title: Muscle co-contraction during gait in individuals with articular cartilage defects in the knee.
abstract: Increased muscle co-contraction during gait is common in individuals with knee pathology, and worrisome as it is known to amplify tibiofemoral compressive forces. While knees with articular cartilage defects (ACD) are more vulnerable to compressive forces, muscle co-contraction has never been reported in this population. The purpose of this study was to evaluate the extent to which individuals with ACDs in the knee demonstrate elevated quadriceps to hamstrings muscle co-contraction on the involved limb during gait compared to the uninvolved limb and to healthy controls. We also explored the impact of participant characteristics and knee impairments on co-contraction. Twenty-nine individuals with full-thickness knee ACDs (ACD group) and 19 healthy adults (control group) participated in this study. Participants performed five gait trials at self-selected speed, during which activity of the quadriceps and hamstrings muscles were collected with surface electromyography. Three-dimensional motion capture was used to define phases of gait. Quadriceps strength and self-reported outcomes were also assessed in the same session. There were no differences in quadriceps: hamstrings co-contraction between the ACD and control groups, or between the involved and uninvolved limb for the ACD group. For both ACD and control groups, co-contraction was highest in early stance and lowest in late stance. Quadriceps strength was consistently the strongest predictor of muscle co-contraction in both the ACD and the control groups, with individuals with lower strength demonstrating greater co-contraction. Further study is needed to understand the effect of increased muscle co-contraction on joint compressive forces in the presence of varied quadriceps strength.
authors.affiliation: Department of Physical Therapy, University of Delaware, Newark, DE, United States.
authors.forename: Louise M
authors.initials: LM
authors.lastname: Thoma
authors.affiliation: School of Health and Rehabilitation Sciences, College of Medicine, The Ohio State University, Columbus, OH, United States.
authors.forename: Michael P
authors.initials: MP
authors.lastname: McNally
authors.affiliation: School of Health and Rehabilitation Sciences, College of Medicine, The Ohio State University, Columbus, OH, United States; Division of Physical Therapy, School of Health and Rehabilitation Sciences, College of Medicine, The Ohio State University, Columbus, OH, United States; Department of Orthopedics, The Ohio State University, Columbus, OH, United States; Department of Mechanical and Aerospace Engineering, College of Engineering, The Ohio State University, Columbus, OH, United States.
authors.forename: Ajit M
authors.initials: AM
authors.lastname: Chaudhari
authors.affiliation: OSU Sports Medicine, The Ohio State University, Columbus, OH, United States; Department of Orthopedics, The Ohio State University, Columbus, OH, United States.
authors.forename: David C
authors.initials: DC
authors.lastname: Flanigan
authors.affiliation: OSU Sports Medicine, The Ohio State University, Columbus, OH, United States; Department of Family Medicine, The Ohio State University, Columbus, OH, United States.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Best
authors.affiliation: School of Health and Rehabilitation Sciences, College of Medicine, The Ohio State University, Columbus, OH, United States; Department of Orthopedics, The Ohio State University, Columbus, OH, United States; Department of Mechanical and Aerospace Engineering, College of Engineering, The Ohio State University, Columbus, OH, United States.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Siston
authors.affiliation: School of Health and Rehabilitation Sciences, College of Medicine, The Ohio State University, Columbus, OH, United States; Division of Physical Therapy, School of Health and Rehabilitation Sciences, College of Medicine, The Ohio State University, Columbus, OH, United States. Electronic address: Laura.Schmitt@osumc.edu.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Schmitt
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000293:injuries*; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D005684:Gait / Q000502:physiology*; D000070633:Hamstring Muscles / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D052097:Quadriceps Muscle / Q000502:physiology
keywords: Chondral defects; Electromyography; Quadriceps strength