Methods of operating a fluid-based spring counterbalance mechanism for a movable barrier are used to support a portion of the weight of the movable barrier. A jackshaft is configured to be operatively coupled to the movable barrier such that rotation of the jackshaft raises or lowers the movable barrier. The jackshaft is operatively coupled to a rotatable input shaft of the fluid-based spring counterbalance mechanism. The rotatable input shaft is coupled to a flexible-walled fluid-based spring. Applying a first force by a movable barrier operator changes the position of the movable barrier, and the flexible-walled fluid-based spring exerts a second force that supports a portion of the weight of the movable barrier in addition to the first force.