Scientific Rationale and Physiological Basis for the Use of Closed Kinetic Chain Exercise in the Lower Extremity

Closed kinetic chain exercise is a common component of lower extremity rehabilitation. It has virtually replaced open kinetic chain exercise in the treatment of some conditions. In this paper, anatomy and physiology as they relate to closed chain exercise are examined to elucidate its unique contributions to rehabilitation. Claims made about the specificity, functionality, and safety of closed kinetic chain exercise are discussed. Muscle action, the stretch–shortening cycle, joint position sense, and clinical cases are used to illustrate the distinct role of closed kinetic chain exercise in rehabilitation.