An accumulator comprises a housing connected to a hydraulic system, an elastomeric bladder separating a gas compartment from a fluid compartment, and an anti-extrusion device. A method for operating an accumulator comprises connecting the accumulator to a hydraulic system, injecting an inert gas into a gas compartment to a precharge pressure, moving an anti-extrusion device to prevent a bladder from extruding into the hydraulic system, running the accumulator and the hydraulic system downhole, moving the anti-extrusion device to allow fluid communication between the hydraulic system and a fluid compartment, generating pressure fluctuations within the hydraulic system, and expanding or contracting the bladder in response to the pressure fluctuations without moving the anti-extrusion device. A method of improving fluid hammer performance comprises connecting the fluid hammer to an accumulator that produces a greater delivered horsepower from the fluid hammer as compared to a baseline horsepower when operating without the accumulator.