A method of loading a medical device into a delivery system includes providing a two-stage shape memory alloy at a temperature at which at least a portion of the alloy includes austenite. A stress which is sufficient to form R-phase from at least a portion of the austenite is applied to the medical device at the temperature. A delivery configuration of the medical device is obtained, and the medical device is loaded into a restraining member. Preferably, the delivery configuration of the medical device includes stress-induced R-phase.