This data set refers to the study registered at clinicaltrials.gov (ref. n.: NCT03382366). This observational, cross-sectional, pilot study was approved by the Ethical Committee of Vita-Salute San Raffaele University (ref. n.: 17/INT/2017) and all procedures were performed in compliance with current national and international laws and regulations governing the use of human subjects (Declaration of Helsinki). The association between the quantity and composition of skeletal muscle and the decline in physical function in elderly is poorly understood. Therefore, the primary aim of this cross-over study was to investigate the association between thigh intramuscular adipose tissue infiltration, appendicular muscle mass and risk of fall in postmenopausal osteoporotic elder women. Second, we aimed at examining the differences in muscle mass, IMAT and risk of fall in the same sample of older subjects after being classified as sarcopenic or non sarcopenic on the basis of the dual energy X-ray absorptiometry-based Appendicular Skeletal Muscle Mass Index.