Gait velocity and stride length are critical health indicators for older adults. A decade of medical research shows that they provide a predictor of future falls, hospitalization, and functional decline among seniors. However, currently these metrics are measured only occasionally during medical visits. Such infrequent measurements hamper the opportunity to detect changes and intervene early in the impairment process.

Understanding users’ behavior at home is central to behavioral research. For example, social researchers are interested in studying domestic abuse, and healthcare professionals are interested in caregiver-patient interaction. Today, such studies rely on diaries and questionnaires, which are subjective, erroneous, and hard to sustain in longitudinal studies

FSHD is a rare, slowly progressive myopathy characterized by weakness initially in facial, shoulder, and upper limb muscles followed by abdominal and paraspinal weakness, and finally lower extremity weakness. FSHD affects between 16,000–38,000 people in the US, and its symptoms often progress over decades, creating significant challenges in tracking disease progression using in-clinic scales and functional tests.