> ## Documentation Index
> Fetch the complete documentation index at: https://docs.uplift.ai/llms.txt
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# Shoulder Rotation Plane Flexion

> Amount of trunk flexion required to reach the average plane of rotation of the shoulder joint centers. This measures the trunk posture for optimal swing mechanics.

## Technical Details

* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** °
* **Column Name:** `shoulder_rotation_plane_flexion`
* **Aggregation:** mean
* **Precision:** 0
* **Measurement:** Trunk flexion for shoulder plane alignment
* **Direction:** positive indicates leaning forward towards home plate
* **Typical Range:** 30 – 39 °
* **Optimal Direction:** Middle — moderate values are optimal

## Description

Shoulder rotation plane flexion measures the amount of trunk flexion needed to align with the optimal plane of shoulder rotation, indicating trunk posture for efficient shoulder mechanics.

## Normative Ranges

Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 25th–75th percentiles.

| Population         | Optimal Range (25th–75th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth              | 27 – 37 °                 |  24  |  27  |  33  |  37  |  40  |
| High School        | 27 – 37 °                 |  24  |  27  |  33  |  37  |  40  |
| College            | 29 – 37 °                 |  25  |  29  |  33  |  37  |  40  |
| Professional       | 29 – 37 °                 |  25  |  29  |  33  |  37  |  40  |
| Broad (All Levels) | 28 – 37 °                 |  24  |  28  |  33  |  37  |  40  |

## Use Cases

* Trunk posture analysis
* Shoulder mechanics assessment
* Plane alignment evaluation
* Technique optimization