What are force plates?

A force plate (or force platform) is a device used to measure forces exerted onto the ground by a person as they perform a movement or exercise. 

Force plates use sensors to measure these forces, much like a set of bathroom scales, just with significantly higher strength, capacity and accuracy. 

The most common type of sensor used in this application are strain gauge load cells, which are used in ForceDecks.

The plates measure this force according to Newton’s third law of motion: " Every action produces an equal and opposite reaction"

In this context, this reaction is specifically referred to as ground reaction force (GRF). ForceDecks plates measure data in the vertical (v) axis and generate raw left and right limb (vGRF) output, which is summed to generate total vertical force upon which acceleration, velocity and derivatives are then calculated.

As force is applied to the plate, the sensors become distorted – not enough to be seen by eye, but enough to cause a voltage change in their specially-designed circuits.

These circuits are designed such that a change in voltage is relative to the amount of force applied, meaning that force data can be measured and collected accurately over time.

These outputs are transmitted to a computer as raw force-time data, which is then used to analyse the performance of the movement performance.

In ForceDecks’ case, algorithms are used to automatically analyse this raw data and determine key phases and performance metrics in commonly-used movements, such as the Countermovement Jump (CMJ), Drop Jump (DJ) and Isometric Mid-Thigh Pull (IMTP), among many others.

In turn, this data can be used by practitioners to monitor training and adaptation, potentially garnering more information from fewer tests in a shorter time.