Independent studios
One coach, an assistant or two, and a steady weekly schedule. C3NTR puts your programming, technique and recovery notes in one place. No second tool, no spreadsheet.
For fitness schools
A knowledge home for your HIIT studio.
Intervals, intensity, recovery and the work between rounds
→ See a quick tour
Free for up to 30 students
No credit card
UK GDPR · EU (London)
Works offline
Your studio's programming deserves a home
Work-rest ratios get called out in class but rarely written. Movement scaling varies by instructor. Recovery protocols live in the instructor's head. C3NTR is a quiet place to write it all down once, in your studio's voice.
Who this is for
Studios with multiple coachs
Two or more coachs, several classes a week. C3NTR holds the shared standard so every session draws from the same library.
Studios with sport-specific HIIT
You program HIIT for runners, cyclists or team athletes. Content locked by level keeps newer members safe while advanced see sport-specific work.
Built for teachers, not for IT
Your coach opens the app, taps Edit, and writes the next interval ratio note in plain prose. The next class, members know the ratio before they start.
Write directly in the app
Like a notepad. New articles are drafts until you publish, so nothing goes live by mistake.
Mobile-first authoring
Edit on the phone between classes or on the way home. The same library, the same edit screen.
A working library in under an hour
Import the starter template in a few taps. Edit anything that doesn't fit. Publish when ready.
Levels, beginner, intermediate, advanced
Content locked by level, in your studio's progression
Tag any article with a minimum level. Beginners see foundations and scaling. Intermediate see longer intervals. Advanced see full conditioning. The same library, the right view per member.
A glossary of HIIT terminology
HIIT has its own movement vocabulary. C3NTR's glossary holds the terms in one place: the exercise names, your studio's preferred cues, and the article each term appears in.
- Interval
- A defined period of effort followed by a defined period of rest or reduced effort. The alternation between the two is the core structure of all HIIT training.
- Tabata
- A specific interval format..
- Work:rest ratio
- The relationship between the duration of a work interval and the duration of the following rest..
- EMOM
- Every Minute On the Minute. At the start of each minute, you perform a set number of reps. The remaining time in that minute is your rest before the next minute begins.
- AMRAP
- As Many Rounds As Possible..
- Circuit
- A sequence of two or more exercises performed one after the other with minimal rest between them, then repeated for a set number of rounds.
Class series, conditioning blocks, studio closures
C3NTR isn't only the library. Schedule the next class series, post conditioning blocks, and let members see what's ahead. Announcements land on their Today tab and events sit on the calendar.
Start from our HIIT template
A working starter with 15 articles, 2 short videos, a 8-terms glossary across 5 tags (Getting Started, Foundations, Practice, Progression, Resources). Import in a few taps, then edit anything that doesn't fit your school. Every article, term and tag is yours from the moment you import.
See the HIIT template Template source:assets/templates/fitness/hiit.c3t.md
Inside the app
A look at how the library, articles and grade controls feel in your students' hands.
Plays well with what you already have
Bring your existing programming and exercise notes in with smart Word document import or paste Markdown directly from your coach's archive.
Word documents
Smart import reads headings and turns them into draft articles. You review before anything publishes.
Markdown from any editor
Notion exports, Obsidian notes, Bear, plain .md files. Paste or import.
C3NTR templates
Open .c3t.md format. Schools can share templates with each other without us in the middle.
UK GDPR · DPA 2018
UK GDPR compliant. Hosted in the EU (London).
C3NTR is built around UK data protection law from the ground up. Your school's data sits in the EU on Google Cloud London, the same region we manage from.
UK GDPR + Data Protection Act 2018
Built around UK GDPR Article 6 lawful bases. Subject access requests answered within one calendar month.
Hosted in the EU (London)
Your school's data sits on Google Cloud in the europe-west2 (London) region. No transfer outside the UK or EEA for core operation.
Encrypted in transit
All data is TLS encrypted. Access restricted to personnel with a clear business need.
Account deletion on request
Permanent deletion of personal data and content via in-app or written request.
What C3NTR is, and what it isn't
A library your school owns
Another booking or billing system
Built for how schools actually teach
A generic course builder
Calm, focused reading for students
A feed competing for attention
Start free. Move up when you outgrow it.
Seed
Free forever
Up to 30 students
All core features. No credit card.
Start freeSchool
£39/mo
£32/mo billed annually
Up to 150 students
Push notifications. 1 GB media storage.
Choose SchoolAcademy
£69/mo
£57/mo billed annually
Unlimited students
Multi-instructor publishing. Engagement analytics. 5 GB media storage.
Choose AcademyMember? Show this to your coach.
If you train at a HIIT studio and you'd love a quiet library you can return to between sessions, share this page with your coach. Most studios start on the free Seed plan in under five minutes.
Common questions
Can members only see their level's material?
Yes. Tag any article with a minimum level. Newer members see only foundations. Coaches see everything, including the deeper programming.
Does it cover Tabata, EMOM, AMRAP, your studio's programming?
Yes. The starter is method neutral. Tabata, EMOM, AMRAP can adapt the programming without rewriting.
Can my studio customise the HIIT template?
Yes. Every article, exercise and tag is editable. Add your studio's programming, your favoured progressions and your house cues.
How long does it take to set up?
Most schools have a working library in under an hour. Import the starter template in a few taps, then edit anything that doesn't fit. Starting blank takes a little longer. Allow an hour or two to write your first ten articles. Students can use the app the day you publish.
Do I have to stop using my booking system?
No. C3NTR is a knowledge library for your curriculum, terminology and progressions. Booking, billing and scheduling stay with the tools you already use.
Is there a free plan?
Yes. Seed is free forever for up to 30 students, with no credit card required. Move up to School (£39/mo) or Academy (£69/mo) when you outgrow it.
Other fitness disciplines
Teach a different style? Tell us.
Whether it's a specific HIIT lineage we don't list, or another discipline entirely, drop us a line and we'll add a starter template. In the meantime, the app already works for any structured curriculum, your library starts blank in a few minutes.
Ready to give your HIIT students a knowledge home?
Free for the first 30 students. No credit card. A working library in under an hour.
Start free for your school