MEASUREMENT OF SKELETAL-MUSCLE - LABORATORY AND EPIDEMIOLOGIC METHODS

Despite skeletal muscle's central role in the pathogenesis of sarcopen ia, measurement methods remain under investigated and inadequately val idated; Our review indicates that skeletal muscle (SM) measurement met hods quantify different components and properties of muscle, ranging f rom the atomic to whole-body levels of body composition. Laboratory me thods tend to measure whole body SM (e.g., total muscle protein, muscl e cell mass, and adipose tissue-free SM components) while epidemiologi cal methods tend to measure regional muscle (e.g., anatomic SM of an e xtremity). Advances in computerized axial tomography and magnetic reso nance imaging methods now allow accurate estimates of whole body and r egional SM and promise to finally permit comprehensive in vivo studies of SM biology and methodology. These imaging methods may help to reso lve many of the confusing issues that surround the investigation of th is major body composition component.