We review the recent literature on the interplay between mild vitamin D deficiency and skeletal muscle strength and performance.

Preclinical studies indicate that vitamin D is important in muscle proliferation, differentiation and mitochondrial function, whereas some epidemiological studies demonstrate associations with muscle strength and low physical performance. Recent studies have implicated vitamin D deficiency development of frailty and sarcopenia in the older population. Some small studies have assessed its impact on muscle function in special circumstances such as elite sport and critical illness. Advances in liquid chromatography/mass spectrometry technologies have allowed the inter-relationships between the vitamin D metabolome and muscle phenotype to be characterized. There is evidence of distinct effects on human skeletal muscle gene expression between vitamin D metabolites.