# Study 000F Results

## Summary

This study supports a strong hypothesis answer:

`the archive supports a successful operating envelope as a better explanatory construct than surface category alone`

## 1. Success clustering supports envelope formation

The later archive does not look like broad environmental normalization.
It looks like narrowed successful expression clustering into a compact operating region.

- `P5` mean running share: `87.90%`
- `P5` treadmill running share: `98.33%`
- late QC window running share range: `50.58%` to `62.61%`
- late QC window mean HR residual burden: `3.09 bpm`

That is the first operating-envelope signal:
successful expression is clustering, not broadening indiscriminately.

## 2. Burden boundary behavior supports a meaningful envelope edge

The October 2025 outside-context cluster was not just outdoor.
It was outdoor with thin stabilized embedding and very low running-share support.

- October 2025 outside-cluster mean running share: `5.13%`
- October 2025 outside-cluster mean treadmill neighbors: `1.75`
- October 2025 outside-cluster mean HR residual burden: `13.88 bpm`

That burden level is materially above the late successful cluster.

## 3. The April 2026 exception strengthens the model instead of breaking it

`2026-04-09` is the key boundary-expression case.

It showed:

- outside-context mechanics
- but only `0.69 bpm` HR residual burden
- `91.08%` running-share embedding
- `32` treadmill neighbors within `21` days
- `-3.35` bpm versus matched treadmill mean HR

That means surface departure did not automatically force high burden.
This is exactly where `operating envelope` outperforms `surface category`.

## 4. Surface category alone is too weak

Across all outdoor runs in the archive:

- HR residual burden ranged from `-3.75` to `32.84 bpm`
- the same outdoor label contained both strongly positive and near-zero burden states

So the study does not support:

`outdoor = outside successful expression in every meaningful sense`

It supports:

`surface is one input into a broader operating envelope`

## 5. Strongest answer

The strongest answer from this package is:

`000D` and `000E` together are better explained by a successful operating envelope than by a simple treadmill-versus-outdoor distinction.