This paper presents a study which aim is to examine the adjustments in the neuromuscular control of the knee joint in intact, injured and reconstructed anterior cruciate ligament during dynamic joint stabilization with a knee brace. Surface electromyography (sEMG) and biomechanical data are measured to determine healthy activation patterns and pathological activation patterns. There are significant differences in amplitude of activation and firing between groups. A particular clustering of muscle groups can be seen on both injured and reconstructed patients. Results suggest that reconstruction of ACL leads to a general trend towards normal timing of activation but with mistiming (higher latency) in post-landing activity of knee stabilizers probably due to alteration of the reflex excitability.