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You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to sports facilities.  
         [0003]     2. Description of the Related Art  
         [0004]     Sports facilities having synthetic surfaces such as artificial turf can better withstand wear and tear than natural grass. The synthetic surfaces currently in use, however, are not particularly suited for different sports nor are they easily configurable for multiple purposes.  
       BRIEF SUMMARY OF THE INVENTION  
       [0005]     In one embodiment, the invention enables people to learn and practise sport, choosing from amongst the most widely practised activities the one that they prefer and is most suitable for their own physical and mental aptitudes.  
         [0006]     According to the present invention, tone embodiment provides a multi-purpose sports facility  
         [0007]     In the currently preferred embodiment, the multi-purpose facility according to the invention makes it possible to start from the basic sport of running and evaluate the physical resources, aptitude, and resistance manifested by the individual person (with particular attention paid to young people aged between six and eighteen) to enable him or her to choose the most suitable sports activity from a set of activities comprising, for example, athletics, soccer, volleyball, tennis, basketball, and handball.  
         [0008]     A youngster who starts by taking up running is then able to train by practising all the activities on a single multi-purpose facility with learning functions. Subsequently, he is able to specialize in one or more sports activities so as to be able to develop gradually his own capabilities and achieve increasingly satisfactory results.  
         [0009]     The multi-purpose facility according to the invention enables the drawing-up of training programmes for the various sports, with the added possibility of it being set out according to different schemes (in particular as regards the choice of the sports), as dictated by the preferences, and the local customs and cultures of different geographical areas. The multi-purpose facility in question can be set up at a low cost so as to make it available (for example, by renting) at contained costs and for the benefit of entities such as schools, local authorities, and sports clubs.  
         [0010]     In the configuration according to a preferred embodiment, the sports facility comprises in any case, peripherally, a running track, for example of a fairly short length (typically 200 meters) and/or with a number of lanes, which encloses inside it one or more pitches or courts for practising different sports activities.  
         [0011]     In a particularly preferred way, the sports facility in question is obtained using as base structure a synthetic-grass covering comprising a sheet substrate with a plurality of filiform formations extending from the substrate for simulating the grass blade of natural turf, as well as a particulate filling material, or infill, dispersed between the filiform formations so as to keep the filiform formations themselves in a substantially upright condition.  
         [0012]     Preserving the same basic structure and modifying parameters such as, for example, the extension of the filiform formations and the nature, density, as well as the thickness of the particulate infill, it is possible to bestow on different areas of the multi-purpose sports facility characteristics that are different according specifically to the various sports activities which are to be carried out thereon, possibly in accordance with the respective national and international sports federations.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)  
       [0013]     The invention will now be described, purely by way of non-limiting example, with reference to the annexed plate of drawings, in which:  
         [0014]      FIG. 1  is a general plan view of a multi-purpose sports facility according to the invention; and  
         [0015]      FIG. 2  is a schematic reproduction, in an ideal vertical cross section, of a portion of the base surface of the sports facility of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     In the attached plate of drawings, the reference number  10  designates as a whole a multi-purpose sports facility comprising, in the example of embodiment illustrated herein:  
         [0017]     an athletics track  12  constituted by an annular running track, for example of a fairly short length (typically 200 meters) and/or with a number of lanes (from two, to six, to eight), which is circumscribed by a boundary  14 , here having a generally rectangular shape, which encloses an internal space  16 ; and  
         [0018]     one or more fields, pitches or courts  18 ,  20 ,  22  for practising different sports activities made in the space  10  delimited by the running track  12 .  
         [0019]     For purpose of illustration, without in any way limiting the scope of the invention, the dimensions of the rectangular boundary  14  may typically be in the region of 100-110 meters in length by 40-50 meters in width, which corresponds to a total surface of approximately 5000 m 2 .  
         [0020]     Advantageously, the running track  12  has, along its major sides, one or more rectilinear stretches  120 ,  140 , which extend practically throughout the length of the boundary  14  and can be used, for example, for short-distance running (for example 100 m) or else for jumping activities (long jumping, pole vaulting, hop-step-and-jump, etc.).  
         [0021]     As regards the areas  18 ,  20 ,  22 , the example of embodiment to which  FIG. 1  refers envisages that the area  18  is a football pitch (five-a-side football), having for example dimensions of 40×20 m. The area  20  may be instead a basketball court with typical dimensions in the region of 28×1 5 m. The area  22  is a volleyball court with typical dimensions in the region of 9×1 8 m.  
