title: Back muscle fatigue of younger and older adults with and without chronic low back pain using two protocols: A case-control study.
abstract: The purpose of this study was to compare back muscle fatigue of younger and older participants with and without chronic low back pain (CLBP). Twenty participants without and 20 with nonspecific CLBP participated in this study. Each group contained 10 younger (50% males; mean age: 31 ± 6 yrs) and 10 older adults (50% males; age mean: 71 ± 7 yrs). Two isometric fatigue protocols were presented randomly: (1) to maintain the unsupported trunk at the horizontal position while on a 45° Roman chair for a minute, and (2) to maintain a 10% of body weight box close to the trunk in the upright position for a minute. Surface electromyography (EMG) signals from the back (multifidus and iliocostalis) and one hip (biceps femoris) muscles were recorded bilaterally, and the median frequency fatigue estimate from linear regression slopes of the EMG time-series was computed. There were no significant (P > 0.05) age effects, and group-by-age interaction in both isometric and functional fatigue tasks. However, the CLBP groups (both younger and old) displayed more back fatigue than people without CLBP in both fatigue protocols (P < 0.01; effect size varying of d = 0.17-0.32). This study was sensitive to discriminate that individuals with CLBP did present significantly more pronounced EMG back fatigue than people without CLBP, in both younger and older adults. These results have significant clinical implications for low back pain rehabilitation programs with regard to endurance assessment in both younger and older.
authors.affiliation: Center for Health Science Research, Laboratory of Functional Evaluation and Human Motor Performance (LAFUP), Universidade Norte do Paraná (UNOPAR), 675 Paris Av, Londrina, PR, Brazil; Doctoral and Masters Program in Rehabilitation Sciences UEL/UNOPAR, 675 Paris Av, Londrina, PR, Brazil. Electronic address: rubens@unopar.br.
authors.forename: Rubens A
authors.initials: RA
authors.lastname: da Silva
authors.affiliation: Florida International University (FIU), Physical Therapy & Neuroscience Departments, Wertheims' Colleges of Nursing and Health Sciences & Medicine, 11200 SW 8th St., AHC3-430, Miami, FL, USA.
authors.forename: Edgar R
authors.initials: ER
authors.lastname: Vieira
authors.affiliation: Universidade Estadual de Londrina (UEL), Rod. Celso Garcia Cid, 445 Km 380, Campus Universitário Londrina, PR, Brazil.
authors.forename: Marcos
authors.initials: M
authors.lastname: Cabrera
authors.affiliation: Universidade Estadual de Londrina (UEL), Rod. Celso Garcia Cid, 445 Km 380, Campus Universitário Londrina, PR, Brazil.
authors.forename: Leandro R
authors.initials: LR
authors.lastname: Altimari
authors.affiliation: Center for Health Science Research, Laboratory of Functional Evaluation and Human Motor Performance (LAFUP), Universidade Norte do Paraná (UNOPAR), 675 Paris Av, Londrina, PR, Brazil; Doctoral and Masters Program in Rehabilitation Sciences UEL/UNOPAR, 675 Paris Av, Londrina, PR, Brazil.
authors.forename: Andreo F
authors.initials: AF
authors.lastname: Aguiar
authors.affiliation: Center for Health Science Research, Laboratory of Functional Evaluation and Human Motor Performance (LAFUP), Universidade Norte do Paraná (UNOPAR), 675 Paris Av, Londrina, PR, Brazil; Doctoral and Masters Program in Rehabilitation Sciences UEL/UNOPAR, 675 Paris Av, Londrina, PR, Brazil.
authors.forename: Alexandre H
authors.initials: AH
authors.lastname: Nowotny
authors.affiliation: Center for Health Science Research, Laboratory of Functional Evaluation and Human Motor Performance (LAFUP), Universidade Norte do Paraná (UNOPAR), 675 Paris Av, Londrina, PR, Brazil; Doctoral and Masters Program in Rehabilitation Sciences UEL/UNOPAR, 675 Paris Av, Londrina, PR, Brazil.
authors.forename: Adriana F
authors.initials: AF
authors.lastname: Carvalho
authors.affiliation: Center for Health Science Research, Laboratory of Functional Evaluation and Human Motor Performance (LAFUP), Universidade Norte do Paraná (UNOPAR), 675 Paris Av, Londrina, PR, Brazil; Doctoral and Masters Program in Rehabilitation Sciences UEL/UNOPAR, 675 Paris Av, Londrina, PR, Brazil.
authors.forename: Marcio R
authors.initials: MR
authors.lastname: Oliveira
mesh_terms: D000328:Adult; D064131:Back Muscles / Q000254:growth & development / Q000502:physiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue
keywords: Aging; EMG; Low back pain; Muscle fatigue