> ## Documentation Index
> Fetch the complete documentation index at: https://docs.uplift.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Loading Phase Lack of Shoulder Drop

> Binary indicator if the trunk does not sufficiently tilt/drop during the loading phase.

## Technical Details

* **Variable Type:** Movement Flag
* **Data Type:** Integer
* **Units:** N/A
* **Column Name:** `loading_phase_lack_shoulder_drop`
* **Optimal Direction:** Lower is better
* **Unknown Value:** -1
* **Measurement:** [Loading Phase Trunk Tilt](/biomechanics/activities/tennis/metrics/loading-phase-trunk-tilt)
* **Threshold:** Trunk tilt greater than -5°

## Description

Loading phase lack of shoulder drop is a binary indicator that flags when the trunk does not tilt sideways toward the rear (dropping the dominant shoulder) by at least 5° during the loading phase, which reduces the shoulder-over-shoulder tilt used to load the serve.

## Use Cases

* Loading posture assessment
* Mechanics evaluation