Equipment for outdoor fitness and related kit Description Technical Field The invention relates to the field of urban equipment for outdoor fitness. More particularly the present invention aims at providing an equipment, which is mainly intended for open air physical exercise of elderly people or of those undergoing motor rehabilitation, and a relative kit with a complete set of computerized devices to provide an improved accessibility to the service. Background Art In the last few years, the practice of outdoor fitness in specially equipped areas has gained momentum in Italy and in numerous other countries in the world. Actually, fresh air has proved to be a decisive parameter for a better physical performance during the exercise and for improving the individual wellness. Therefore, various areas have been dedicated to these activities in various parks and in other strategic places of city life (viewpoints, seafront, squares etc.) by providing various kinds of equipment in order to include a user segment as wide as possible of the population. An example is given by the patent application US20080081741 A1 of J.P. SARGEN and A.K. HONGO. This invention relates to a multi-person elliptical trainer suited to improve one’s practice in aerobic exercises and generally one’s fitness. This equipment includes one or more training stations mounted on a support frame. Each training station includes a pair of parallel tracks which are roughly parallel, each track being pivotally attached to a swing arm with pedal. A user can place a foot on each of the foot pedals, grasp the swing arm handles and rotate the pedals by rhythmically pushing and pulling the swing arm handles, while using the pedals to simulate a more or less fast pace. A further example is the object of patent application DE102013111535A1 (K. KAISER). This invention concerns an equipment of outdoor fitness comprising a lever mounted in a movable way on a stationary part of the equipment, so that the forces acting on the lever will flow by means of a spring to the stationary part. Moreover, this invention concerns a prefabricated spring made of an elastomeric material to be used on this equipment. Another example is disclosed in patent application GB2483161A (M. MILLER, S. BEER). This invention relates to a center for outdoor fitness including a fitness center capable of generating electric energy and of allowing this energy to be consumed in an external place or be transmitted to the network and a monitor for measuring a parameter related to the generated electric energy. A set of devices used for the exercises can supply a single energy collection module. A condenser or a battery regulated by a valve can be employed to accumulated/store the energy. An energy storage module is also described in detail and this module can also be equipped with a monitoring means of various kinds. It should be clear that none of the inventions described so far is directed to specific target users; actually, the elderly cannot use these devices. Physical exercise done by persons of reduced mobility obviously requires a specific study and accurate instructions on how to use the available devices. To date, these cautions are substantially disregarded by the market. An object of the present invention consists in indicating/suggesting an innovative equipment for outdoor fitness together with a computerized kit, suited to provide clear explanatory information through a display and through voice instructions. This equipment and kit are specifically conceived for an elderly user, who is inactive or has reduced mobility, in order to stimulate low impact movements for increasing the spine and pelvis flexibility, and to reinforce the leg musculature. This equipment has firm/solid and stationary components, in such a way to avoid sudden joint/muscle movements capable of causing (even serious) damage to elderly users. Even more advantageously, the kit comprises simple controls, which are clearly visible to everyone and are all connected to a speaker such as to engage in the best possible way also users with a reduced vision. Description of Invention According to the present invention an equipment for outdoor fitness is realized, together with a related kit, suited to combine the positive aspects of a design specifically studied by experts in the field of physiotherapy and osteopathy, with those of mechanics and information technology, so as to provide a result which is both economical and safe. This equipment for outdoor fitness for people with reduced mobility results in many advantages for the users, like a reduced risk of developing chronic diseases, of making sudden movements, or of falling during the training, thereby reducing strain in the knees, the risk of low back pain, and improving the circulation in the lower limbs, so as to facilitate digestive processes and generally promote an adequate exercise with the aim of ensuring better psychophysical conditions. The present equipment may be installed advantageously in parks and other crucial places of city life (viewpoints, seafront, squares, etc.), thereby allowing its use to a large segment of the population. The strong points of this equipment are inherent in its unique and up-to-date design, its planning done with the scientific support of field specialists, its great safety of use, and its facilitated accessibility due to the presence of said kit for said equipment. In one of its preferred embodiments the equipment includes a bush-hammered base having a weight that suffices to counter-balance the loads and prevent the overturning of the equipment. The anti-slip bush-hammering is directly realized on a concrete filling or on a different filling material which is specially designed to this purpose. The base is prolonged forming a shaped frame of variable form, depending on the use required from said equipment. Said shaped frame then extends up to a seat within which an electrical coil may be present to allow heating of the seat. Said frame may advantageously be provided in various colors in order to better fit to the context/environment where the equipment is installed and in order to present a nice design appearance. Possibly and advantageously an infographic is applied on the frame for illustrating the correct modality of execution of the exercises associated with the equipment, while a scannable QR code is also applied on the frame to provide additional information. This infographic may also give information associated with the caloric/energy expenditure due to the use of the equipment, the expected heart rate increase, and the involved muscle groups. In another preferred embodiment, said