A device for aiding plantar flexor muscles comprises at least one actuation mechanism (10) comprising a linear actuation element (26), a locking mechanism (25) with an annular toothed surface coupled to the linear actuation element, a retractable rotary element comprising a toothed drum (24) and an elastic spiral element (23), wherein the toothed drum has an annular groove and the toothed drum interacts with the toothed locking mechanism； a string (28) wound around the annular groove in the toothed drum and having an end joined to the elastic element (2), and a case (21, 27) containing the elements of the actuation mechanism； a control system designed to send a signal to the linear actuation element to activate or deactivate the locking mechanism, and a battery to supply energy to the control system. The technical effect involved is that the lightweight actuation mechanism, together with the lightweight structure, allows the elastic element to store mechanical energy during the dorsal flexion movement, this energy subsequently assisting the plantar flexion movement in order to increase physical performance during long and arduous walks and to reduce user fatigue.El dispositivo asistencial para músculos de flexión plantar comprende al menos un mecanismo de accionamiento (10) comprende un actuador con accionamiento lineal (26)； un mecanismo tipo traba (25) que posee una superficie anular dentada acoplado al accionamiento lineal； un elemento giratorio retráctil compuesto por un tambor dentado (24) y un elemento espiral elástico (23)； en donde el tambor dentado posee una hendidura anular y en donde el tambor dentado se corresponde con el mecanismo tipo traba dentado； una cuerda (28) enrollada en la hendidura anular del tambor dentado con un extremo unido al elemento elástico (2), y una carcasa (21, 27) para contener los elementos del mecanismo de accionamiento； un sistema de control configurado para enviar una señal al actuador con accionamiento lineal para activar o de
