title: Leg extension power asymmetry and mobility limitation in healthy older women.
abstract: OBJECTIVE
  To investigate the association of asymmetry in leg extension power (LEP) with walking and standing balance.
  
  
  METHODS
  Cross-sectional analysis.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Healthy female twins (N=419), ages 63 to 75 years.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  The LEP difference between the stronger and the weaker leg, measured with the Nottingham power rig, was calculated. Ten-meter maximal walking velocity was assessed in a laboratory corridor on a wide (170 cm) and narrow (35 cm) track, and the ability to maintain tandem stance for 20 seconds was recorded.
  
  
  RESULTS
  The mean LEP difference +/- standard deviation between the legs was 15%+/-9% (P<.001). Those with large LEP difference had lower walking velocity and poorer standing balance than those with small LEP difference, in particular when the LEP of the stronger leg was below the median.
  
  
  CONCLUSIONS
  Even in healthy older women, substantial LEP asymmetry between the lower limbs was present, encumbering walking and standing balance. Lower-limb muscle power asymmetry warrants further study in order to develop well-targeted strategies for preventing mobility limitation in older people.
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Jyväskylä.
authors.forename: Erja
authors.initials: E
authors.lastname: Portegijs
authors.forename: Sarianna
authors.initials: S
authors.lastname: Sipilä
authors.forename: Markku
authors.initials: M
authors.lastname: Alen
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
authors.forename: Markku
authors.initials: M
authors.lastname: Koskenvuo
authors.forename: Kristina
authors.initials: K
authors.lastname: Tiainen
authors.forename: Taina
authors.initials: T
authors.lastname: Rantanen
mesh_terms: D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000502:physiology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology; D009142:Musculoskeletal Physiological Phenomena; D010809:Physical Fitness; D004856:Postural Balance / Q000502:physiology*; D011336:Probability; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values; D012680:Sensitivity and Specificity; D014427:Twins; D016138:Walking