Knee Stability and Movement Coordination Impairments: Knee Ligament Sprain: Clinical Practice Guidelines Linked to the International Classification of Functioning, Disability, and Health from the Orthopaedic Section of the American Physical Therapy Association

. Author manuscript; available in PMC: 2011 Aug 21.

Published in final edited form as: J Orthop Sports Phys Ther. 2010 Apr;40(4):A1–A37. doi: 10.2519/jospt.2010.0303

I	Evidence obtained from high-quality diagnostic studies, prospective studies, or randomized controlled trials
II	Evidence obtained from lesser-quality diagnostic studies, prospective studies, or, randomized controlled trials (eg, weaker diagnostic criteria and reference standards, improper randomization, no blinding, <80% follow-up)
III	Case controlled studies or retrospective studies
IV	Case series
V	Expert opinion