A motorized device for training the lower limbs of a subject, the device comprising a pair of articulated systems (ASs) (9, 900), intended to form an interface with said subject, wherein each of said articulated systems comprises a base, a foot support assembly and a framework for said foot support assembly, wherein: - said framework comprises two longitudinal, articulated subassemblies (5, 6), a main subassembly and a supporting subassembly, wherein, at one extremity, said main subassembly is pivotally connected to a first cart articulation, and with the other extremity it is connected to said foot support assembly, wherein said supporting subassembly is pivotally connected at one extremity to a second cart articulation and with the other extremity to said main subassembly; - said base comprises a support or carrier structure (10, 910) on which two rail track sections (11, 12; 13, 14), a first rail track section (11, 12) and a second rail track section (13, 14), are fixed, wherein a first cart is guided on said first rail track section and a second cart is guided on said second rail track section; - said base further comprises a first driving screw and a second driving screw, wherein said first driving screw is arranged to drive said first cart and said second driving screw is arranged to drive said second cart; - a first motor is arranged to rotate said first driving screw and a second motor is arranged to rotate said second driving screw, wherein rotation of said first and second driving screws results in linear movement of said first and second cart, respectively; wherein said motorized device further comprises: - a third motor acting on a transmission assembly, wherein said transmission assembly is adapted to transmit a rotational movement of said third motor to said foot support assembly, wherein said foot support assembly is pivotally connected to said main subassembly, wherein said transmission assembly comprises a plurality of pairs of co-rotational belt pulleys (23, 23'; 24, 24'; 25, 25'; 26, 26') and a plurality of driving belts (27,28,29,33,34) acting on said belt pulleys, characterized in that said third motor is fixed on said first cart and in that a rotational movement from said third motor on said first cart propels the rotation of a motor pulley, and wherein rotation of said motor pulley is transmitted via a first belt to a first pair of pulleys (23, 23') of said transmission assembly. - said framework comprises two longitudinal, articulated subassemblies (5, 6), a main subassembly and a supporting subassembly, wherein, at one extremity, said main subassembly is pivotally connected to a first cart articulation, and with the other extremity it is connected to said foot support assembly, wherein said supporting subassembly is pivotally connected at one extremity to a second cart articulation and with the other extremity to said main subassembly; - said base comprises a support or carrier structure (10, 910) on which two rail track sections (11, 12; 13, 14), a first rail track section (11, 12) and a second rail track section (13, 14), are fixed, wherein a first cart is guided on said first rail track section and a second cart is guided on said second rail track section; - said base further comprises a first driving screw and a second driving screw, wherein said first driving screw is arranged to drive said first cart and said second driving screw is arranged to drive said second cart; - a first motor is arranged to rotate said first driving screw and a second motor is arranged to rotate said second driving screw, wherein rotation of said first and second driving screws results in linear movement of said first and second cart, respectively; wherein said motorized device further comprises: - a third motor acting on a transmission assembly, wherein said transmission assembly is adapted to transmit a rotational movement of said third motor to said foot support assembly, wherein said foot support assembly is pivotally connected to said main subassembly, wherein said transmission assembly comprises a plurality of pairs of co-rotational belt pulleys (23, 23'; 24, 24'; 25, 25'; 26, 26') and a plurality of driving belts (27,28,29,33,34) acting on said belt pulleys, characterized in that said third motor is fixed on said first cart and in that a rotational movement from said third motor on said first cart propels the rotation of a motor pulley, and wherein rotation of said motor pulley is transmitted via a first belt to a first pair of pulleys (23, 23') of said transmission assembly.