Inclusion Criteria:  Men and women aged 18 to 65 years old. Able to walk independently or with assistance (human/walking aids). Able to speak and read fluently in Hebrew. Admitted for rehabilitation at a rehabilitation hospital day-care center following lower-extremity disability or chronic pain (unilateral or bilateral). Have undergone at least 4 weeks of rehabilitation, but require an additional (at least one month long) rehabilitation course. Subjects must be willing to use their own smartphone device to install the OneStep application for study procedures and to comply with the study protocol. The subjects' smartphone has to be compatible with the OneStep app hardware requirements.  Exclusion Criteria:  Subject unable to step on the sore foot. Subject unfit to participate in the study based on the judgment of the study principal investigator. Subjects who are permanently wheelchair-bound. Subjects with known pregnancy.