Active Engagement (AE) techniques are used to increase the intensity of treatment without increasing the pressure. They integrate active movement by the client with therapeutic techniques by the therapist. In addition, these techniques address multiple issues: chronic tension, overuse injuries, and muscles that are difficult to access. The work is performed during concentric and eccentric muscular contractions. Concentric contraction is the shortening of a muscle. In contrast, an eccentric contraction is the lengthening of a muscle.