         [0022]     Of course, both the number of pitches and courts  18 ,  20 ,  22  and their arrangement, the dimensions indicated, as well as the nature of the areas in question are intended purely to provide an example and hence in no way limit the sphere of protection of the invention.  
         [0023]     In a particularly preferred way, all the various pitches, tracks, etc.  12 ,  18 ,  20 ,  22  illustrated herein (or at least one subset thereof) are obtained using, as base structure, a structure of synthetic-grass covering of the type illustrated in  FIG. 2 .  
         [0024]     This is a structure comprising a sheet substrate  1  with a plurality of filiform formations  2  extending from the substrate  1  so as to simulate the grass blade of natural turf, and a particulate filling material, or infill,  3  dispersed between the filiform formations  2  so as to keep the filiform formations  2  themselves in a substantially upright condition.  
         [0025]     In a particularly preferred way, the particulate infill  3  consists of a substantially homogeneous mass of a granular material chosen in the group consisting of polyolefin-based materials and vinyl polymer-based materials, for example of the type described in EP-A-1 158 099, in the name of Mondo S.p.A., the assignee of the instant application.  
         [0026]     Recourse to this structure makes it possible to bestow on the various surfaces  12 ,  18 ,  20 ,  22  biomechanical characteristics differentiated according to the particular specialities that are to be practised on a given pitch or track. This is obtained by modifying the characteristic parameters of the constituent elements of the structure (for example, the filiform formations  2  and the infill  3 ).  
         [0027]     For example, a first parameter is the grain size of the infill  3 . It is therefore possible, for example, to reserve smaller values of grain size to pitches or tracks for which a higher compactness (i.e., a greater “hardness”) is desired, as in the case of the basketball court, such as the pitch  20 , whilst greater values of grain size are usually reserved to pitches for which characteristics of greater softness or pliancy are desired.  
         [0028]     Substantially similar considerations apply as regards the density of the infill. The same considerations are valid as regards the apparent density of the infill and as regards its grain size, as well as the amount of dispersed material.  
         [0029]     In another embodiment, the infill may consist simply of sand, or of a filling with high hardness, or else, in a particularly preferred way, of a polyolefin-based material or a vinyl polymer-based material. Particularly preferred choices for said material are polyethylene, recycled polyolefin material or else a recycled vinyl polymer.  
         [0030]     It will be appreciated that the filling materials can be the same as one another or else different for the various playing surfaces  12 ,  18 ,  20 ,  22 .  
         [0031]     Other parameters on which it is possible to adjust in order to modify selectively the biomechanical characteristics of the various tracks, pitches or courts  12 ,  18 ,  20 ,  22  are, for example, the density (points/m 2 ) and/or the length of the filiform formations  2 , understood as the distance between their proximal ends (designated by  2   a ), which are anchored to the substrate  1 , and their distal ends, which extend upwards.  
         [0032]     In a particularly advantageous embodiment of the multi-purpose sports facility, it is envisaged to use, for two or more of the tracks or pitches  12 ,  18 ,  20  and  22 , a sheet substrate  1  with a plurality of filiform formations  2  extending from the substrate  1  with uniform characteristics. In this case, differentiation of the biomechanical characteristics of the various areas  12 ,  18 ,  20 ,  22  is obtained by primarily adjusting the characteristics of the infill  3  and/or the characteristics of distribution of the material itself on the substrate.  
         [0033]     The multi-purpose sports facility described herein presents the further advantage of being suited both as regards convenience of laying, and as regards a possible convenient reconfiguration of the various tracks, pitches or courts (variation in number, position, orientation, and characteristics thereof, also according to requirements of use that can vary in time), as well as regarding a convenient operation of dismantling, with practically complete recycling of the component materials, according to the modalities described, for example, in EP-A-1 319 753.  
         [0034]     Advantageous variant embodiments of the structure of covering which can be used for the multi-purpose sports facility according to the invention are described in EP-A-1 375 750, EP-A-1 371 779 and in the European patent application filed under No. 03425369 or else in EP-A-0 874 105 and EP-A-0 913 524.  
         [0035]     All of the above U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, are incorporated herein by reference, in their entirety.  
         [0036]     Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary widely with respect to what is described and illustrated herein, without thereby departing from the scope of the present invention.

Summary:
A multi-purpose sports facility is provided with a common base structure comprising a plurality of areas, each of which constitutes a track, pitch or court for practising a respective sports activity. The invention enables people to learn and practise sport, choosing from the activities most widely practised the one that they prefer and is tracks, pitches or courts most suitable for their own physical and mental aptitudes.