“…Four studies described system designs and therefore are not listed in the table [ 13 , 14 , 18 , 22 ]. Despite the heterogeneity of effectiveness and outcome measures, a few subthemes could be identified: accuracy of technology (n = 2 [ 15 , 30 ]), usability and engagement (n = 7 [ 14 , 16 , 17 , 21 , 27 , 29 , 31 ]), qualitative perception and acceptance of users towards technology (n = 9 [ 14 , 19 – 21 , 25 , 26 , 29 , 31 , 33 , 34 ]), behaviour change metrics (e.g. improved physical activity level, n = 8 [ 17 , 18 , 20 , 25 – 27 , 29 , 33 ])) and physical improvement (BMI change, n = 7 [ 19 , 21 , 23 , 26 , 32 – 34 ]).…”