It is now frequent to see sportsmen such as players wear mini-twist in contact with the skin, during games and especially in workouts. These clothing aim to contain devices – i Wearable – Like GPS sensors, capable of carrying out measurements of specific parameters such as each meter path, any cardiac variation and any acceleration or deceleration. Used in a multitude SI sports including football, tennis and cycling, for example allow to modulate loads and training strategies, improve the performance of athletes and prevent the onset of accidents or favor their recovery. How do they work and what do these devices specific?
How GPS work
The technology behind the operation of these systems is, in fact, the GPS acronym for Global Positioning System. Thanks to the GNSS (Global Navigation Satellite System) the distance between the device and the satellites in orbit is calculated and its exact location is triangled. Often these devices also include other sensors as well as GPS ones, such as accelerometers (responsible for tracking movements), gyroscopes and heart rate monitor.
What GPS is for football and what they measure
Thanks to the ease of use, the reporting efficiency of the results, the remote usability and to the innovation in strong growth, the GPS are increasingly used in football clubs, not only of a high level. They are inserted in the aforementioned breastfish and positioned in the center of the back, between the shoulder blades, so as not to disturb the movement and avoid risky impacts. Various versions are available on the market that differ in price, measures and other characteristics. Among these, one of the most important is the sampling frequency (measured in Hz) which indicates the number of times to the second in which an analog signal is measured and converted into digital data. In general, among the most significant quantities that these systems aim to record, we find:
- Distance traveled
- Average speed, maximum speed and speed of specific traits
- Accelerations and decelerations
- Changes of direction
- Running methods
- Physiological data (such as heart rate intervals)
- Heatmap and positioning in the field
All quantified parameters are then transmitted to specific software capable of schematizing the results (for example for athlete or role) and, depending on the model, allow various comparison, analysis and reporting actions.
Because they are used
The methodology of training, especially for competitive purposes, rests on an apparently simple assumption and on which many experts agree: structure the training based on the peculiarities of the race and the technical gesture. Starting from this assumption, it is essential to analyze, from an increasingly accurate point of view, the intrinsic variables of a sport to achieve better results in terms of performance. This is the first reason why GPS sensors are used.
These systems make it possible, in more specific terms, the measurement of the player’s workload during training and matches and the subsequent analysis of the registered parameters allows to understand the answers from the athletes and to change their training on the basis of what emerged. The workload is divided into internal and external load. The first is the result of the physiological and psychological responses given by the player to external stimuli (heart rate, concentration of lactic acid etc.), the second, however, is defined as the set of external stimuli to which a footballer is exposed during the activity (distance traveled, number of sprints etc.). This is why, as we have seen previously, data relating to variables are gathered so different from each other.
Just in relation to the training load, recent research have shown that its sudden changes are directly connected to an increase in the risk of accidents. The conscious use of the GPS sensors, therefore, not only can maximize the efficiency of the training, but can also help prevent the onset of accidents and, subsequently, facilitate their recovery trying to equal, or almost, the pre-injury parameters.
Obviously, the data collected by the GPS are not able to provide a complete and definitive picture on the physical, psychic and medical situation of the player. For this reason, it is essential to adopt a multidisciplinary approach and encourage the continuous cooperation of the staff (doctors, coach, athletic trainers and therapists) to be able to better examine the results obtained and define a correct action plan.
