Electromechanical Delay after ACL Reconstruction: An Innovative Method for Investigating Central and Peripheral Contributions

Objectives The purpose of this study was to investigate the electromechanical properties of atrophied muscle in patients with anterior cruciate ligament (ACL) reconstruction and to examine the relationship of changes in these properties for a voluntarily elicited maximal isometric contraction and peripherally stimulated twitch contraction. Background It is not known if, following ACL reconstruction, a prolonged reaction time to a sudden stimulus is due to impaired proprioception in the knee joint, a prolonged processing interval in the central nervous system, or a greater elasticity in the series elastic component of the quadriceps femoris. Methods Seventeen patients were recruited 2 to 3 months following a unilateral ACL reconstruction. Both the involved leg (ACL-invo group) and the uninvolved leg (ACL-uninvo group) were studied. Twenty-two athletes (training group) and 18 control subjects (control group) were also tested. These subjects performed voluntary maximal isometric contraction (MVC) of the quad...