8 is mounted on the reflection mirror 9 and lies at the same height as the eyes of an average user during a workout referring to fig1 and fig2 in this embodiment the lat pulldown fitness device 100 further comprises a chip reader 10 disposed on the support frame 73 and electrically connected to the controller 2 the chip reader 10 reads a chip card wherein the chip card stores user profiles and past workout data referring to fig4 and fig5 in this embodiment of the mrf resistance provider 1 the magnetic field generating portion 11 comprises a magnetically permeable body 111 even numbered magnetic poles 112 even numbered magnetically permeable coils 113 even numbered spacers 114 and two first covers 115 this embodiment is exemplified by four magnetic poles 112 four magnetically permeable coils 113 and four spacers 114 the magnetic poles 112 are spaced apart and disposed circumferentially on the magnetically permeable body 111 the magnetically permeable coils 113 are each disposed around a corresponding one of the magnetic poles 112 the spacers 114 each adjoin two magnetic poles 112 to hermetically seal the space between the two magnetic poles 112 the first covers 115 flank the magnetically permeable body 111 the magnetic poles 112 and the spacers 114 so as for the magnetically permeable coils 113 to be hermetically sealed within a space defined jointly by the first covers 115 the magnetic poles 112 and the spacers 114 the shaft 13 is coupled to the magnetically permeable body 111 and sticks out of the first covers 115 and the magnetically permeable external roller 12 bearings are disposed between the first covers 115 of the magnetically permeable external roller 12 and.