The present disclosure relates to an apparatus for simulating insertion of an elongated instrument attached to a tether into a structure. The apparatus comprises a casing having an aperture for receiving a distal end of the tether therethrough. The apparatus has a pulley having an outer tether receiving groove on a peripheral portion and an anchoring element therein for anchoring the distal end of the tether, the pulley rotating according to a longitudinal translation of the tether relatively to the casing. The apparatus has a sensing arrangement for sensing an angular position of the pulley representative of a relative longitudinal position of the elongated instrument. The apparatus has a feedback force actuator for applying an adjustable resistive force to a rotation of the pulley according to the sensed angular position and resistance characteristics of the structure. The present disclosure also relates to a medical insertion simulator comprising such an apparatus.