This paper presents a contribution to the field of the musician/instrument interaction analysis. This study aims at investigating the mechanical parameters that govern the harp plucking action as well as the gestural strategies set up by harpists to control a musical performance. Two specific experimental procedures have been designed to accurately describe the harpist motion in realistic playing contexts. They consist in filming the plucking action and the harpists gestures using a high-speed camera and a motion capture system, respectively. Simultaneously, acoustical measurements are performed to relate the kinematic investigation to sound features. Results describe the musical gesture characteristics. Mechanical parameters governing the finger/string interaction are highlighted and their influence on the produced sound are discussed. Besides, the relationship between non sound-producing gestures and musical intent is pointed out. Finally, the way energy is shared between harpist arm joints according to various playing techniques is analyzed.