System and methods for actuating an object

A system for actuating an object, comprising:

• an actuator comprising a fluid-pressurizable bladder;
• and a knitted sleeve, the actuator comprising a length, a diameter and a internal volume,
• the knitted sleeve including a plurality of stitches, the knitted sleeve position generally around the fluid-pressurizable bladder, wherein the bladder expands when pressurized causing stitches to move in a sliding motion to decrease the length of the actuator and increase the diameter of the actuator.