Privacy Policy
Last updated: 23 October 2026
Yield Strength is a strength-training app with an AI coach, made by Northline Standard LLC ("we", "us"). This policy explains what data the app collects, why, who else sees it, and how to get rid of it. It covers the Yield Strength iOS app and this website.
The short version. We collect the training you log, the profile you tell us about, and — only if you allow it — recovery and body data from Apple Health. We use it to coach you. We share it with a small number of service providers who help run the app, including an AI provider that generates the coaching text. We do not use it for advertising. You can delete your account and everything in it from inside the app at any time.
What we collect
Account information
When you sign in we store your email address and an account identifier. If you use Sign in with Apple and choose to hide your email, we only ever receive Apple's private relay address, not your real one. We never see or store a password — sign-in is either a one-time code sent to your email or Sign in with Apple.
Training data
The substance of the app: workouts and the sets inside them (exercise, weight, reps, and reps-in-reserve where you record it), training blocks and their weekly targets, personal records, the progression recommendations you were shown and whether you accepted or overrode them, session scores, and any notes or workout names.
Profile and equipment
What you tell us about yourself so the coaching is calibrated: your training goal, how long you've been training, body weight, height, birth year, sex, how many days a week you train, and the equipment you have access to. All of it is optional.
Apple Health data — only with your permission
If you allow Health access, Yield Strength reads the following from Apple Health:
- Sleep, heart rate variability, resting heart rate, wrist temperature and body temperature, to show how recovered you are
- Workouts and heart rate, to count training you record in other apps and to show your heart rate during a workout
- Weight, body fat, lean mass and waist, to chart changes in your body over time
- Cardio fitness (VO2 max), steps and exercise minutes, to follow your fitness and daily activity
- The food and drink you log: calories, protein, carbohydrates, fat, fiber, sodium, water and alcoholic drinks, for your daily food and habit goals
- Blood pressure, on iPhone software versions that support it, so the coach can take it into account
- Height, date of birth and biological sex, to fill in your profile and work out your calorie target. From your date of birth, Yield Strength keeps only the year.
Yield Strength saves two things to Apple Health, and asks your permission before the first time:
- Waist measurements you enter in Yield Strength
- Water you log in Yield Strength
If you undo a drink straight after adding it, Yield Strength removes that entry from Apple Health. It never changes or deletes anything else there.
Yield Strength saves nothing else to Apple Health. Health access is entirely optional, the app works fully without it, and you can switch it off at any time under Profile → Apple Health or revoke it in Apple's Health app. We never sell Health data, and we never use it for advertising or marketing.
Health questions before you start
Before you start training, Yield Strength asks eight short yes-or-no health questions, the kind a gym or trainer asks, such as about your heart, chest pain, fainting, medication and joints. Your answers are stored in your own account, only you can see them, and they are deleted when you delete your account. We never send them to analytics, and we use them for nothing except deciding whether to suggest a doctor's check. If a check is advised, the coach is told that and nothing else. When your answers suggest checking with a doctor, we keep a record that you saw that advice and which option you chose (start in a health pause, or continue without checking), with your account email and the time. We keep that record as evidence even after you delete your account. It never contains your answers to the questions.
Conversations with the coach
What you say to the coach and what it says back, so the conversation persists and the coaching stays consistent with your training. If you set a pregnancy pause, the coach is told, so it can step back from training advice.
Notifications
If you allow notifications, we store the notification token that Apple gives your device, linked to your account, so we can send them to you. It is deleted with your account.
Usage analytics
To build the best app we can, we pay close attention to how Yield Strength is actually used — both in the app and on this website. We record what you do and how you move through it: the screens and pages you visit, the paths you take, how often and how long you use it, where you came from, and your device and rough location (derived from your IP address). On the website we also record what you tap and click, and this includes session replays and heatmaps — a reconstruction of how its pages were clicked, scrolled and moved through, so we can see where something trips people up. Session replays mask anything you type into a field. The app does not record session replays. On the website this covers visitors before they ever sign in.
