“…A large part of the studies used a single sensor, usually located on the back (lower back, L3 or L5 vertebrae) [ 24 , 27 , 30 , 37 , 39 , 42 ], or in some cases on the sternum [ 29 , 41 ], chest [ 32 ], or foot [ 6 ]. Three studies employed two IMUs, which were located on the same part of the body: feet [ 26 ], shins [ 35 ], and heels [ 36 ]. Studies that employed 3 IMUs [ 18 , 33 ], 5 IMUS [ 15 , 25 , 31 , 38 , 40 ], or 6 IMUs [ 28 , 34 ] combined different body positions as the thighs, shins, feet, shanks, back, ankles, pelvis, or sternum.…”