shaped frame extends forming two armrests on each of which a handlebar is located. Said handlebar is integrally connected to the shaped frame and provides a safe hand grip for doing physical exercise. In another preferred embodiment said seat has a recess in which a rotary seat is installed; said rotary seat allows movement of the hips and pelvis; said shaped frame extends to form a back on which extrusions for self-massage are installed; said extrusions for self-massage arranged to correspond to the lumbar zone are ideal for alleviating pain caused by spine/back problems originating in an incorrect posture. In another of the preferred embodiments said shaped frame forms a closed pyramidal shape at whose ends are installed said handlebars; this realization allows muscle stretching, a tension reduction in the lower limbs, and promotes improved circulation. The kit associated with said equipment for outdoor fitness comprises at least a totem and at least an equipment piece. In its preferred embodiment said totem includes: a projecting roof having the function of protecting from bad weather the more sensitive, technological part; a display equipped with anti-vandal buttons with braille, a loudspeaker and a current outlet for recharging mobile devices. Said totem may be connected with a solar panel and the mains to provide the equipment with electricity, possibly in order to turn on (that is, to activate) the heating coil of the heatable seat. All sensitive parts of said totem are waterproof, solid and vandal-proof. The advantages offered by the present invention are obvious in the light of the description put forward so far and they will be even more clear thanks to the annexed drawings and their detailed description. Description of Figures The invention will be described in the following in at least one of its preferred embodiments for illustrative and non-limitative purposes and with reference to the annexed drawings, in which: -FIGURE 1 shows a tridimensional view of some preferred embodiments of the equipment for outdoor fitness 100; -FIGURE 2 shows a tridimensional view of the kit associated with the equipment for outdoor fitness 100. Detailed Description of the Invention The present invention will now be described only for exemplificative but non-limitative and non-binding purposes with the help of the Figures, which show some embodiments of the present inventive concept. Referring to FIG.1, it shows some of the preferred embodiments of the equipment for outdoor fitness 100. Always in FIG.1, and in the following description, the embodiments of the present invention are presented which up to now are considered the best ones. Said equipment for outdoor fitness 100 comprises a base 101, a shaped frame 102, a rotatable seat 103, a seat 104 heated by a coil, a handlebar 106, an infographic with QR code 107, and a button 108 for the coil. Said base 101 made of concrete is filled with an adequate material or else with a concrete subjected to bush hammering so as to be antislip; moreover, it is heavier than the remaining of the equipment in order to guarantee its required stability, so that it can be used even in presence of loads with noticeable eccentricity. Said base 101 is connected to a shaped frame 102 having a variable shape. Said shaped frame 102 provides a heated seat with coil 104; said seat with coil 104 is suited to be electrically heated upon pressing the button 108 for the coil. Said shaped frame 102 extends forming extruded parts acting as armrests on each of which a handlebar 106 is mounted, the latter being suited to provide a stable and safe hand grip during the physical activity. On said shaped frame 102 an infographic with QR code 107 is applied, for the purpose of providing a clear and easily readable indication with regard to the best way of using the equipment for outdoor fitness 100, the muscle groups involved, the increase in heart rate and the expected caloric expenditure during its use, and allowing its scanning by means of a mobile device in order to receive more specific indications and demos. Actually, the aforesaid QR code is readable by a dedicated software app which the user has preferably already downloaded and installed on its own personal portable device, in order to obtain videos, tips and information on the correct use of each element of the kit. Always FIG.1 shows another embodiment in which said shaped frame 102 forms a horizontal plane on which a rotary seat 103 is mounted to allow the user to make controlled movements at the level of the lumbar region while maintaining firm the upper part of the body. Said shaped frame 102 forms then a back with extrusions/protrusions for the self-massage 105 adapted to allow the massage of the lumbar zone of the back when the movement with said rotary seat 103 is activated. With reference to FIG. 2 there is shown a kit for said equipment for outdoor fitness 100 according to an embodiment. Said kit will be described with reference to FIG. 1. The kit associated with said equipment for outdoor fitness 100 comprises a totem 200 with a projecting roof 201, a display 202 and a loudspeaker 203, as well as at least one equipment for outdoor fitness 100. Said totem 200 forms the core of the kit, it includes a display 202 with an interactive interface in order to provide information concerning the use of the equipment, the use of the various devices of the equipment, training programs and other useful information. Said display 202 allows interactivity thanks to anti-vandal buttons with braille 205, realized in such a way to facilitate use also for people with limited visual capacity, due to the additional provision of a loudspeaker 203 that communicates in a clear manner all that set forth on video by said display 202. Said totem 200 is provided with a current outlet 204 for recharging mobile devices and is electrically power supplied by a solar panel 207 and the urban power grid through an electrical connection 206 which also connects to said equipment for outdoor fitness 100 in order to provide electric power to the heated seat with coil 108. Said totem 200 and all of its components are produced from a watertight material, which is resistant and impervious, ensuring a good durability over time in combination with the projecting roof 201 adapted to protect said totem 200 from bad weather and provide shading on said display 202 during days of strong sunshine. Finally, it is clear that the invention described above may be modified, and that additions or variants may be made which are obvious for a person skilled in the art, without departing in this way from the protective scope as defined in the appended claims.