Which among the following can be assessed by the estimation of 3-methylhistidine in urine?

The study of tissue protein breakdown in vivo is difficult, because amino acids released during intracellular breakdown of proteins can be extensively reutilized for protein synthesis within the cell, or the amino acids may be transpoed to other organs where they enter anabolic pathways. However, actin and myosin are methylated by a posttranslational reaction, forming 3-methylhistidine. During intracellular breakdown of actin and myosin, 3-methylhistidine is released and excreted into the urine. The urinary output of the methylated amino acid provides a reliable index of the rate of myofibrillar protein breakdown in the musculature of human subjects. Ref: Murray R.K. (2011). Chapter 49. Muscle & the Cytoskeleton. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.