Your Forerunner 255 tracks HRV, sleep, and Body Battery every night. Forma turns that data into a structured strength session every morning.
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The gap
The Forerunner 255 delivers legitimate biometric intelligence: HRV status, Body Battery, sleep score, and training load ratio. These signals, taken together, tell you something meaningful about whether your body can handle heavy compound lifts today — or whether it needs something lighter.
But the watch does not tell you what to do in the gym. Garmin's strength training features are not available on the 255. Most 255 owners either ignore their recovery data entirely, or guess at the relationship between a Body Battery score and their deadlift volume.
Neither approach is optimal. Forma closes the gap.
The engine
Forma's readiness engine processes five inputs each morning:
| Input | What it reflects | How Forma uses it |
|---|---|---|
| HRV status | Autonomic nervous system readiness | Primary session tier signal |
| Body Battery | Overall energy reserve (0–100) | Session type threshold |
| Sleep score | Recovery quality last night | Modifies intensity and volume |
| Training load ratio | Recent vs chronic training stress | Overtraining detection |
| HRV low streak | Days of consecutive suppressed HRV | Protective downgrade trigger |
The engine maps these five signals to a readiness tier (R1–R4) and session type (S1–S5). The session type determines the workout: exercise selection, sets, reps, rest intervals, and coaching cues. The full workout is available in the web app or pushed directly to your Garmin watch.
Compatibility
Forma uses four biometric signals from your Garmin device. The Forerunner 255 tracks all of them. Training Readiness is not required — Forma calculates its own readiness assessment from the signals below.
| Metric | Available on Forerunner 255 | How Forma uses it |
|---|---|---|
| HRV status | Yes | Primary readiness signal — drives session tier |
| Body Battery | Yes | Energy reserve — threshold for heavy vs light session |
| Sleep score | Yes | Recovery quality — modifies session intensity |
| Training load ratio | Yes (Training Status required) | Overtraining detection — prevents repeated high-load days |
| Training Readiness | Not available | Not required — Forma builds its own readiness assessment |
Device coverage
Strength Coach is not available on the Forerunner 255. Forma fills that gap today — and it doesn't require Training Readiness, so the 255 is a fully supported device with no missing features.
Forma works on 27 Garmin devices. You connect your Garmin account once, and Forma auto-fetches your recovery metrics before each session. The workout is ready before you reach the gym.
Concrete example
Your Forerunner 255 shows Body Battery 68, HRV Balanced, and sleep score 74. Your training load ratio is 1.05.
Forma's engine processes all four signals and prescribes S2 — Moderate Strength. That session includes a warm-up, primary compound movements, accessory exercises, and a cool-down. Every step has coaching cues. The full workout is available in the web app or pushed directly to your watch.
If your Body Battery were 30 and your HRV low, the same morning would produce a lighter session — Conditioning or Active Recovery — because the engine reflects your actual state, not a fixed plan.
Session types
Forma selects one of five session types each morning. You do not choose — your biometric data does.
Get started
Enter your metrics manually or connect your Garmin account. Your first workout is ready in seconds.
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Common questions
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