The present invention is an adjustable leg exercise apparatus for allowing a user to perform a leg exercise while sitting on a sitting structure, or alternatively, when standing in a modified standing position. In a first embodiment, the adjustable leg exercise apparatus includes a foot engagement member; a knee-thigh engagement member; at least one elastic resistance member; at least one foot securing mechanism for securing or locking the foot engagement member to the at least one elastic resistance member; at least one knee-thigh securing mechanism for securing or locking the knee-thigh engagement member to the at least one elastic resistance member; and a plurality of length adjustment and securing devices for securing each of the at least one elastic resistance member in any one of a plurality of predetermined adjustment positions. In a second embodiment, the knee-thigh engagement member may include a knee-thigh wrapping device.