A wearable motion tracking system (12) for capturing a relative position between a first body part (101) and a second body part (103) of said user (100) comprising a first measurement device (120a), a second measurement device (121a) and a computing device (150) that are configured such as to obtain by said computing device (150) a plurality of measurements between said first and second measurement devices (120a, 121a). Based on the plurality of measurements that comprises at least one distance measurement between said first and second measurement devices (120a, 121a) said computing device (150) is configured to compute, in three dimensions, a position of said second measurement device (121a) relative to said first measurement device (120a) for tracking the position of said second body part (103) relative to said first body part (101). The present invention further relates to a method of motion tracking.