Kistler introduces portable digital 3D force plate for biomechanical measurements

Piezoelectric force plates provide athletes with valuable insights to improve their performance and support physiotherapists in treating injuries of the lower extremities. Among other things, the generated data can be used to identify uneven weight distributions after injuries or suboptimal movements. Flexible and easy handling of the measurement hardware is important to most users in everyday practice. Kistler therefore made sure to simplify the measuring chain during development so that the force plate can be used for various measuring scenarios.

The new 3D force plate with integrated charge amplifier delivers the measurement results via an Ethernet interface in a digital format. An external data acquisition system is no longer necessary. A specifically shielded hybrid cable handles both data transfer and power supply without affecting the quality of the measurement results. The digital technology also allows several force plates to be connected directly in series – a significant simplification compared to the analog version. Here, each plate had to be connected individually to an external data acquisition system. 

Up to 16 force plates – twice as many as with the analog predecessor – can now be connected in a single measurement chain, for example to form a gait analysis walkway. Integrated PTP (Precision Time Protocol) synchronizes any number of force plates in the network. In addition, Kistler's DataServer interface enables users to integrate motion tracking systems and other third-party measurement systems. The force plate can be installed on a mounting frame or walkway and has flexible feet that can be fixed in the required position. It is available in two sizes (600x500 or 300x500 millimeters).

Precise measurement thanks to piezoelectric sensors

The piezoelectric measuring principle leads to precise results in a broad measurement range (0 to 10 kN). Four sensors, each in one corner of the force plate, measure the force with which the test subject pushes against the ground (ground reaction force, GRF) during movement. The quartz in the sensors emits small electrical charges that are proportional to the applied force while a charge amplifier integrated into the force plate makes this effect usable for data collection. The 3D force plate measures forces in all three spatial axes and reliably determines the exact center of pressure (COP). Setting up the force plate is remarkably easy as the sensitivities of the sensors are stored on the force plate and no longer have to be entered manually during recalibration.

Despite all innovations, Kistler has not forgotten about longtime users. For those who work with older models but want to benefit from the advantages of digital technology in the future, Kistler offers a retrofitting service. Users can send in their analog force plates to be upgraded with digital electronics and brought up to date.