The players' point of view
Although synthetic grass pitches have made notable progress in terms of quality, they do not seem to convince professional players, but the problem of natural pitches becomes even more complex because there are no reference standards. In fact, very often, the complaints of a visiting team have no weight and, in the host club's attempt to justify itself, the problem is attributed to gratuitous controversy, possibly due to the poor performance of the opposing team.
On a natural/synthetic/hybrid grass pitch, the softness, stability, bounce and rolling of the ball can be easily measured but the traction of the surface seems to be the most important aspect because during the match the player accelerates, decelerates and changes direction continuously so the interaction of the player's shoes with the sports surface is essential to support his weight and avoid slips and falls due to the playing surface. On the one hand, players very often complain about the conditions of the playing field but, on the other hand, it is difficult to measure object parameters.
Reviewing player complaints
In our work, we are always in contact with managers who have been players and these complaints are the main topic when we discuss the conditions of the field, in particular the type of sports surface to be created, also based on the experiences they have had in the various fields on which they played.
Curious as always, we tried to delve deeper into and analyze these complaints in relation to the technical characteristics of the pitch and its maintenance and we were able to note some essential aspects.
When the pitch is hard players experience back pain. Various studies have been conducted and the industry has developed testing techniques such as Clegg's hammer, which offers the possibility of measuring the hardness of the sports surface with extreme ease. However, it is believed that on synthetic turf pitches with rubber infill "the elastic return that acts like a grinding wheel on the player's back" deserves greater investigation.
On the interaction of the player's shoes with the sports surface, once again, tests are only carried out on synthetic grass. One test concerns the slipperiness of the surface using an instrument that simulates the player's foot with a shoe which, by kicking on the synthetic turf up to the stopping point, provides measurements, while on the tensile resistance a round plate with studs similar to those of the shoes is used; by progressively rotating the plate, the maximum force exerted to rotate 45° is measured.
According to some studies, during the player's rotational action, ankle and knee sprains are more frequent on synthetic grass fields because it seems to cause excessive grip on the player's shoe, while natural grass tends to yield to the player's rotational force, just like the safety pin of an engine shaft. Some attribute this "greater grip" to the fact that synthetic grass is made with less resilient fibres, after 2-3 seasons, they tend to remain "lying" on the surface and therefore significantly increase friction and resistance to rotation, in particular with the increase in temperature which seems like a sensible explanation. They argue that this risk can be reduced if the synthetic pitch is properly packed and brushed frequently, lifting the artificial fibres. On the other hand, the alternative of a natural grass field which fills with holes after a few hours of play requires expensive maintenance interventions to restore them because the irregularity of the surface constitutes a greater danger which causes distortions.
Notwithstanding that an irregular natural grass surface is more dangerous than a synthetic pitch, the biggest problem on synthetic grass is not the excessive "cleat grip" on the synthetic fibres, also because the player does not perform rotational actions on himself like a dancer. On the contrary, the biggest problem seems to be the slipperiness of the surface due to poor grip of the cleat because a) the infill material has no consistency precisely because the infill is loose granular material and b) when the fibers are "lying" on the surface the cleat does not penetrate sufficiently so it slips more especially when the surface is wet.
The testimonies of some young players made us reflect because, during training, we recorded a) greater speed during running, and b) less slipperiness during acceleration, deceleration and changes of direction. Other adult players complain that when they play on artificial turf,their ligaments burn. These recurring testimonies led us to reflect on the possible causes; the only plausible explanation is the grip of the studs on the sports surface. His stability with every game action depends on the player's grip on the surface.
The real problem is slipperiness due to the lack of cohesion of the surface
A synthetic grass pitch, despite being in excellent condition, does not have enough grip because, even if it were to sink completely, the infill granules are dissolved between the fibres, so the playing surface has no cohesion. The player feels this instability and when he runs the ligaments are stressed more to support his balance. Professional players are the first to notice this difference and often categorically refuse to play on a synthetic grass pitch.
