Crescendo 4×4
Norwegian HIIT starting at 30 seconds, scaling to the full 4×4 protocol
A guided high-intensity interval training app that progressively builds VO₂max through Norwegian 4×4 workouts, starting with short 30-second intervals and
About the business
Crescendo 4×4 guides users through the Norwegian 4×4 high-intensity interval protocol with a progressive on-ramp that begins with 30-second work intervals and climbs to the full 4-minute intervals over time. The app features voice-guided coaching throughout each session, including warm-up, work intervals, recovery phases, and cool-down, and works with the screen locked and music playing.
The app integrates with Apple Watch for native workouts with personalized heart-rate targets, and optionally saves sessions to Apple Health. It automatically computes personal heart-rate zones from your maximum heart rate and includes an adaptive progression system that levels up based on your performance and recovery data, without shame mechanics or forced streaks.
Crescendo prioritizes privacy: there is no account, no ads, and no tracking. The app is available in four languages (English, Polish, German, and Spanish) and provides access to educational guides explaining the Norwegian 4×4 protocol, beginner progression strategies, and heart-rate zone fundamentals.
What you get
- Progressive on-ramp starting at 30-second intervals
- Voice-guided coaching throughout entire session
- Lock Screen and Dynamic Island display (iOS 17+)
- Works with screen locked and music playing
- Available in four languages
- Personalized heart-rate zones computed from max heart rate
- Native Apple Watch Workout app integration
- Adaptive level progression based on recovery data
- No account, no ads, no tracking
Pricing
Pricing model: Free
Neighbours ask
What is the Norwegian 4×4 workout?
The Norwegian 4×4 is a high-intensity interval protocol from NTNU in Norway consisting of four 4-minute work intervals at 85–95% of maximum heart rate, each followed by 3 minutes of easy recovery, plus warm-up and cool-down totaling about 40 minutes. It is the most-studied HIIT protocol for improving VO₂max, with research showing gains of roughly 7–10% in eight weeks.
Is the Norwegian 4×4 suitable for beginners?
The full protocol is not a beginner workout, but Crescendo 4×4 exists to bridge this gap with a progressive couch-to-4×4 on-ramp that scales the structure down beautifully, starting with 1-minute work intervals and building over six to ten weeks.
How often should I do Norwegian 4×4 workouts?
Twice a week, at least 48 hours apart, for eight weeks is the researched dose behind VO₂max results. More hard sessions is not better; adaptations happen during recovery, and additional weekly 4×4 sessions typically degrade quality before adding fitness.
Does Crescendo 4×4 work with Apple Watch and Apple Health?
Yes, optionally. You can send your current on-ramp level to a paired Apple Watch as a native workout with personal heart-rate range alerts on work intervals, and completed phone sessions can be written to Apple Health. Both are opt-in and the app is fully usable without either.
Does Crescendo 4×4 work with a locked screen and music?
Yes. Every session is voice-coached with interval starts, halfway calls, recoveries, and countdowns that work with your iPhone locked in a pocket or armband. Music ducks briefly under each cue and comes right back. On iOS 17+, Live Activities and the Dynamic Island show your live phase, interval count, target heart-rate zone, and countdown on your Lock Screen.
Leave a review for Crescendo 4×4
No one has reviewed Crescendo 4×4 yet. Say something first. Reviews are free. A business can't pay for them.
Crescendo 4×4 has a free listing. The owner can unlock the full profile with a paid launch for $5:
- Founder story (locked)
- Milestones (locked)
- Demo video (locked)
- Dofollow website link (locked)
Also opened nearby
MyFitTrainingPlanFitness apps
RepolveFitness apps
BodyBenchFitness apps
2fit4uFitness apps