Muscle training device comprising: - a support structure, consisting of: - static elements, attachable to an external fixed structure, and - dynamic elements, - at least one puller that can be moved and operated by a user; - a resistant element linked to the support structure, which exerts a resistance to at least one puller for the performance of a muscular exercise; - fixed pulleys linked to the support structure; - a hoist linked to the support structure and the resistant element; and - a closed cable, without free ends and not anchored to the support structure, linked to the resistant element and to the supporting structure through the fixed pulleys and the hoist and operable by means of at least one puller, such as to allow at least two degrees of freedom of displacement and/or rotation in the puller; the device being characterised in that: - the static elements comprise two vertical central pillars, and two lateral pillars, parallel to the central pillars; and - the dynamic elements comprise: - at least one drive arm simultaneously movable along one central pillar and one lateral pillar; - at least one carriage movable along each arm, to which at least one puller is attached; and - a slide linked to the at least one drive arm and the corresponding lateral pillar, so that the at least one drive arm can slide along the corresponding central pillar and the corresponding lateral pillar. - a support structure, consisting of: - static elements, attachable to an external fixed structure, and - dynamic elements, - static elements, attachable to an external fixed structure, and - dynamic elements, - at least one puller that can be moved and operated by a user; - a resistant element linked to the support structure, which exerts a resistance to at least one puller for the performance of a muscular exercise; - fixed pulleys linked to the support structure; - a hoist linked to the support structure and the resistant element; and - a closed cable, without free ends and not anchored to the support structure, linked to the resistant element and to the supporting structure through the fixed pulleys and the hoist and operable by means of at least one puller, such as to allow at least two degrees of freedom of displacement and/or rotation in the puller; - the static elements comprise two vertical central pillars, and two lateral pillars, parallel to the central pillars; and - the dynamic elements comprise: - at least one drive arm simultaneously movable along one central pillar and one lateral pillar; - at least one carriage movable along each arm, to which at least one puller is attached; and - a slide linked to the at least one drive arm and the corresponding lateral pillar, so that the at least one drive arm can slide along the corresponding central pillar and the corresponding lateral pillar. - at least one drive arm simultaneously movable along one central pillar and one lateral pillar; - at least one carriage movable along each arm, to which at least one puller is attached; and - a slide linked to the at least one drive arm and the corresponding lateral pillar, so that the at least one drive arm can slide along the corresponding central pillar and the corresponding lateral pillar.