Force plate - what are the benefits of the most advanced force meter in the sports industry

Among the performance meters, an important role is played by the force plate, an instrument capable of detecting the force exerted on the ground by a person on the three axes of the plane and the resulting torques.
A force plate being tested
In sports, these platforms are used to analyse the thrusts given by an athlete during his walk, running or other physical exercises, such as jumping.  The force platform detects and measures accelerations, reaction times and possible thrust defects, meaning that it can be of excellent support during training for performance evaluations of competing and rehabilitating athletes.

What is a force plate?

From the outside, a force plate (or platform) looks like a simple rectangular pedestal, often joined to other platforms to form an entire floor. However, each force plate contains several sensors for detecting the moment of a force.

Therefore, in order to understand what a force plate is, it is first necessary to define what the moment of a force is. It consists of any cause capable of modifying the state of inertia or motion of a body, and manifests itself in the reciprocal interaction of two or more bodies.

graph depicting the progression of the force during a vertical jump
Three elements are needed to describe an applied force: 1) point of application; 2) intensity (or module or size); 3) direction. Two forces applied to the same point can be summarized in a single force, called the resultant force; it too falls under the spectrum of what a force platform can analyse, which detects it together with other parameters.

In summation, a force plate is an instrument that allows to detect and measure the forces that are produced during physical exercise, in order to optimize the athletic gesture and to "ground" all the power of an athlete, even in relation to a project of rehabilitation or recovery after injury.

Always look for your ankles!
More advanced types of force platforms also allow the recording of data relating to the pressure centre, which provide fundamental information for the detection of postural dysfunctions in an inertial state or in motion.

What a force plate can measure

Therefore, a force plate allows to evaluate the postural stability, the explosive force, the power, the reaction force from the ground. These data can later be used for the study of sports postures and movements, for diagnostics and rehabilitation.

The force plate measures direction, strength, reactive muscle activation time and other parameters and forces produced during specific movements of a sporting activity, like walking, running or jumping. In essence, it analyses motor patterns, applying kinematics to dynamics.

Together with other instruments, the strength platform is fundamental in the evaluation and improvement of the athletic gesture, correcting flaws resulting from an incorrect posture or wrong athletic technique.

Measurements of a force plate can be studied alone or combined with other data, such as limb kinematics, to determine the principles of locomotion. If an organism makes a standing jump from a force plate, the data from the force plate alone is sufficient to calculate acceleration, jump mechanics, power output, jump angle and jump distance using basic physics.
Lateral jump on a speed ladder
Simultaneous video measurements of the angles of the leg joints and the force plate output can allow the determination of torque, work and power in each limb, using a method called reverse dynamics.

How the force plate is used

The two main directions of use of the platform are those of prevention and performance. Postural stability, jumping and landing are the main areas of preventive investigation, in order to avoid injuries due to posture and the way in which certain movements are made.

As far as performance measurement is concerned, on the other hand, the exercises on the force plate involve various types of jumping and extension, to measure parameters such as power and height of the jump, or more basic locomotion movements, such as sprints, walks or agility drills.

Vertical jump on a plyobox
Especially in the area of jumping, force plates have proven to be a key element in the analysis of the athlete's performance. Jumping tests on force platforms are extremely repeatable, reliable and easy to conduct. The configuration time for each individual athlete is practically non-existent and large groups can be tested in rapid succession.

In addition, it is very difficult to cheat any kind of test on a force plate, either to mask an injury or pain or to appear stronger, faster, or more powerful than one really is, for the simple fact that you cannot cheat physics.

In which sports is the force plate useful?

In addition to athletics, the force plate has multiple uses in other sports. Skating, football, target shooting, but also volleyball, basketball and all sports in which there are stresses related to posture, jumping and levers.

Putting all the strength we have on the ground correctly is in fact fundamental both for the result and for the prevention of injuries, as already pointed out, but also for the correct delivery of physical effort.

Jumping a hurdle in the dark
In the field of injury and rehabilitation, one of the major applications of the strength plate is in gait analysis, in which the plate, if combined with other one so to form a linear path, can provide a series of accurate data on the of support and oscillation phases, the moments that constitute a complete step.

These data, generated by the pressure of the two feet on the force platform, the gait and the direction of the step in space, can provide a complete view of the distribution of the load on each foot and the symmetry of the body due to injuries or postural imperfections.

That said, force plates are still hard to use and expensive to manufacture, meaning that their application in the world of sports and rehabilitation is still limited to selected sport and medical facilities.

Nonetheless, the clear advantages brought by this evaluation tool are undeniable and can grant an ulterior edge to improve the athletic performance of the individual athlete, as well as a drastic reduction in the time to play for injured athletes. Furthermore, coaches can rely on additional data on their athletes, which they can then structure in chronological order to evaluate the individual growth of the athlete, or as a tool to compare the statistics of different athletes.

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