referring now to the figures of the drawing in detail and first , particularly , to fig1 thereof , there is shown a ski boot according to the invention that preferably has an outer shoe with a relatively thick sole , on which front and rear binding elements act in order to produce the connection to the ski . internally , the ski boot may be provided additionally with cushioning 5 , composed of foam in selected areas , for example adjacent to the rear closure flap 2 , which can be rotated about an axis 19 as shown in fig1 . a plurality of chambers 3 , for example between 10 and 20 , are provided at least in pressure - sensitive areas and are filled with a magnetorheological liquid which preferably has a dynamic viscosity of at least 10 pa · s and solidifies when a magnetic field is applied . it is also possible , but not necessary , for the entire foot area to be enclosed by chambers 3 . fig3 and 4 schematically illustrate devices 30 for producing a magnetic field , which devices are in the form of permanent magnets 8 , with flow links 7 being located in their magnetic fields between the chambers 3 . the chambers are disposed in a plurality of rings one above the other in the ankle part of the boot , so that the closure flap 2 that is provided at the front in this embodiment also has chambers 3 . the permanent magnets 8 are inserted in pockets that extend to the upper edge of the ankle part of the boot , so that they can be rotated or pulled out upwards in order to vary the foot area 1 and to deform the chambers 3 . as soon as the ski boot has been matched to the foot again , the permanent magnets 8 can be rotated back again or pushed in again , as a result of which the magnetorheological liquid circulating in the flow links 7 solidifies again . alternatively , as is shown schematically in fig1 , a magnetic shield 32 can be inserted between the permanent magnets 8 and the flow links 7 . magnetorheological liquid contained in the chambers 3 remains liquid , but cannot move because of the small volume of the chamber 3 , which is blocked by the flow links 7 . as shown in fig1 , the flow links may each have a constriction 29 , so that the solidified magnetorheological liquid forms a plug which surrounds the constriction in an interlocking manner . alternatively or additionally , the inner wall of the flow links 7 may also be uneven or rough . by way of example , the pressure in the chambers 3 can be set conveniently by at least one rotary knob that is not shown , and may also be retained differently , despite subsequent matching with the flow links being influenced in an appropriately variable manner . the chambers 3 may also be composed of a flexible material , which may also be elastic , and , as is illustrated schematically in fig9 , may be provided on one side of a mounting panel 28 or the like . the chambers 3 may be identical or else , as is indicated in fig9 , may have different shapes . the lines 6 and the flow links 7 which are not shown here , are disposed on the other side of the mounting panel 28 and are passed to the chambers 3 through a respective hole . the chambers 3 may also be disposed one above the other in a plurality of , in particular , offset , layers . let us now return to fig1 and 2 , in which the only schematically indicated chambers 3 are associated with the side and front of the foot area 1 , and possibly also with the rear , and / or are in the inner sole 4 . the chambers 3 are connected to one another and to a supply container 14 via lines 6 , which are disposed together with other elements 11 , 12 , 13 , 15 and 16 in the sole , which is normally thick in the case of ski boots . if required , the supply container 14 may itself represent a further chamber . the lines 6 have associated electromagnets , which are not shown , for example in a similar manner to the permanent magnets 8 shown in fig3 and 4 , by which it is possible to vary the capability of the magnetorheological liquid to flow , in the described manner . an electric motor 11 is also schematically indicated in fig1 and , via a drive shaft 13 , operates a piston of a pump 12 , by which the magnetorheological liquid can be forced out of the supply container 14 into the chamber 3 in order to match the foot area 1 to the foot , at least on initial use . when used subsequently , for example if the foot is fitting loosely , there are pressure points or it is uncomfortable , the pressure can be reduced or else increased by the pump 12 . the motor 11 has associated control electronics 15 and an associated energy store 16 , for example a capacitor or a rechargeable battery . by way of example , the pressure can be monitored by at least one sensor , whose signals are processed by the control electronics , thus allowing the ski boot to be automatically matched to the foot . as fig1 shows , the electrical energy which is required for the electromagnets and other electrical loads , for example shoe heating , can also be produced in the ski boot if , for example , a generator 9 which converts vibration movement is provided adjacent to the rear face , with the vibration causing a permanent magnet and an induction coil to be moved relative to one another . the embodiment illustrated schematically in fig1 shows a generator 9 that has two permanent magnets 18 which move linearly with respect to sprung end stops and have two associated induction coils . the electricity that is generated flows via a line 10 to the energy store 16 and to the motor 11 in the shoe sole . in fig2 , which does not show the elements 11 to 16 in the shoe sole in detail , an inclination adjustment device for the ankle part of the boot is disposed adjacent to the front of the boot , with damping in the form of a piston - cylinder unit 17 , which likewise contains a magnetorheological liquid , which is likewise connected via the line 6 to the supply container 14 in the sole , and likewise has an associated device for producing the corresponding field . fig5 shows , schematically , a configuration of the permanent magnet 8 , which is disposed within iron caps 24 , which form two magnet poles , such that it can rotate . in the illustrated position , the magnetic field lines 27 of the magnetic field pass through the area close to the poles . the entire arrangement is associated with a flow link 7 between two chambers 3 such that it is located within the magnetic field lines 27 . when the permanent magnet 8 is rotated through 90 °, for example by an external rotary knob , the magnetic field is moved , and