Answers to the questions people actually ask, and a way to reach a human.
Usually nothing is wrong yet — but there are three things worth checking, in this order.
1. Is your height entered in Apple Health? Walking speed and step length are calculated from your height. Without it, your iPhone cannot produce either one, no matter how much you walk. Open Health → Browse → Body Measurements → Height.
2. Where do you carry your phone? Apple only measures how you walk when the iPhone is carried close to your body — a trouser pocket or a waist holder. In a bag, a coat pocket, or your hand, it records nothing at all. This is Apple's rule, not ours, and there is no way for an app to work around it.
3. Can Truestride read the data? Apple Health asks permission for each measurement separately, and every switch starts turned off. It is easy to tap past that screen, and iOS only ever asks once. Check in Health → tap your picture → Privacy → Apps → Truestride, and switch everything on.
After that, give it about a week of ordinary walking. Walking asymmetry in particular needs several days before Apple will report anything.
Your own walking from before the operation appears straight away, if Apple Health recorded any. Measurements from after surgery usually start arriving once you are walking regularly enough for your iPhone to pick it up — often around two to three weeks, sometimes longer. Truestride does not compare you to anything before week two, because the first fortnight is too unsettled for a comparison to mean much.
Because the measurement isn't precise enough to say. Apple's own stated accuracy for double support is about ±3 percentage points, and the entire published change after a knee replacement is under 1.5 points. The error is wider than the thing being measured, so a weekly verdict there would be noise dressed up as a finding. We show the number and your trend, and stop short of ranking it.
The recovery curve Truestride compares against comes from a published study of 686 total knee replacement patients. No equivalent published dataset exists for hips or partial knees, so those users get their own numbers, their full history, and chart sharing — but no comparison, because there is nothing honest to compare against. We would rather say that than borrow a curve that doesn't apply to you.
No. There isn't one. Truestride has no sign-up, no login, no password, and no server. Nothing about you leaves your iPhone.
Open Settings inside the app and tap Restore purchase. It's a one-time purchase tied to your Apple ID, so it comes back on any iPhone signed in to the same account. If it says no purchase was found, check you are signed in with the same Apple ID you bought it with.
No. It's a single payment. Nothing renews and there is nothing to cancel.
Settings → Start over erases your surgery details and your saved knee measurements from the phone. Deleting the app removes everything it stores. Your Apple Health data is yours and is never touched by either.
Truestride measures the angle of your thigh and your shin using your iPhone's motion sensors and takes the difference — the same method a physiotherapist uses with a goniometer. Each reading is averaged over three seconds and discarded if the phone moves, so the numbers are repeatable. Take them to your surgeon or physiotherapist rather than acting on them alone.
Bugs, confusing wording, a measurement that looks wrong, or an idea for the app — email the address at the top. Screenshots help enormously. Please include your iPhone model and iOS version if something isn't working.
Truestride is not a medical device and does not provide medical advice. It describes measurements your iPhone already records and compares them with published averages. Talk to your surgeon or physiotherapist about your recovery.