> ## 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.

# Pelvis to Trunk Speed Up

> Ratio (multiplication factor) of speed increase from pelvis to trunk. This measures the efficiency of power transfer from the lower body to the trunk.

## Technical Details

* **Variable Type:** Discrete Metric
* **Data Type:** Float
* **Units:** ratio
* **Column Name:** `pelvis_to_trunk_velocity_speedup`
* **Aggregation:** mean
* **Precision:** 2
* **Calculation:** Peak trunk velocity / Peak pelvis velocity
* **Optimal Range:** 1.25-1.75
* **Optimal Direction:** Higher is better

## Description

Pelvis to trunk speed up measures the multiplication factor of velocity increase from the pelvis to the trunk peak angular velocities.
This metric broadly indicates the efficiency of power transfer from the lower body to the core.

## Normative Ranges

Percentile distributions by competition level from the 2026 Q1 dataset; the optimal range spans the 75th–90th percentiles.

| Population         | Optimal Range (75th–90th) | 10th | 25th | 50th | 75th | 90th |
| ------------------ | ------------------------- | :--: | :--: | :--: | :--: | :--: |
| Youth              | 1.45 – 1.57               | 1.19 | 1.27 | 1.35 | 1.45 | 1.57 |
| High School        | 1.49 – 1.63               | 1.20 | 1.29 | 1.39 | 1.49 | 1.63 |
| College            | 1.36 – 1.50               | 1.14 | 1.19 | 1.29 | 1.36 | 1.50 |
| Professional       | 1.35 – 1.48               | 1.05 | 1.12 | 1.19 | 1.35 | 1.48 |
| Broad (All Levels) | 1.44 – 1.57               | 1.12 | 1.20 | 1.32 | 1.44 | 1.57 |

## Use Cases

* Power transfer analysis
* Kinetic chain efficiency