The Combined Effect of Resistance Training and Vitamin D Supplement on Skeletal Muscle Hypertrophy: A Review

Context: 

Resistance training (RT) and vitamin D are both utilized as interventions for muscle hypertrophy. Multiple studies have examined the impact of RT with and without vitamin D supplementation on muscle hypertrophy. There is currently no existing review study that has specifically investigated the combined effect of RT and vitamin D supplementation on skeletal muscle hypertrophy. This review article compiled studies examining the impact of both RT and vitamin D interventions on muscle hypertrophy.

Evidence Acquisition: 

Three databases (PubMed, ScienceDirect, and Google Scholar) were searched until September 9, 2022. Only original articles written in English were included. The findings of the studies were analyzed and categorized into two sections: cross-sectional areas and muscle performance.

 Very limited studies examined the effect of RT and vitamin D on hypertrophy and skeletal muscle function. The impact of RT and vitamin D on signaling pathways of protein synthesis and skeletal muscle hypertrophy was investigated separately, and the simultaneous effect of these two interventions was explored in a few studies.

 The proteins involved in the signaling pathway of muscle hypertrophy were examined in only three animal studies. Therefore, more field/clinical trials in the human model should investigate the effect of these two interventions on the degree of hypertrophy and muscle function. Besides, both in human studies using muscle biopsy and in animal studies at the cellular level, the expression of genes and proteins involved in signaling pathways affecting protein synthesis and muscle hypertrophy should be studied further to determine the simultaneous effect of these two interventions.