title: Low dynamic muscle strength and its associations with fatigue, functional performance, and quality of life in premenopausal patients with systemic lupus erythematosus and low disease activity: a case-control study.
abstract: BACKGROUND
  The purpose of the present study was to compare dynamic muscle strength, functional performance, fatigue, and quality of life in premenopausal systemic lupus erythematosus (SLE) patients with low disease activity versus matched-healthy controls and to determine the association of dynamic muscle strength with fatigue, functional performance, and quality of life in SLE patients.
  
  
  METHODS
  We evaluated premenopausal (18-45 years) SLE patients with low disease activity (Systemic lupus erythematosus disease activity index [SLEDAI]: mean 1.5 ± 1.2). The control (n = 25) and patient (n = 25) groups were matched by age, physical characteristics, and the level of physical activities in daily life (International Physical Activity Questionnaire IPAQ). Both groups had not participated in regular exercise programs for at least six months prior to the study. Dynamic muscle strength was assessed by one-repetition maximum (1-RM) tests. Functional performance was assessed by the Timed Up and Go (TUG), in 30-s test a chair stand and arm curl using a 2-kg dumbbell and balance test, handgrip strength and a sit-and-reach flexibility test. Quality of life (SF-36) and fatigue were also measured.
  
  
  RESULTS
  The SLE patients showed significantly lower dynamic muscle strength in all exercises (leg press 25.63%, leg extension 11.19%, leg curl 15.71%, chest press 18.33%, lat pulldown 13.56%, 1-RM total load 18.12%, P < 0.001-0.02) compared to the controls. The SLE patients also had lower functional performance, greater fatigue and poorer quality of life. In addition, fatigue, SF-36 and functional performance accounted for 52% of the variance in dynamic muscle strength in the SLE patients.
  
  
  CONCLUSIONS
  Premenopausal SLE patients with low disease activity showed lower dynamic muscle strength, along with increased fatigue, reduced functional performance, and poorer quality of life when compared to matched controls.
authors.affiliation: Graduate Program in Medical Sciences, School of Medicine, Universidade de Brasília (UnB), Brasília, Brazil. sandorbalsamo@gmail.com.
authors.forename: Sandor
authors.initials: S
authors.lastname: Balsamo
authors.forename: Licia Maria Henrique
authors.initials: LM
authors.lastname: da Mota
authors.forename: Jozélio Freire
authors.initials: JF
authors.lastname: de Carvalho
authors.forename: Dahan da Cunha
authors.initials: Dda C
authors.lastname: Nascimento
authors.forename: Ramires Alsamir
authors.initials: RA
authors.lastname: Tibana
authors.forename: Frederico Santos
authors.initials: FS
authors.lastname: de Santana
authors.forename: Ricardo Lima
authors.initials: RL
authors.lastname: Moreno
authors.forename: Bruno
authors.initials: B
authors.lastname: Gualano
authors.forename: Leopoldo
authors.initials: L
authors.lastname: dos Santos-Neto
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005221:Fatigue / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D005260:Female; D018737:Hand Strength; D006304:Health Status; D006801:Humans; D016014:Linear Models; D008180:Lupus Erythematosus, Systemic / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D008875:Middle Aged; D053580:Muscle Strength; D017697:Premenopause; D011788:Quality of Life; D011795:Surveys and Questionnaires; D055815:Young Adult