alsaedi, Haider Radhi Raheem, Alali, Ahmad Alhussin, Alfadhli, Bareq Rahman Hashim, Khlaifawi, Mustafa Mohsin Flayyih

2025

Overview

This study investigates the effects of different bodybuilding training methodologies—single muscle versus multiple muscle training—on upper body muscle growth. Despite the established benefits of resistance training for muscle hypertrophy, the optimal structuring of workouts remains debated. An experimental design was utilized, dividing 44 participants from the Iraqi Federation for Bodybuilding and Fitness into two groups, with one focusing on training a single muscle per session and the other on training two muscles per session over 12 weeks. Pre- and post-test measurements were taken to assess changes in chest, upper arm, and forearm circumferences, alongside strength gains. Statistical analysis using SPSS revealed significant increases in muscle size for both training approaches, with the single muscle group demonstrating superior hypertrophic outcomes. These findings suggest that training one muscle group per session may provide a more effective stimulus for muscle growth compared to training multiple groups simultaneously. The results contribute valuable insights into bodybuilding training practices, indicating that specific training strategies can optimize hypertrophy and enhance strength in bodybuilders.

• Publisher: Federación Española de Docentes de Educación Física (FEADEF)
• Subject: Bodybuilding / Bodybuilding Training Methods / Comparative Analysis / crecimiento muscular de la parte superior del cuerpo / Debates / entrenamiento de un solo músculo frente a entrenamiento de varios músculos / hipertrofia muscular / Multiple Muscle Training / Muscle Hypertrophy / Métodos de entrenamiento de culturismo / Single Muscle vs / Upper Body Muscle Growth