Cycling workouts in watts on Garmin, indoors and on the road
On a bike, power has replaced everything else: it does not lie about wind, gradient or fatigue. You still have to express it the way Garmin expects. Here is how to build a structured cycling workout, indoors and out.
Last updated: 2026-08-24
Why power rather than speed
On a bike, speed depends on almost everything except your effort: a two percent gradient, a headwind or a wet road can halve it at constant effort. Power measures directly what you produce.
That is why a structured cycling workout is driven in watts whenever a meter is available, and by heart rate otherwise — accepting that the cardiac response lags at the start of short efforts.
What Garmin accepts as a cycling target
Cycling vocabulary differs from running, and that is a frequent source of error when transposing a session between sports.
- Power in absolute watts, with a low and high bound. That means a number of watts, not a percentage.
- Percentage of maximum heart rate, useful without a power meter or on long rides.
- Cadence in revolutions per minute, often combined with a power target for leg-speed or force work.
- The open step, with no target, for a free warm-up or a cool-down.
Classic mistake: sending a power target as a percentage of FTP. Garmin expects absolute watts. Convert before sending, or the target is read wrongly and the workout steers nothing.
One session can alternate: power on the intervals, cadence on the drills, nothing at all on recovery.
FTP, zones and common sessions
FTP is the power you could hold for roughly an hour. It anchors the zones, and is worth reassessing every two to three months.
- Endurance, around 60 to 75% of FTP: the volume that builds the base, at little recovery cost.
- Tempo and threshold, 76 to 105%: the core of useful work, in blocks of eight to twenty minutes.
- VO2 max, 106 to 120%, in three to five minute reps: expensive, to be dosed.
- Sprints, beyond that, over tens of seconds, where a power target loses meaning next to simply going maximal.
A decent FTP estimate comes from a maximal twenty-minute effort, keeping about 95% of the average power.
Indoors: what changes
Indoors, the structured workout comes into its own: no traffic lights, no descents, the target power is holdable to the second. A controllable trainer can even impose the resistance needed to keep you on target without any adjustment from you.
One detail distorts many comparisons though: activities recorded on a virtual training platform do not always come back through Garmin's official channels. The session may have happened without the data reaching your tracking.
Frequently asked questions
Do I need a power meter for a structured workout?
No, but without one the target has to be heart rate. That is acceptable on long efforts and much less so on short intervals, where the heart takes over a minute to reflect the real effort.
How do I convert a percentage of FTP into watts?
Multiply your FTP by the percentage: 90% of a 250 W FTP is 225 W. That watt figure is what Garmin needs, never the percentage.
Are indoor and outdoor cycling handled differently?
The workout structure is identical. The difference is practical: outdoors, power targets are harder to hold, and widening the ranges is usually wise.
How often should I retest FTP?
Every two to three months is enough, or after a marked training block. An overestimated FTP makes every session too hard and distorts load tracking at the same time.
Let your assistant write your sessions
Running Workout connects Claude, ChatGPT or Gemini to your Garmin account through the official API. Nothing to install, and no Garmin password to hand over.
See the connection guide