Range values for oxygenated and deoxygenated haemoglobin in both study groups using Device A. Left and right plantar 1st (L1M, R1M), 3rd (L3M, R3M), and 5th (L5M, R5M) metatarsophalangeal joints; left and right dorsal 3rd metatarsophalangeal joints (L3D, R3D) and the left and right heel (LH, RH)