Measurement
Photogrammetry, goniometry, inertial sensors, and their limits.
5 guides · updated 4 Oct 2026 · every claim sourced
Posture biofeedback: the evidence
Posture reminders and wearables improve posture while they are on. Whether the change lasts, what trials found for pain, and how to use feedback well.
3 min read · Limited evidenceMeasureIMU sensors
An IMU combines an accelerometer and a gyroscope to work out how a body part is tilted. How these motion sensors measure posture and how accurate they are.
3 min read · Limited evidenceMeasurePosture tracking with AirPods
AirPods with head tracking report head angle. How posture tracking from earbuds works, how accurate head sensors are in studies, and what it cannot measure.
4 min read · Limited evidenceMore in Measurement
Your personal baseline
Healthy posture varies widely, so a tracker should compare you with your own upright, not a textbook ideal. How a personal baseline works and why it is fairer.
3 min readHow-toHow posture is measured
Posture can be measured with photos, angle tools, X-rays, lab motion capture and wearables. How accurate each is, and what wearable sensors cannot measure.
3 min readAbout this topic
Posture can be measured with photos, angle tools, wearable sensors and, more recently, the motion sensors inside headphones. This section explains how each method works and how accurate it is, including how AirPods and other earbuds report head angle, what an inertial sensor (IMU) measures, and why a personal baseline beats a textbook ideal. It also defines the measures BodySignals uses, such as posture drift, time away from your baseline, time to correct and the Body score, and states where they are product settings rather than clinical thresholds. If you want to know what a number on a posture tracker actually means, or whether posture reminders and biofeedback change anything, start here.
- Strong consistent results from trials and reviews
- Moderate good studies, some gaps
- Limited few or small studies
Coming soon
Guides we are writing for this topic.