NIR spectral signatures of flexor and extensor muscles of the upper and lower limb in humans at varying lengths

NIR spectroscopy provides the spectral signatures (i.e. “fingerprints”) of living human muscles, which represent specific, accurate, and reproducible measures of their overall biological status. We showed that chemometric analysis applied to NIR spectra acquired from the upper limb distinguishes the biceps from the triceps. We acquired muscles reflectance spectra in the Vis-SWIR regions (350-2500 nm), utilizing an ASD FieldSpec 4™ Standard-Res Spectroradiometer with a spectral sampling capability of 1.4 nm at 350-1000 nm and 1.1 nm at 1001-2500 nm. Optical spectroscopy proves effective for studying human muscles in vivo and contribute to non-invasive more thorough evaluation of the muscular system.