Step Doctor is now fully released on iPhone and Android. After a period of open testing, the app is out of testing and available to everyone in English and Korean: three standard tests of mobility and balance, run and scored from one phone video.
Download on the App Store · Get it on Google Play
Three tests, one phone
- Gait analysis. Walk toward your phone for a few seconds and get your walking speed, cadence, step length, step timing, left–right balance and a 0–100 gait score. More about gait analysis.
- Instrumented Timed Up and Go (iTUG). Stand up, walk, turn, come back and sit. Step Doctor times the whole test and each of its six phases, and grades every phase against published reference values. More about the iTUG.
- SPPB. The Short Physical Performance Battery: balance, a 4-metre walk and five chair stands, scored 0–12 with the standard cut-offs. More about the SPPB.
What's in every result
- Voice-guided, hands-free. Spoken instructions in English or Korean walk you through the iTUG and SPPB, so you can record yourself without help.
- Just your phone. No sensors, wearables or lab. Stand the phone up, calibrate the camera once and walk.
- 3D replay. Watch every result move in 3D: your walk, each iTUG phase, each SPPB balance stance.
- PDF report. A report for each test, ready to share with your therapist or family.
- AI coach. Ask about your results in plain language and get answers grounded in your numbers.
- Exercises for you. A fresh mix of exercises after every result, led by what needs the most work.
- Progress over time. Trends for every test in one place, so you can see what changes.
Analysis takes under 10 seconds after the video is uploaded.
See the tests in action
Real tests from Step Doctor, replayed on the app's 3D avatar (no faces are shown). First, an SPPB that scored 11 of 12:
More clips in our guides to gait analysis, the Timed Up and Go and the SPPB.
Built on published research
Every result is judged against the research behind the test: gait speed thresholds, age norms for the TUG, iTUG phase reference values and the NIA's SPPB cut-points. Our scientific overview explains how the measurements are made and what has been validated so far, and the reference values page lists every threshold with its source.
Private by design
Videos and results are encrypted in transit and at rest. Videos are used only to produce your results and are deleted from our servers after about 72 hours. Results are never sold or used for advertising. AICU's quality management system is certified to ISO 13485:2016.
Pricing
Step Doctor is free to download. Each test uses credits, and new accounts get welcome credits to try the tests.
Who it's for
- Older adults and families who want to keep an eye on mobility and balance at home, between visits.
- Physiotherapists, rehabilitation teams and falls clinics who want repeatable, recorded measures without wearable sensors.
- Care homes and researchers who repeat standard tests over time.
Thank you to everyone who tested Step Doctor and sent us feedback. Questions or partnership requests: contact us.
Step Doctor supports screening and monitoring. It doesn't diagnose, and results should inform, not replace, the judgement of a healthcare professional.
