Load
Radians
Per Second.
A unit that measures rotational acceleration — how quickly the head is spinning or twisting during an impact. Where G-Force measures straight-line force, Rad/s captures the rotational component that is widely considered the primary driver of concussion and diffuse brain injury.
Rotational Force
How the head
twists on impact.
Rad/s measures twisting forces when the head spins or whips on impact — and it's one of the most significant factors in determining brain injury severity. Even impacts that feel minor can carry serious rotational force.
The Unit Explained
What exactly
is Rad/s?
Rad/s stands for radians per second — a unit of angular acceleration that measures how quickly something is spinning faster or slower over time.
Why It Matters
The most damaging force
you can't see.
The brain is a soft tissue suspended in fluid. When the head rotates rapidly, different regions of the brain move at varying speeds — creating shear stresses between layers of brain tissue. This rotational force is strongly associated with concussion, diffuse axonal injury (DAI), and long-term degenerative diseases like Chronic Traumatic Encephalopathy (CTE).
While a single high linear impact can be dangerous, it is often the rotational component that leads to the most severe neurological disruption. For HIT users, tracking rad/s provides critical insight into invisible but damaging forces — particularly in sports with frequent or unexpected collisions such as rugby, diving, and hockey.
Impact Classification
Three levels.
Clear thresholds.
Every rotational impact recorded by HIT is classified into one of three levels — giving instant, colour-coded clarity on severity.