What this never includes is the substance of your training. We deliberately do not send your exercise names, weights, reps, health readings, health goals, or any of your conversation with the coach to our analytics — that stays in your own account. Once you're signed in, your usage is linked to your account identifier and email address, so we can understand real behaviour over time rather than anonymous fragments. The website works the same way if you join the beta waitlist: your visits are linked to the email address you gave, and if you later sign in to the app with that address, your website visits and your app use are joined into one record. We use all of it for one thing: to understand what's working, fix what isn't, and make Yield Strength better.
Crash diagnostics
If the app crashes, it records what went wrong so we can fix it — the technical details of the failure (the type of crash and the sequence of code that led to it), plus your app version, iOS version and device model. That report is saved on your device and sent the next time you open the app. A crash report contains no training data, no health readings and no part of your conversation with the coach. It is linked to your account identifier so we can tell how many people a given crash affected and follow up if you asked us to.
Errors the app handles on its own — a sync that failed and will retry, a coach reply that timed out — are not reported as crashes.
Emails we send you
If you join the beta waitlist we send you two kinds of email, and you control them separately. Apart from the first email, which asks you to confirm your address, we send you nothing until you tap its link — including your beta invitation. Your address is also linked to your website visits in our analytics, as described under Usage analytics.
Emails about the beta. Your TestFlight invitation, notice that a new build is ready, and anything you need to know to keep testing, including if the beta ends. These are part of the thing you signed up for, so everyone who confirms gets them. If you no longer want them, ask us to remove you and we'll take you off the list entirely.
Tips and product news. Only if you ticked the box when you signed up. This covers help getting more out of Yield, and occasional news or offers about other products from Northline Standard, the company behind Yield Strength. If you didn't tick it, we will not send these.
Stopping them. Every tips-and-news email has a one-click unsubscribe — you never have to reply, sign in, or explain. We act on it right away, and within ten business days at the latest. Unsubscribing from these does not remove you from the beta or stop the emails about it.
What we keep. Your email address, when you joined, when you confirmed, and — if you ticked the box — a record of that: the date and the exact wording you were shown. We keep that record for as long as we email you and for a short period after, so we can show the permission was real. A signup that is never confirmed lapses after 30 days.
We do not sell or rent your email address, and we do not share it with other companies for their own marketing. Our email is sent for us by an email delivery provider.
Your rights. You can ask for a copy of what we hold about you, ask us to correct or delete it, or withdraw your consent at any time — withdrawing is as easy as giving it. Write to support@yieldstrength.app, or post to Northline Standard LLC, 7533 S Center View Ct #8117, West Jordan, UT 84084, United States. Northline Standard LLC is the data controller. If you're in the UK or EU and you think we've handled your data badly, you can complain to your national data protection authority.
Who else sees your data
We use a small number of service providers to run Yield Strength. They process data on our behalf, under their own terms, and are not permitted to use it for their own purposes.
| Service | What they receive | Why |
|---|---|---|
| Our database and sign-in provider | Account, training data, profile, equipment, coach conversations, your answers to the health questions, notification tokens, and Health-derived recovery snapshots if Health is enabled | Database, authentication and sync, so your training survives losing your phone and follows you across devices. Hosted in the United States. |
| Our AI provider | Your coach conversations, a summary of your recent training and profile, whether a pregnancy pause is set, and — when Health is enabled — your latest recovery and body measurements | Generating the coaching text and workout plans. This is how the AI coach works; there is no on-device alternative. |
| Our analytics provider | Usage and traffic analytics from the app and website, session replays and heatmaps from the website, crash diagnostics, your account identifier and email address, and the email address you give when you join the beta waitlist — no training content, health data, or conversation text | Product and website analytics, website session replay, and crash reporting. Hosted in the United States. |
| Redoubt Vault (a Northline Standard service) | Your email address, when you asked to join and when you confirmed, the exact wording you were shown, and when you unsubscribe. From the app, when your health questions suggest checking with a doctor: your email address, account identifier, the time, and which option you chose (start in a health pause, or continue without checking), but never your answers to the questions | Keeps the record of your permission somewhere it can't be altered after the fact, so we can show it was real if anyone asks. Hosted in the United States. |
| Our email delivery provider | Your email address and the emails we send you | Delivering our emails to your inbox. |
We choose these providers for what they do, and we may change them. Whichever provider fills a role receives only what its row says, for the reason given, and may not use it for its own purposes. If a change would alter what data leaves us, why, or where it's kept, we'll update this page and tell you before it takes effect. Ask us and we'll tell you which providers we use today.
