An exercise device including at least one positionable component configured to be positioned by a user. The exercise device includes a frame to which a collar is mounted. The positionable component includes a member slidably received within the collar that may be positioned therein by sliding. A locking assembly is coupled to the collar and operable to lock the member in a selected position within the collar, release the member from the locked position, and when released, allow the member to slide within the collar. The locking assembly includes a cam pivotably mounted to the collar and a cam follower assembly selectively biased by the cam against a portion of the member disposed inside the collar. The locking assembly also includes a pair of engagement members disposed inside the collar opposite the cam. The engagement members are moveable relative to one another and biased by the cam against member.