Derny › Workouts
Workouts
A normal structured workout is a script: the targets are fixed before you start, and they stay fixed whether you slept badly or feel great. Derny’s workouts read your heart rate every second and move the target to keep the effort where the workout wants it.
Ready-made
Derny holds you at a steady heart rate well under your max and eases the effort as you tire. This is the ride that builds the engine. As your heart rate drifts up over a long session, the watts or belt speed come down to keep you in the same place.
Your warm-up shows Derny how your heart responds before three long blocks. Each block starts from what the last one taught it. It’s hard, so do it when you’re fresh.
You ride three short reps that reach up and just touch your max, with real recovery before each one. It’s very hard, so do it when you’re rested.
Which workouts appear depends on the machine you connect. Derny checks what your trainer, treadmill or elliptical can do and offers the ones it can run.
No FTP test
None of the adaptive workouts needs an FTP. They start easy and use your warm-up to find the right effort. What they do need is a heart-rate source: any standard Bluetooth strap, or an Apple Watch on iPhone.
Adaptive Endurance aims at a target heart rate worked out from your resting and max heart rate and how long you plan to ride. Here’s exactly where that number comes from, and you can move it up or down at any time.
Your own rules
If you want control, open the editor and build a workout from sections and rules. A rule says what to watch, how long it has to last, and what to do about it:
“If my heart rate goes above 160 for 10 seconds, drop the target by 5 watts, then hold for 30.”
Rules can watch heart rate, power or cadence, and change the target power, resistance or belt speed. You can also build and edit workouts by chatting with Claude or ChatGPT.
Just record
No targets and no heart-rate monitor required. You set the effort, and Derny records it. Every finished workout, adaptive or not, uploads to Strava and saves to Apple Health or Health Connect.
Questions people ask
It’s a workout where the app changes the trainer’s power, the treadmill’s speed or the elliptical’s target based on your live heart rate, instead of following targets fixed in advance. When your heart rate climbs too high, Derny lowers the target; as you recover, it builds again.
No. None of Derny’s adaptive workouts needs an FTP. They start easy and use your warm-up to find the right effort.
Yes. The workout editor lets you write rules such as “if my heart rate goes above 160 for 10 seconds, drop the target by 5 watts, then hold for 30”. You can also build workouts by chatting with Claude or ChatGPT.
Adaptive Endurance and Adaptive Threshold run on smart trainers, treadmills and ellipticals. Adaptive MAX Out runs on smart trainers and ellipticals. Derny offers the workouts your connected machine can run.
Try it
The beta is live on iPhone through TestFlight and on Android through Google Play. Your invite arrives by email.