What is a force plate?
A force plate is a measuring platform with a piezoelectric force sensor in every corner. Force plates can be used to characterise biomechanical processes such as walking, running or jumping, for example, for performance diagnostics in sport, for clinical analyses or in research.
A three-component force plate contains piezoelectric sensors that measure the forces in the three main axes: the vertical, the horizontal and the transverse direction. This information can be used, for example, to answer specific questions in research or to analyse the movement of the centre of mass.
What does a force plate measure?
Force plates measure the so-called ground reaction force. According to Newton’s third law, this is the force that acts on a human body during a movement. At rest, the ground reaction force corresponds to the weight of the body; during movements, this force changes due to acceleration effects. Ground reaction forces are among the most commonly measured biomechanical parameters and help to characterise the movement patterns of a person.
What needs to be taken into account when using force plates?
There are mobile and permanently installed force plates. Ideally, the force plate is installed flush with the underlying ground so as to facilitate natural movements. Otherwise, the selection should be based on the application purpose:
- For simple analyses, e.g. for vertical jumps, a portable 1D-force plate is sufficient
- Trainers and coaches usually work with a portable three-component force plate for recording the balance and stability of their athletes
In research, permanently installed 3D-systems are normally used. To record complex movement patterns, force plates are used in combination with video cameras or motion-capture systems.
What is a 3D force plate?
A 3D force plate is a measuring platform that is used in rehabilitation, for example, for gait and balance analysis or in sport for measuring highly dynamic movement sequences. The force to be measured is applied via a cover plate to four 3-component force sensors, which are installed under high pretension between a mounting foot and the cover plate.
Each of the sensors is equipped with three quartz plate pairs, of which one responds to pressure in the z-direction and the two others shear in the x and y directions. Measurement takes place practically displacement free.
What are 3D force plates used for?
3D force plates are used in biomechanical basic research and in sports for the measurement of ground reaction forces, torques and centre of pressure (COP) that occur when a person stands, steps or jumps on the force plate. The data measured along the vertical and horizontal force axes help to characterise highly complex movements.
3D plates can also be used to measure and analyse lateral jumps. Movement analyses in sports help to improve the performance of athletes and to avoid injuries. Trainers and coaches usually work with a portable three-component force plate for recording the balance and stability of their athletes.
In research, permanently installed 3D systems are typically used. To record complex movement patterns, force plates are used in combination with video cameras or motion-capture systems.
What is the difference between a 1D force plate and a 3D force plate?
Because the measuring elements of a 1D force plate are 1-component sensors, they can only be used to measure the vertical forces that occur during walking or jumping. This is where the difference between a 3D force plate based on 3-component sensors lies.
The 1D force plate is used to measure the vertical forces exerted during jumps, such as:
- Counter movement jumps
- Squat jumps
- Drop jumps
Advantages of Kistler Force Plates
Kistler force plates deliver precise, reliable data in research, clinical gait analysis and rehabilitation – for applications ranging from prosthetic adaptations to gait analysis with animals.
Integrated piezoelectric measurement technology captures forces and moments with utmost precision: even the smallest changes in the gait pattern or shifts in the centre of gravity are detected. And thanks to accurate force measurements, the centre of pressure can be calculated exactly for precise inverse dynamics. The main advantages of Kistler piezoelectric force plates for gait analysis are:
- High resolution and reliability
- Long-term stability across an extremely wide measuring range
- Recording of very small forces (e.g. in children)
- Specific applications for humans and animals
To find out more about Kistler force plates, visit our page now: bmec.asia/kistler
More Information
Kistler Group | https://www.kistler.com/GB/en/force-plate/C00000113 ; https://www.kistler.com/GB/en/3d-force-plate/C00000090 ; https://www.kistler.com/GB/en/gait-analysis/C00000024
Kistler Group