We may also disclose data if we are legally required to, or to protect our rights or someone's safety. If Northline Standard is ever sold or merged, data may transfer as part of that — you'd be told before it happened.
Where your data is stored
Your training is stored on your device and, when you're signed in, synced to our servers in the United States. If you're outside the US, using Yield Strength means your data is transferred there.
Deleting your account and your data
You can delete your account from inside the app: Profile → Delete Account. It asks you to confirm, and then it is permanent — we cannot recover it for you afterwards.
Deleting your account removes, from our servers:
- Every workout, set and session you've logged
- Your training blocks and their weekly plans
- Your personal records and progression history
- Your profile and equipment settings
- Recovery and body measurements read from Apple Health
- Your answers to the health questions, and your notification tokens
- Any exercises you created yourself
- Your account itself
- Yield Strength's connection to your Apple ID, if you signed in with Apple
Two things we keep. Yield Strength's coach shows a notice that its guidance is coaching, not medical advice, and asks you to acknowledge it. When your health questions suggest checking with a doctor, the app also shows that advice and asks you to choose an option. We retain the record of each — that an account with your email address agreed (or, for the health advice, which option it chose: start in a health pause, or continue without checking), when, and (for the coach notice) to which version of the wording — even after the account is deleted. The record of the health advice is also held by Redoubt Vault, Northline Standard's own consent-record service. We keep them as evidence that the disclosures were made and accepted, which we have a legitimate interest in being able to demonstrate. They contain no training data, no answers to the health questions, and no conversation content.
How long we keep things
We keep your training data for as long as you have an account, because the whole point is to compare what you're lifting now against your own history. Delete your account and it goes, apart from the acknowledgment records described above. Deleting your account does not remove your usage history, or the email address linked to it, from our analytics provider, which keeps it under their retention settings. Ask us and we'll delete it there too.
Your choices
- Apple Health: optional, off until you allow it, and revocable at any time in the app or in Apple's Health app.
- Deletion: available in the app, no need to contact us.
- Access and correction: most of your data is visible in the app, and your profile and logged sets are editable there. For anything else, write to us.
- Analytics: Yield Strength does not currently offer a separate opt-out from usage analytics. If that matters to you, contact us and we'll handle it manually.
Depending on where you live you may have additional rights over your personal data. Write to us at the address below and we'll do what's required.
Security
Data is encrypted in transit. Your sign-in session is held in the iOS Keychain. On our servers, access rules are enforced per account, so one lifter's data is not readable by another. No system is perfectly secure, and we don't claim otherwise — but we keep the most sensitive things you trust us with, your training, your health readings and your conversations with the coach, out of our analytics entirely, which is the most reliable protection available.
Children
Yield Strength is for adults 18 and over. We don't knowingly collect data from anyone under 18. If you believe someone under 18 has created an account, contact us and we'll remove it.
Not medical advice
Yield Strength's coaching is training guidance, not medical advice, and it is not a substitute for a physician or other qualified professional. Lifting carries risk. Talk to a doctor before starting or changing a training programme, especially if you have an injury or a medical condition.
Changes to this policy
We may update this policy as Yield Strength grows and changes. When we do, we'll change the date at the top, and the version you're reading is always the one that applies — continuing to use Yield Strength means you're going along with it. If anything here ever raises a question for you, we'd genuinely rather hear about it than have you wonder.
Contact us
Privacy questions, requests, or anything in this policy that reads wrong to you:
support@yieldstrength.app
Northline Standard LLC
7533 S Center View Ct #8117
West Jordan, UT 84084, United States