Motor Synergies in Physical Therapy: The Uncontrolled Manifold Approach; A Narrative Review

Movement is the main identity and the base of knowledge and practice in physical therapy; thus, the advances in motor control science, and motor learning and development are linked to physical therapy clinical activity. The purpose of this narrative review article was to describe a prominent approach in motor control with potential to better understanding and diagnosis of movement dysfunctions, the uncontrolled manifold (UCM).

In this narrative review, databases such as PubMed, Web of Science, and Google Scholar were searched from 1999 till 2017, using the key words “Synergy”, “Uncontrolled Manifold”, “Motor Control”, and “Anticipatory Synergy Adjustment”.

Finally, 37 studies were included. Most studies discussed the degree of freedom problem in human movements, history of synergy, characteristics of synergy, introducing the uncontrolled manifold approach as a tool for quantifying the synergy, and clinical applications of this method in the assessments of movement dysfunctions.

Using this method provides the ability to identify the connections between functional activities with motor synergies, synergy strength index, and the anticipatory synergy adjustments. The uncontrolled manifold offers a science-based approach to guide clinical decision making on whether synergies have to be broken, reinforced, or created new synergies in patients with movement dysfunctions.