Abstract: An article of clothing including a piezoelectric transducer and an electrical component restrains movement of a first body portion relative to a second body portion. The article of clothing can be a sports bra that controls the wearer's breast movement relative to the wearer's torso. As the breast moves, the piezoelectric transducer deforms and induces a voltage that is passed to the electrical component. The electrical component provides either a resistance or a control signal to the transducer. The transducer stiffens in response to the electrical component and reduces the movement of the breast by placing an external force on the breast.