HAMSTRINGS LENGTH CHANGES DURING DROP JUMP AND SQUAT MANEUVERS

A number of preventive conditioning programs have been developed that attempt to decrease knee ACL injury rates by increasing the strength and control of the muscles of the lower extremity. These programs require specificity of speed, muscle contraction, and lower extremity mechanics (1). Thus, to most effectively condition the lower extremity muscles during sport activities it is important to understand the specific muscle mechanics. Additionally, the hamstring muscle group contributions to knee joint stability during activity have recently been questioned due to high shortening velocities (2). Therefore the purpose of this study is to describe and contrast overall muscle-tendon (M-T) length changes during a slow squat (SS) and a faster drop–jump (DJ) maneuver