> For the complete documentation index, see [llms.txt](https://valor-biomechanics.gitbook.io/api/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://valor-biomechanics.gitbook.io/api/terms-breakdown.md).

# Terms Breakdown

## What is a Valor "session"? 

A Valor session is a motion capture recording collected using the Valor mobile application and sensors. Each session can be categorized as either a **free session**, within an **assessment**, or as a standalone **exercise**. 

### <mark style="color:green;">Free Session</mark>

This is the Valor equivalent of a sandbox or free-to-move motion capture option and when recording one this becomes an individual Valor session. &#x20;

### <mark style="color:green;">Assessment</mark>

A Valor assessment is similar to a workout program or screening template which is essentially a container or group of multiple preset exercises. Each preset exercise in a Valor assessment is an individual Valor session.&#x20;

### <mark style="color:green;">Exercise</mark>

Valor also provides the ability to use our extensive 100+ list of exercises to choose from and record a standalone exercise if needed. This will also be captured as an individual Valor session.&#x20;

## Range of Motion

The Valor API returns primarily joint kinematics information, the most critical being range of motion for any movement or exercise recorded on the platform. In addition we provide velocity, acceleration, and deceleration statistics of a movement or exercise.&#x20;

The full maximum, average, and average maximum across multiple repetitions of a movement are provided for each joint's range of motion, velocity, acceleration, and deceleration. These values help determine the effective mobility of an athlete during joint rehabilitation to skill based movements.&#x20;

## Inverse Kinematics Metrics

The following are all the inverse kinematics metrics present on the Valor platform for each session that are determined by our custom biomechanics driven model. **Note:** The model from which these joints and their metrics are derived is always calibrated to a 0 degree offset for each joint excluding left & right shoulder abduction/adduction which is calibrated to a 5 degree offset.&#x20;

* <mark style="color:green;">**time**</mark>**&#x20;-** the time relative to the start of the session (sampled at 60 Hz)

### **Central Joints**

* <mark style="color:green;">**waist\_rotation**</mark> - the global rotation of the pelvis (as defined by a horizontal line between the hip joint centers). **Not** augmented by handedness therefore clocwise rotation of the pelvis (to the right from start of session) is positive and counterclockwise rotation of the pelvis (to the left from start of session) is negative&#x20;
* <mark style="color:green;">**waist\_extension**</mark> - the forward/anterior or backward/posterior tilt of the pelvis (as defined by the line between the hip joint centers). Anterior tilt is positive and posterior tilt is negative.&#x20;
* <mark style="color:green;">**waist\_bending**</mark>**&#x20;-** The side tilt of the pelvis (as defined by the line between the hip joint centers). Right tilt is positive and left tilt is negative.&#x20;
* <mark style="color:green;">**lumbar\_rotation**</mark>**&#x20;-** torso rotation around the spine relative to the pelvis. Rotating right is positive and rotating left is negative.&#x20;
* <mark style="color:green;">**lumbar\_extension**</mark>**&#x20;-** torso extension at the lower back relative to the pelvis, such that a positive extension is towards the player’s anterior/front
* <mark style="color:green;">**lumbar\_bending**</mark>**&#x20;-** torso lateral bending relative to the pelvis such that bending towards the right is positive and towards the left is negative
* <mark style="color:green;">**trunk\_extension**</mark>**&#x20;-** torso extension relative to the ground, such that a positive extension is towards the player’s anterior/front

### **Lower Body Joints**&#x20;

* <mark style="color:green;">**hip\_flexion\_l/\_r**</mark>**&#x20;-** hip flexion (positive) and extension (negative)&#x20;
* <mark style="color:green;">**hip\_rotation\_l/\_r**</mark>**&#x20;-** hip external (positive) rotation and internal (negative) rotation. Best captured when performing range of motion specific testing for this angle&#x20;
* <mark style="color:green;">**hip\_adduction\_l/\_r**</mark>**&#x20;-** hip abduction (positive) and adduction (negative)
* <mark style="color:green;">**knee\_angle\_l/\_r**</mark>**&#x20;-** knee flexion (positive) and extension (negative)
* <mark style="color:green;">**knee\_valgus\_l/\_r**</mark>**&#x20;-** knee valgus (positive) and varus (negative). Analogous to knee abduction (positive) and adduction (negative)
* <mark style="color:green;">**ankle\_angle\_l/\_r**</mark>**&#x20;-** ankle dorsiflexion (positive) and plantar-flexion (negative)
* <mark style="color:green;">**ankle\_inversion\_l/\_r**</mark>**&#x20;-** ankle eversion (positive) and inversion (negative)
* <mark style="color:green;">**ankle\_add\_l/\_r**</mark>**&#x20;-** ankle abduction (positive) and adduction (negative)
* <mark style="color:green;">**shin\_angle\_l/\_r**</mark>**&#x20;-** shin angle relative to ground and an analog to ankle dorsiflexion/plantar-flexion. Bending shin forward is positive (ankle dorsiflexion) and bending shin backwards is negative (ankle plantar-flexion)&#x20;

### **Upper Body Joints**&#x20;

* <mark style="color:green;">**arm\_flex\_l/\_r**</mark>**&#x20;-** shoulder flexion (positive) towards to the front of the body and extension (negative) towards to the back of the body in the sagittal median plane&#x20;
* <mark style="color:green;">**arm\_rot\_l/\_r**</mark>**&#x20;-** shoulder external (positive) rotation and internal (negative) rotation. Best captured when performing range of motion specific testing for this angle (e.g. 90-90 shoulder rotation test)
* <mark style="color:green;">**arm\_add\_l/\_r**</mark>**&#x20;-** shoulder abduction (positive) away from body's center and adduction (negative) towards body's center in the coronal/frontal plane&#x20;
* <mark style="color:green;">**arm\_horz\_flex\_l/\_r**</mark>**&#x20;-** shoulder flexion (positive) and extension (negative) in the horizontal or transverse plane
* <mark style="color:green;">**elbow\_flex\_l/\_r**</mark>**&#x20;-** elbow flexion (positive) and extension (negative)

{% hint style="info" %}
**Note:** See images below for breakdown of shoulder movements and the conventional planes used to calculate the shoulder joint angles.
{% endhint %}

{% tabs %}
{% tab title="Plane Breakdown" %}

<div data-full-width="false"><figure><img src="https://2765674571-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FBvMDLkjtk6TG9ow3Oovj%2Fuploads%2FufvN1qb3BC3HqkD12NUf%2FHuman_anatomy_planes%2C_labeled.svg.png?alt=media&amp;token=6a4d035c-d623-44e4-adac-be07a6fa1525" alt="" width="563"><figcaption></figcaption></figure></div>
{% endtab %}

{% tab title="Shoulder Definitions" %}

<div data-full-width="false"><figure><img src="https://2765674571-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FBvMDLkjtk6TG9ow3Oovj%2Fuploads%2FljirjxweJh6Snj06ZhRT%2Fresource-center-shoulder-action.webp?alt=media&amp;token=456c8a9e-21fe-4c42-8395-307aa8d62225" alt=""><figcaption></figcaption></figure></div>
{% endtab %}
{% endtabs %}

### Misc.

* <mark style="color:green;">**\<joint angle>\_vel**</mark>**&#x20;-** the derivative vs time of the joint angle in units of degrees / s
* <mark style="color:green;">**\<joint angle>\_acc**</mark>**&#x20;-** the second derivative vs time of the joint angle in units of degrees / s^2