The Force Plate, like any sensor, has a limit to how quickly it can respond to a change. If a very short impulse is applied to the force plate, it will vibrate, or ring, for a short while. That ringing can interfere with your measurement.

Revised (FP-BTA) and Go Direct Force Plate

The current version of the Force Plate (FP-BTA) and the Go Direct® Force Plate (GDX-FP) have load cells ring frequency of approximately 50 Hz (or a period of approximately 20 ms). This means that this is the shortest impulse you can effectively measure. In order to capture an impulse of this shortest period we recommend sampling at 500 Hz (GDX-FP) or 1000 Hz (FP-BTA) in order to capture sufficient data to characterize the impulse.

If the actual impulse period is shorter than 20 ms, the data will not reflect that due to the ring frequency. Sampling faster will not provide additional resolution.

Original (FP-BTA) Force Plate

The original version of the Force Plate (those shipped before November 10, 2023) uses different load cells that have a ringing frequency of ~250 Hz, with a ~4 ms period. Even a 10 or 20 ms impulse will be distorted by the finite response time of the force place. In order to really see the structure of an impulse, the impulse should be ~200 ms or longer.

This means that you can bounce a soft, squishy balls off of the force plates and see the details of the impulse. If, however, you attempt to measure the impulse of a hard ball bounce, such as baseball or a golf ball, your data will be adversely affected by the ring frequency.

Additional Information

Published: January 10, 2017. Updated: May 1, 2025.