Strength IO: Workout Tracker
Intelligent strength training
About
This app intelligently adapts your strength training sessions based on your daily recovery signals and logged activities from other apps. It analyzes multiple health metrics to determine optimal workout intensity, preventing overtraining and maximizing gains. Track your progress with detailed athlete profiles and personalized insights.
What's New in Strength IO
1.09
September 15, 2026
Strength IO is ready for iOS 27, and it now has an AI coach built on Apple Intelligence. AI COACH • Readiness overview: your coach reads your vitals, sleep and training and tells you where you stand today. • Training load insight: understand what your last 7 days mean for your body. • Powered by Apple Intelligence, on your iPhone or on Apple's Private Cloud Compute. NEW READINESS SCREEN • See exactly what's lowering or raising your score. NEW TRAINING LOAD • A load card and chart right at the top of the Training tab. iOS 27 • Heart-rate zones come straight from your Apple Watch. • Ask Siri what to train today, and start it right away.
MoreSubscription plans
Strength IO Pro
Strength IO Pro Monthly
Developer apps
FAQ
What is Strength IO?
Strength IO is an intelligent strength training app that personalizes your workouts based on your body's recovery signals and logged activities from other apps. It aims to help you train smarter by adjusting intensity and volume to prevent overtraining and optimize muscle growth.
How does Strength IO determine workout intensity?
Strength IO uses seven key health signals, including HRV, sleep, resting heart rate, and more, to estimate your daily readiness. It then anchors your workout weights to your real effort and per-muscle recovery, making sessions heavier when you're fresh and lighter when you're not.
Does Strength IO work with other fitness apps?
Yes, Strength IO integrates with Apple Health to read your logged activities from other apps like Strava, Peloton, and Apple Fitness. This allows it to adjust your lifting sessions without requiring you to double-log your workouts.
What kind of data does Strength IO track for athlete profiles?
Strength IO builds a comprehensive athlete profile that includes a Strength Score for every muscle group, rolled up by push, pull, and legs. It also tracks VO₂max, resting heart rate, heart-rate recovery, and cardio efficiency trends over time.
Is Strength IO private?
Yes, Strength IO is private by default. The coaching and analysis run on your device, ensuring that your personal data stays with you.
What are the subscription options for Strength IO Pro?
Strength IO offers a free trial of the full app. After the trial, you can choose a monthly subscription for $9.99 or a yearly subscription for $59.99 to keep all features unlocked. Both plans include a 7-day free trial.
How do I cancel my Strength IO Pro subscription?
Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period. You can manage or cancel your subscription anytime through your App Store account settings.
What devices is Strength IO available on?
Strength IO is available for iPhone and Apple Watch, providing a seamless experience for tracking your workouts and recovery.