Support
We're here to help you get the most out of Strength IO.
Have a question, feature request, or found a bug? We'd love to hear from you.
StrengthIO@crimson-io.comFrequently asked questions
How does recovery tracking work?
Strength IO reads up to seven recovery signals from Apple Health — heart-rate variability, sleep, resting heart rate, respiratory rate, blood oxygen, wrist temperature, and heart-rate recovery — alongside your training history, to estimate how recovered each of your muscle groups is. Recovery and readiness update automatically as new health data becomes available.
Do I need an Apple Watch?
No, an Apple Watch is not required. However, if you have one, Strength IO can access additional health metrics like HRV and provide live heart rate during workouts. The app works great with just iPhone health data too.
Is my data secure?
Yes. Your account and workout data are stored on secure, encrypted servers and tied to your Strength IO account, and you sign in with Apple or email. Your raw HealthKit data — individual heart-rate samples, sleep readings, HRV time-series — is processed on your device and never uploaded. Strength IO's AI coaching also runs entirely on your device. We never sell your data, never use advertising, and never send your data to any third-party AI. See our Privacy Policy for full details.
Does it really use my runs and rides from other apps?
Yes. Any workout that lands in Apple Health — a run in Strava, a ride in Apple Fitness, a class on Peloton — is read by Strength IO and factored into your recovery and readiness. A hard cardio day quietly tones down the next day's lifting intensity. You don't have to log anything in Strength IO for this to work.
How do I set up my equipment?
Go to Settings → Gym Profiles. You can create multiple profiles (like "Home Gym" and "Commercial Gym") with different equipment selections. When generating workouts, Strength IO will only suggest exercises you can actually perform with your available equipment.
What is the volume target range?
Every muscle group has a minimum number of weekly sets needed to stimulate growth, and a maximum you can do while still recovering. Strength IO tracks your volume and shows whether you're below, within, or above this target range for each muscle group.
What happens to my data if I get a new phone?
Your workout history, PRs, and preferences are tied to your Strength IO account and backed up to our secure servers. Sign in on your new iPhone and everything restores automatically. Your Apple Watch stays in sync with your iPhone during workouts.
How accurate is the 1RM estimation?
Strength IO uses a validated submaximal-load formula to estimate your one-rep max from everyday working sets. It's most accurate for sets of ten reps or fewer and gives you a reliable benchmark without risky maximal attempts.