title: Compensatory strategies for muscle weakness during stair ascent in subjects with total knee arthroplasty.
abstract: Subjects with total knee arthroplasty (TKA) exhibit decreased quadriceps and hamstring strength. This may bring about greater relative effort or compensatory strategies to reduce knee joint moments in daily activities. To study gait and map out the resource capacity, knee muscle strength was assessed by maximal voluntary concentric contractions, and whole body kinematics and root mean square (RMS) electromyography (EMG) of vastus lateralis and semitendinosus were recorded during stair ascent in 23 unilateral TKA-subjects ~19 months post-operation, and in 23 healthy controls. Muscle strength and gait velocity were lower in the TKA group, but no significant group differences were found in RMS EMG or forward trunk lean. The results suggest that reduced walking velocity sufficiently compensated for reduced knee muscle strength.
authors.affiliation: Department of Community Medicine & Rehabilitation Physiotherapy, Umeå University, Umeå, Sweden; Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
authors.forename: Joakim
authors.initials: J
authors.lastname: Bjerke
authors.affiliation: Department of Biomedical Engineering & Informatics, Umeå University Hospital, Umeå, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Öhberg
authors.affiliation: Surgical & Perioperative Sciences, Umeå University Hospital, Umeå, Sweden.
authors.forename: Kjell G
authors.initials: KG
authors.lastname: Nilsson
authors.affiliation: Department of Community Medicine & Rehabilitation Physiotherapy, Umeå University, Umeå, Sweden; Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
authors.forename: Ann K
authors.initials: AK
authors.lastname: Stensdotter
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D004576:Electromyography; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology / Q000601:surgery; D007866:Leg / Q000601:surgery; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000601:surgery*; D018482:Muscle, Skeletal / Q000502:physiology* / Q000601:surgery; D052097:Quadriceps Muscle / Q000601:surgery; D016138:Walking
keywords: electromyography; kinematics; maximal voluntary contraction; muscular utilization; stairs