An article of footwear comprising: a bladder; a reservoir; an electronically controlled valve having a fluid port in fluid communication with the bladder and a fluid port in fluid communication with the reservoir; a pressure sensor configured to output bladder pressure values; and an electronic control unit configured to receive information from the pressure sensor and to iteratively open the valve to permit transfer of the one or more gases to the bladder from the reservoir, or from the bladder to the reservoir, until a target bladder pressure is reached.