Inclusion Criteria:  Patients who underwent limb salvage surgery for bone or soft tissue sarcoma of the lower extremity at UZ Leuven 18 to 95 years old Patients should be at least one year post surgery Informed consent has obtained  Exclusion Criteria:  Patients who received major prior surgery of the lower limbs or with any pathology, injury or disorder known to affect the locomotor system Skeletally immature individuals No informed consent has obtained