A novel ankle gapping device includes a lower leg engaging apparatus, a foot engaging apparatus, and a biasing member disposed between the lower leg engaging apparatus and the foot engaging apparatus. The leg engaging apparatus is adapted to securely engage a user's leg such that the leg engaging apparatus will remain stationary when the biasing member exerts an upward force thereon. The foot engaging apparatus is contoured to fit the user's foot. In a particular embodiment, the biasing member is a pneumatic biasing member, such as an inflatable tube that is actuated by a pump. As the pump provides compressed air (or some other fluid) to the biasing member, the pressure inside the biasing member increases, causing an increase in the volume of the biasing member. This pressure and volume increase exerts an upward force via the leg engaging apparatus to the lower leg, and a downward force via the foot engaging apparatus to the foot. The forces applied to the leg and the foot cause separation of the ankle joint, allowing the synovial fluid to flow over the articulating surfaces of the bones of the joint.