Torso Rock

Summary

Torso Rock measures the average angular rotational range of the chest to the left and right.

Details

In more detail, Torso Rock represents the average angular rotational range of the torso, measured at the sternum once per second along the local sagittal axis (the sagittal axis intersects the lower back and the abdomen area above the pelvis).

A larger Torso Rock value indicates higher average torso rotation and a lower value indicates more limited rotation. Although torso movement from side to side can generally be called “rocking,” it is important to note that the amount of rocking observed is dependent on both torso rock and pelvic rock.

Score

Each clockwise and counterclockwise rotation occurring within a second is recorded and averaged, resulting in an angular score.

Value Range	Level	Visual Reference
12°+	Bad	Upper body is tilted wide to the left and right
8 - 12°	Low	Upper body is tilted to the left and right
4 - 8°	Moderate	Normal movement
0 - 4°	Good	Steady upper body