title: Validity of linear encoder measurement of sit-to-stand performance power in older people.
abstract: OBJECTIVE
  To investigate construct validity of linear encoder measurement of sit-to-stand performance power in older people by showing associations with relevant functional performance and physiological parameters.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Movement laboratory of a geriatric rehabilitation clinic.
  
  
  METHODS
  Eighty-eight community-dwelling, cognitively unimpaired older women (mean age 78 years).
  
  
  METHODS
  Sit-to-stand performance power and leg power were assessed using a linear encoder and the Nottingham Power Rig, respectively. Gait speed was measured on an instrumented walkway. Maximum quadriceps and hand grip strength were assessed using dynamometers. Mid-thigh muscle cross-sectional area of both legs was measured using magnetic resonance imaging.
  
  
  RESULTS
  Associations of sit-to-stand performance power with power assessed by the Nottingham Power Rig, maximum gait speed and muscle cross-sectional area were r=0.646, r=0.536 and r=0.514, respectively. A linear regression model explained 50% of the variance in sit-to-stand performance power including muscle cross-sectional area (p=0.001), maximum gait speed (p=0.002), and power assessed by the Nottingham Power Rig (p=0.006).
  
  
  CONCLUSIONS
  Construct validity of linear encoder measurement of sit-to-stand power was shown at functional level and morphological level for older women. This measure could be used in routine clinical practice as well as in large-scale studies.
  
  
  BACKGROUND
  DRKS00003622.
authors: Department of Clinical Gerontology and Rehabilitation, Robert-Bosch-Hospital, Stuttgart, Germany. Electronic address: ulrich.lindemann@rbk.de.
authors: U
authors: U
authors: Lindemann
authors: Medical Department 4, Internal Medicine, Rheumatology, Osteology & Westgerman Osteoporosis Centre, Klinikum Leverkusen, Leverkusen, Germany; Department of Nephrology, Justus-Liebig University, Giessen, Germany.
authors: P
authors: P
authors: Farahmand
authors: Department of Clinical Gerontology and Rehabilitation, Robert-Bosch-Hospital, Stuttgart, Germany; Institute of Epidemiology, Ulm University, Ulm, Germany.
authors: J
authors: J
authors: Klenk
authors: Department of Radiology and Nuclear Medicine, Robert-Bosch-Hospital, Stuttgart, Germany.
authors: K
authors: K
authors: Blatzonis
authors: Department of Clinical Gerontology and Rehabilitation, Robert-Bosch-Hospital, Stuttgart, Germany.
authors: C
authors: C
authors: Becker
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D005684:Gait / Q000502:physiology; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D053580:Muscle Strength / Q000502:physiology; D026741:Physical Therapy Modalities / Q000592:standards*; D052097:Quadriceps Muscle / Q000502:physiology; D015203:Reproducibility of Results
keywords: Construct validity; Older women; Power; Sit-to-stand