Chiron is a training log built around the relationship between a coach and an athlete.

Build a program once and follow it: every workout, every set, every week. Chiron shows you what you lifted last time, right beside the input, so you always know what to beat. Supersets, exercise alternatives, coach notes and a rest timer are all where you need them, in the middle of a set — not buried in a menu.

IF YOU COACH
Send an athlete an invite code and you get a roster. Build their program, schedule their week, then follow how it actually goes: which sessions they completed, what they lifted, how hard it felt, and the notes they left you. Comment on a session and they see it in their inbox. Everything works on your phone or on a full-sized screen in a browser.

IF YOU TRAIN
You get a plan that tells you exactly what to do today, and a record of everything you have ever done. Track bodyweight and measurements across eight sites, set goals with real targets, and see your strength trends per exercise.

WHAT'S INSIDE
• 870+ exercises with images, plus your own custom movements
• Programs with supersets, rep ranges, target weights and coach-picked alternatives when a machine is taken
• A session logger that shows your previous result on every set
• Rest timer, RPE, and notes — to your coach or private to you
• Bodyweight, measurements, goals and a daily calorie limit
• Strength trends, streaks and personal-record detection
• Coach tools: roster, invite codes, assignment, compliance and session review
• A two-way thread on any session, collapsed until you open it
• Works in kilograms or pounds

HEALTH CONNECT
Optional, and off until you switch it on. Chiron can write a finished workout into Health Connect, sync bodyweight both ways, and show your daily steps against a goal. Reading your weight and writing your workouts are separate switches, because they are different consents. The app works fully without any of them.

Chiron is free. There are no ads, no subscriptions, and nothing is sold.