An inflatable structure includes a top end cap, a bottom end cap, a bladder, a plurality of tethers, and an adjustment mechanism. The bladder is attached to the top and bottom end caps and configured to hold pressurized air therebetween. The plurality of tethers are disposed within the bladder. Each tether in the plurality of tethers has a first end coupled to the top end cap and a second end coupled to the bottom end cap. When the bladder is inflated, the plurality of tethers restrict a number of degrees of freedom of the inflatable structure and a type of the degrees of freedom. The adjustment mechanism is operable to move the second end of at least one tether in the plurality of tethers to adjust at least one of the number of the degrees of freedom and the type of the degrees of freedom.