Telescopically extendable and collapsible ladder assembly having a bottom ladder section, a top ladder section, and one or more intermediate ladder sections, wherein each of the ladder sections (2, 3, 4) comprises two tubular stile members (5, 6), each having a bottom end (5a, 6a) and a top end (5b, 6b), which tubular stile members (5,6) are arranged parallel to each other and are interconnected at the top end by a ladder rung to form a U-shaped ladder section, and wherein the tubular stile members (5,6) of the bottom ladder section are furthermore connected by a bottom ladder rung, wherein the top ladder section and the one or more intermediate ladder sections are collapsible ladder sections, each having the bottom end (5a, 6a) of the tubular style members (5, 6) telescopically inserted into the top end (5b, 6b) of the tubular stile members (5, 6) of an adjacent ladder section, to allow the collapsible ladder section to be moved relative to the adjacent ladder section between a collapsed position and an extended position, wherein the ladder assembly further comprises automatic latch mechanisms for locking the telescopically inserted tubular stile members of the collapsible ladder sections (3, 4) relative to the adjacent ladder sections when the collapsible ladder section are in the extended position, the latch mechanisms being associated with actuators for unlocking the tubular stile members in order to allow for collapsing of the ladder assembly, wherein multiple of said collapsible ladder sections are provided with air dampers, being mounted on the bottom end of the tubular stile members (5, 6) of the collapsible ladder sections (3, 4), wherein the air dampers provide retardation of gravity induced velocity of the collapsible ladder sections (3, 4) upon collapse of the ladder sections on the basis of throttling an airflow flowing from the tubular stile member of the adjacent ladder section into the tubular stile member of the collapsible ladder section during collapse, wherein each of the air dampers comprises: a barrier member, which barrier member is mounted on the bottom end of the tubular stile member (5, 6), which barrier member defines one or more throttle openings that enable air to flow from the tubular stile member of the adjacent ladder section into the tubular stile member of the collapsible ladder section on which the damper member is mounted; a valve member, which valve member is moveable supported relative to the barrier member, such that the valve member can be moved relative to the barrier member between a non-throttle position, in which air can flow through the one or more throttle openings, and a throttle position, in which the valve member at least partially seals off the one or more throttle openings to throttle air flowing from the tubular stile member of the adjacent ladder section into the tubular stile member of the collapsible ladder section on which the damper member is mounted; and an actuator member, characterized in that the actuator member comprises one or more discrete grip pads, which one or more grip pads are each connected to the valve member by a connector arm, and which one or more grip pads are each positioned adjacent the inside surface of the tubular stile member of the adjacent ladder section, and a resilient device that pushes the one or more discrete grip pads against the inside surface such that the grip pads make frictional contact with the inside surface, wherein the actuator member pushes the valve member into the throttle position during collapse of the collapsible ladder section (3, 4), and pushes the valve member into the non-throttle position during extension of the collapsible ladder section (3, 4). a barrier member, which barrier member is mounted on the bottom end of the tubular stile member (5, 6), which barrier member defines one or more throttle openings that enable air to flow from the tubular stile member of the adjacent ladder section into the tubular stile member of the collapsible ladder section on which the damper member is mounted; a valve member, which valve member is moveable supported relative to the barrier member, such that the valve member can be moved relative to the barrier member between a non-throttle position, in which air can flow through the one or more throttle openings, and a throttle position, in which the valve member at least partially seals off the one or more throttle openings to throttle air flowing from the tubular stile member of the adjacent ladder section into the tubular stile member of the collapsible ladder section on which the damper member is mounted; and an actuator member, characterized in that the actuator member comprises one or more discrete grip pads, which one or more grip pads are each connected to the valve member by a connector arm, and which one or more grip pads are each positioned adjacent the inside surface of the tubular stile member of the adjacent ladder section, and a resilient device that pushes the one or more discrete grip pads against the inside surface such that the grip pads make frictional contact with the inside surface,