Thresholds

FitRepo tracks your physiological thresholds historically so that TSS calculations and fitness analysis remain accurate as your fitness changes.

Metrics

Metric key	Description	Unit
ftp	Functional Threshold Power	watts
lthr	Lactate Threshold Heart Rate	bpm

Schema

Column	Type	Description
id	UUID	Row identifier
user_id	UUID	Owner
metric	text	ftp or lthr
value	real	Threshold value
effective_from	date	Date from which this value applies
source	text	auto or manual
notes	text	Optional free-text note
created_at	timestamptz	When the record was created

Each (user_id, metric, effective_from) combination is unique. You can have multiple FTP values over time, each with a different effective_from date.

Sources

auto — detected automatically

When an activity is processed, FitRepo checks whether the 20-minute best effort exceeds 95% of your current FTP (a common FTP proxy). If so, a new threshold row is written automatically with source = 'auto'.

Auto-detection is conservative — it only writes a new entry if the detected value is meaningfully higher than the current FTP, preventing noise from atypical efforts.

manual — set by you

You can set your FTP and LTHR manually in Settings → Thresholds. Manual entries always take precedence over auto-detected ones for the same effective_from date.

How FTP is applied to TSS

When computing TSS for a historical activity, FitRepo finds the FTP row where effective_from is the most recent date ≤ the activity’s started_at. This means:

• Old activities use the FTP that was correct at the time.
• Updating your FTP today doesn’t retroactively change historical TSS.
• Your CTL/ATL history is stable.

Querying via MCP

Use the get_thresholds tool:

# All FTP history
get_thresholds(metric: "ftp")

# LTHR history for a period
get_thresholds(metric: "lthr", from: "2024-01-01", to: "2025-01-01")

# All thresholds, all time
get_thresholds()

Example response

[
  {
    "metric": "ftp",
    "value": 265,
    "effective_from": "2025-01-15",
    "source": "auto",
    "notes": null
  },
  {
    "metric": "ftp",
    "value": 258,
    "effective_from": "2024-09-01",
    "source": "manual",
    "notes": "Post-summer ramp test"
  }
]