How Are Force Plates Used?

Ground Reaction Force

• Force plates are instruments that measure ground reaction force -- the force the ground exerts on a body that is in contact with it. A person stands or walks on the force plate, and the plate measures balance, gait and force. Sports and medicine research centers use force plates for training and rehabilitative purposes.

Center of Pressure

• A force plate gathers all the forces that act between the foot and the ground to create a single ground reaction force vector. The point on the plate where the ground reaction force is applied is called the center of pressure (CP). All of the small reaction forces from the foot collectively exert pressure near the CP. The CP can change if a pad is added on top of the surface of the force plate.

Simple and Complex Plates

• Simple force plates feature a single pedestal which acts as the load cell. These plates measure the vertical force applied at the CP. More complex force plates have more than one pedestal to measure a person's load. Some are capable of measuring the CP and the vertical force at the same time.

Real Life Application

• Strength and conditioning coaches and physical therapists often use the data accumulated from force plates to determine appropriate workout programs. The specialists are able to see the muscle activation and movement patterns of their subjects, and provide useful exercises to improve their physical condition. With the information, specialists can track progress in workout programs and adjust the prescribed exercises accordingly.