TestFlight beta · iPhone · United States

Join the TeraThreshold beta

TeraThreshold is in beta on TestFlight, Apple's app for trying iPhone apps before they reach the App Store. Leave your email and Apple sends you an invite. Install it, sign in with your Garmin account, and every run is scored for running form and injury risk against your own baseline.

  • An iPhone with iOS 17 or later.
  • A Garmin watch that syncs to Garmin Connect. Ground contact time, vertical oscillation, stride length and balance need a watch that records running dynamics, or an HRM-Pro strap or Running Dynamics Pod.
  • The United States. The beta is open to runners in the US.

Request an invite

Apple emails the TestFlight invitation to this address.

We share this address with Apple only to send the invite. Privacy Policy

Invites go out once the current beta build clears Apple's TestFlight review. Request now and Apple emails you as soon as it does.

How to join

About five minutes on your iPhone, once the invite arrives.

  1. Request an invite

    Enter your email above. Apple sends the TestFlight invitation to that address.

  2. Install TestFlight

    Get TestFlight, Apple's free app for beta testing, from the App Store on your iPhone.

  3. Accept the invite

    Open the email on your iPhone, tap View in TestFlight, then install TeraThreshold.

  4. Sign in with Garmin

    Open TeraThreshold and tap Continue with Garmin. Your runs arrive after your watch syncs.

During the beta

Does the beta cost anything?

No. Every new account starts with 30 days of Pro, and purchases made in a TestFlight build are never charged.

How do I send feedback?

Take a screenshot in the app and tap Share Beta Feedback, or open TestFlight and tap Send Beta Feedback. You can also email [email protected].

How long does a beta build last?

Each TestFlight build works for 90 days. With automatic updates on, TestFlight installs new builds for you as they arrive.

I requested an invite but nothing arrived.

Check your spam folder first. If the current build is still in Apple's review, the invite arrives when it is approved. Otherwise email [email protected].

Can I leave the beta?

Yes. Tap Stop Testing in TestFlight, or delete the app. To delete your data as well, delete your account in the app's Settings first; everything is removed after a 30-day window.

What does TeraThreshold do?

It scores every Garmin run for running form and injury risk against your own baseline, and keeps your Race Fitness, paces and heart-rate zones current. See the full tour.