The elasticity of human tissue is a parameter that indicates tissue quality or condition. Measurement of elasticity could also be useful in assessing the activity of skeletal muscle. Musculoskeletal (MSK) ultrasound elastography appears to be suitable for measuring muscle activity in clinical settings because it offers real-time measurement with patients in less restricted postures and joint positions. MSK ultrasound real-time tissue elastography (RTE) is one of the elastography techniques and uses light tissue compression with an ultrasound transducer. The compression is applied to generate strain in living tissues, and then, RTE shows mapping of strain distribution within the tissues in real time. Elasticity in a target tissue can be calculated by comparing the strain in the tissue with that in another tissue.