title: Lower limb antagonist muscle co-activation and its relationship with gait parameters in cerebellar ataxia.
abstract: Increased antagonist muscle co-activation, seen in motor-impaired individuals, is an attempt by the neuromuscular system to provide mechanical stability by stiffening joints. The aim of this study was to investigate the co-activation pattern of the antagonist muscles of the ankle and knee joints during walking in patients with cerebellar ataxia, a neurological disease that strongly affects stability. Kinematic and electromyographic parameters of gait were recorded in 17 patients and 17 controls. Ankle and knee antagonist muscle co-activation indexes were measured throughout the gait cycle and during the sub-phases of gait. The indexes of ataxic patients were compared with those of controls and correlated with clinical and gait variables. Patients showed increased co-activity indexes of both ankle and knee muscles during the gait cycle as well as during the gait sub-phases. Both knee and ankle muscle co-activation indexes were positively correlated with disease severity, while ankle muscle co-activation was also positively correlated with stance and swing duration variability. Significant negative correlations were observed between the number of self-reported falls per year and knee muscle co-activation. The increased co-activation observed in these cerebellar ataxia patients may represent a compensatory strategy serving to reduce gait instability. Indeed, this mechanism allows patients to reduce the occurrence of falls. The need for this strategy, which results in excessive muscle co-contraction, increased metabolic costs and cartilage degeneration processes, could conceivably be overcome through the use of supportive braces specially designed to provide greater joint stability.
authors.affiliation: Fondazione Don Gnocchi, Milan, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Mari
authors.forename: Mariano
authors.initials: M
authors.lastname: Serrao
authors.forename: Carlo
authors.initials: C
authors.lastname: Casali
authors.forename: Carmela
authors.initials: C
authors.lastname: Conte
authors.forename: Giovanni
authors.initials: G
authors.lastname: Martino
authors.forename: Alberto
authors.initials: A
authors.lastname: Ranavolo
authors.forename: Gianluca
authors.initials: G
authors.lastname: Coppola
authors.forename: Francesco
authors.initials: F
authors.lastname: Draicchio
authors.forename: Luca
authors.initials: L
authors.lastname: Padua
authors.forename: Giorgio
authors.initials: G
authors.lastname: Sandrini
authors.forename: Francesco
authors.initials: F
authors.lastname: Pierelli
mesh_terms: D000058:Accidental Falls; D000328:Adult; D000368:Aged; D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D002524:Cerebellar Ataxia / Q000175:diagnosis / Q000503:physiopathology*; D018450:Disease Progression; D004576:Electromyography; D005260:Female; D005684:Gait; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D057566:Self Report; D013997:Time Factors