|Many different theories and hypotheses have been developed and evolved to explain human skeletal muscle growth. To date, no single theory encompasses all known mechanisms of human skeletal muscle growth and many are poorly understood. Of the various theories and hypotheses, most have useful elements that partially explain how human skeletal muscle growth occurs in adults. Here, it is proposed that a unified theory of human skeletal muscle growth can integrate and explain human muscular growth in a simplified manner. A unified theory, called G-THHHEM-E Theory, relates all validated theories and hypotheses into a coherent system that identifies their interrelationships and provides a practical background to support resistance-training protocols. Specific examples were used to relate G-THHHEM-E Theory to resistance training principles. Understanding of the interrelationships between the elements of G-THHHEM-E Theory could help exercise physiologists and exercise-training practitioners design new strategies for developing resistance-training regimens.