the magnetic field lines run within the two iron caps 24 . the flow link 7 in the area close to the poles is therefore located outside the magnetic field , and the magnetorheological liquid that has been solidified in this are can flow again , so that the liquid can move . a plurality of flow links 7 disposed one behind the other can easily be connected in together if the permanent magnet 8 is in the form of a rod . fig6 shows , schematically , the flow link 7 with a rectangular cross section , which is likewise under the influence of the permanent magnet 8 . the magnetic flux is represented by the magnetic field lines 27 . the two iron caps 24 have a first pole pair 26 and , on the opposite side , a second pole pair . one of the two iron caps 24 has an associated winding 25 . electrical energy can now be supplied in such a way that the magnetic field produced by the permanent magnet 8 is neutralized , and the magnetic flux no longer runs over the first pole pair 26 but over the second pole pair , averted from the flow link 7 . the magnetorheological liquid that has been solidified therein can flow again . this embodiment requires little energy , since such energy need be supplied only to deactivate the permanent magnet 8 . fig7 shows a cut - open oblique view of the flow link 7 and an associated electromagnet 20 . the line 6 that contains the magnetorheological liquid is , for example provided with a cruciform iron core 21 , leaving four flow channels free . a winding 23 surrounds the line 6 , and is itself surrounded by an iron casing 22 . when a voltage is applied to the winding 23 , then the magnetic field solidifies the magnetorheological liquid , and flow is no longer possible . once the current flow is switched off , flow can pass through the link 7 again . fig8 shows , schematically , a parallel arrangement of chambers 3 , to each of which a line 6 is passed from the supply container 14 . the supply container 14 has an associated pump 12 , which is operated by the motor 11 . also , instead of the motor 11 as the power source , the piston of the pump 12 may have an associated schematically shown compression spring or some other pressure generator , possibly also a hand pump or the like . close to the supply container , the flow links 7 , on which the already described constrictions 29 ( fig1 ) are preferably provided , have an associated common device 30 , for example in the form shown in fig1 , in order to produce a magnetic field . on the opposite side of the flow links 7 to the permanent magnets 8 , which flow links 7 preferably have an essentially rectangular or , as shown , trapezoidal cross - sectional shape , fig1 shows a layer 36 composed of a magnetic material , for example an iron plate or an iron sheet , a magnetic film or the like , so that the magnetic field lines 27 are closed , and the flow links 7 pass through at right angles to the flow direction . the strength of the field or of the permanent magnet or magnets 8 can now be varied by inserting a shield 32 between the flow links 7 and the permanent magnets 8 , which can be done by hand or , for example , by a motor drive . this is illustrated on the right - hand side of fig1 , in which the outermost magnetic field lines 27 have already been deflected by the shield and no longer pass through the flow link 7 . in simple terms , the magnetorheological liquid is liquid in the area of the shielded magnetic field lines 27 , and is solidified in the area of the unshielded magnetic field lines . the movement of the shield 32 from the illustrated position leads either to complete opening of the flow link 7 ( insertion in the direction of the arrow ) or to its complete closure ( removal in the opposite direction ). in the embodiment shown in fig1 , the magnetorheological liquid is restricted to the area of the flow link 7 , and is sealed in the line 6 at both ends by a sealing element 31 against the medium which is used in the other areas and , in particular , costs less and / or is lighter . if equalization is intended to take place between the supply container 14 and the chamber 3 , for example in order to dissipate any overpressure which may occur in the chamber 3 as a result of swelling of the foot , then the magnetic field of the device 30 is attenuated or cancelled out , and the excess medium is forced into the line 6 . the magnetorheological liquid can be moved to the right , together with the sealing elements 31 . the appropriate amount of the medium in the line 6 leading to the supply container is pumped back into the supply container . as soon as equalization has been achieved , the magnetic field is produced again , and the magnetorheological liquid in the flow link 7 solidifies . the new state is thus ensured . fig1 shows a block diagram of the major steps for use of the ski boot according to the invention , starting with the opening of the rear flap . the ski boot is then fitted and the rear flap closed and locked . in this case , the locking mechanism ( latching in ) or a sensor ( switch ) ensures secure closure . for example bolts which latch in at the side , velcro strip around the ski boot , buckle , snap - action closure , etc . the user - specific settings are then made , specifically corresponding to the weight , the skiing style ( beginner , normal , sports , cross country ), the piste conditions etc . a “ start ” push button is then operated , resulting in the inner shoe being filled with magnetorheological liquid , so that the inner shoe rests over its entire area on the foot . operation of the on / off switch opens the devices for production of the magnetic field ( mrl valves ) and the pump is activated , feeding the magnetorheological liquid from the reservoir into the inner shoe . in the process , the pressure downstream from the pump is measured by a pressure sensor , and is increased until the desired pressure ( user - specific setting ) is reached . the valves are then automatically closed . subsequently , the ski boot is then matched again , automatically following a time interval , or on operation by the user ( and , for example , the pressure is kept constant ). the comfort when wearing a ski boot according to the invention is considerably improved since the internal shape of the foot area 1 can be varied and can be matched to the foot directly , at least when required , not only by convenient operation by removal and insertion of the permanent magnets , by adjustment of a rotary knob etc ., but also by using electrical energy for operation .