title: Electromyography and economy of walking in chronic heart failure and heart transplant patients.
abstract: Background Patients with chronic heart failure frequently report intolerance to exercise and present with changes in walk pattern, but information about heart transplant patients is lacking. Alterations of the gait pattern are related to interaction changes between the metabolism, neurological system and the mechanical demands of the locomotor task. The aim of this study was to investigate the electromyographic cost, coactivation and cost of transport of walking of chronic heart failure and heart transplant patients. Design This research was of an exploratory, cross-sectional design. Methods Twelve chronic heart failure patients, twelve healthy controls and five heart transplant patients participated in the study. Electromyographic data and oxygen uptake were collected simultaneously at five walking speeds. Results In the experimental groups, the electromyographic cost, percentage of coactivation in the leg and cost of transport were higher than in controls. The electromyographic cost was in line with the cost of transport. The minimum electromyographic cost matched with the self-selected walking speed in controls, while in chronic heart failure and heart transplant patients, it was reached at speeds higher than the self-selected walking speed. Conclusion The largest postural isometric activation and antagonist activation resulted in the highest metabolic demand. These findings are of great clinical relevance because they support the concept that interventions in order to improve the muscle performance in these patients can increase the self-selected walking speed and therefore the metabolic economy of walking.
authors.affiliation: 1 Exercise Pathophysiology Research Laboratory, Cardiology Division, Hospital de Clínicas de Porto Alegre, UFRGS, Brazil.|2 Biomechanics Research and Movement Analyses Laboratory, CENUR-L.N. Paysandú, Universidad de la República, Uruguay.
authors.forename: Renata L
authors.initials: RL
authors.lastname: Bona
authors.affiliation: 2 Biomechanics Research and Movement Analyses Laboratory, CENUR-L.N. Paysandú, Universidad de la República, Uruguay.|3 Exercise Research Laboratory, School of Physical Education, UFRGS, Brazil.
authors.forename: Artur
authors.initials: A
authors.lastname: Bonezi
authors.affiliation: 1 Exercise Pathophysiology Research Laboratory, Cardiology Division, Hospital de Clínicas de Porto Alegre, UFRGS, Brazil.
authors.forename: Paula Figueiredo da
authors.initials: PF
authors.lastname: Silva
authors.affiliation: 2 Biomechanics Research and Movement Analyses Laboratory, CENUR-L.N. Paysandú, Universidad de la República, Uruguay.
authors.forename: Carlo M
authors.initials: CM
authors.lastname: Biancardi
authors.affiliation: 3 Exercise Research Laboratory, School of Physical Education, UFRGS, Brazil.
authors.forename: Flávio Antônio de Souza
authors.initials: FA
authors.lastname: Castro
authors.affiliation: 4 Department of Medicine, Faculty of Medicine, UFRGS, Brazil.
authors.forename: Nadine Oliveira
authors.initials: NO
authors.lastname: Clausel
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D004576:Electromyography; D004734:Energy Metabolism / Q000502:physiology; D005080:Exercise Test / Q000379:methods; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000534:rehabilitation / Q000601:surgery; D016027:Heart Transplantation / Q000379:methods* / Q000534:rehabilitation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D012016:Reference Values; D016138:Walking / Q000502:physiology; D000072797:Walking Speed / Q000502:physiology*
keywords: Electromyographic cost; coactivation; cost of transport; heart disease