title: Is chair rise performance a useful measure of leg power?
abstract: OBJECTIVE
  Chair rise performance, which is simple to assess in a home or clinic setting, has been used as a method of predicting leg power deficit in older adults. More recently, chair rise performance has been assessed in younger populations as a baseline for assessment of subsequent age-related declines in function and power. However, as rising from a chair repeatedly not only requires lower limb strength and power but also good balance and coordination, it may not be purely a measure of leg power especially among these younger, well functioning groups who are yet to experience agerelated declines and deficits in function. The aim of this study was to assess whether chair rise performance can be considered as a predictor of leg power, and hence of deficits in this, in men and women in mid-life. We assessed the relationship of chair rise performance with leg extensor power (LEP), measured using the Nottingham Power Rig (NPR), and with standing balance performance.
  
  
  METHODS
  LEP was measured in a clinic setting in a sub-sample of 81 men and 93 women from the MRC National Survey of Health and Development, a nationally representative cohort born in Britain in 1946. The time taken to rise from a chair 10 times and standing balance time were assessed during home visits at the same age.
  
  
  RESULTS
  Increasing LEP was associated with better chair rise performance among those who completed 10 chair rises in ≥15 seconds, after adjustment for body size (p=0.008). Better standing balance performance was associated with better chair rise performance in men, but not women.
  
  
  CONCLUSIONS
  That LEP and standing balance are both related to chair rise time in men suggests that chair rise time should not be thought of purely as a proxy measure of leg power in middle-aged populations. This has implications for longitudinal studies which want to study age-related decline in chair rise performance.
authors.affiliation: MRC Unit for Lifelong Health and Ageing, Division of Population Health, University College London, UK. r.hardy@nshd.mrc.ac.uk
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hardy
authors.forename: Rachel
authors.initials: R
authors.lastname: Cooper
authors.forename: Imran
authors.initials: I
authors.lastname: Shah
authors.forename: Stephen
authors.initials: S
authors.lastname: Harridge
authors.forename: Jack
authors.initials: J
authors.lastname: Guralnik
authors.forename: Diana
authors.initials: D
authors.lastname: Kuh
mesh_terms: D015331:Cohort Studies; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D004856:Postural Balance; D011446:Prospective Studies; D013997:Time Factors