Smartphone videos of the sit-to-stand test predict osteoarthritis and health outcomes in a nationwide study

Physical function decline due to aging or disease can be assessed with quantitative motion analysis, but this currently requires expensive laboratory equipment. We introduce a self-guided quantitative motion analysis of the widely used five-repetition sit-to-stand test using a smartphone. Across 35 US states, 405 participants recorded a video performing the test in their homes. We found that the quantitative movement parameters extracted from the smartphone videos were related to a diagnosis of osteoarthritis, physical and mental health, body mass index, age, and ethnicity and race. Our findings demonstrate that at-home movement analysis goes beyond established clinical metrics to provide objective and inexpensive digital outcome metrics for nationwide studies.

Automated summary

A self-guided quantitative motion analysis using a smartphone has been introduced to assess physical function decline caused by aging or disease, which currently relies on expensive laboratory equipment. In a study involving 405 participants from 35 US states, videos of the participants performing the five-repetition sit-to-stand test in their homes were recorded. The quantitative movement parameters extracted from the smartphone videos were found to be related to osteoarthritis diagnosis, physical and mental health, body mass index, age, and ethnicity and race. These findings highlight the potential of at-home movement analysis to provide objective and cost-effective digital outcome metrics for nationwide studies.