title: Validating two self-report physical activity measures in middle-aged adults completing a group exercise or home-based physical activity program.
abstract: OBJECTIVE
  To compare self-reported physical activity recorded in physical activity diaries or the Active Australia Survey with objectively measured physical activity using accelerometry in sedentary middle-aged adults completing two physical activity interventions.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Sedentary 50-65 year olds were recruited to a non-randomized 6-month community group exercise program (G) or a physiotherapist-led home-based physical activity program (HB). Over 7-days, 76 participants (HB 39, G 37) wore an ActiGraph GT1M accelerometer (5s epochs), completed the Active Australia Survey (AAS) and a daily physical activity diary. Data were analysed using descriptive statistics and Spearman rank-order correlations.
  
  
  RESULTS
  The two interventions had similar demographic and physical activity characteristics except that home-based participants were younger (p < 0.01), more likely to be employed full time (p ≤ 0.001) and reported less moderate-to-vigorous physical activity in the physical activity diaries compared to group exercise participants (HB 29 ± 21 min d(-1) vs. G 57 ± 35 min d(-1), p ≤ 0.001). Home-based participants had fair-to-good agreement between the physical activity diaries and AAS or ActiGraph data (r = 0.39-0.68, p < 0.05). Group exercise physical activity diary data did not correlate significantly with either the AAS or ActiGraph data. In contrast, group exercise AAS data had good correlations with ActiGraph data (r = 0.49-0.64, p ≤ 0.001).
  
  
  CONCLUSIONS
  Physical activity diaries should be interpreted cautiously unless intervention participants have an adequate understanding of physical activity intensity. The AAS is the preferred self-report measure in middle-aged adults independent of intervention.
authors: Faculty of Health, University of Canberra, ACT 2601, Australia. Electronic address: u3033443@uni.canberra.edu.au.
authors: Nicole
authors: N
authors: Freene
authors: Physiotherapy, Faculty of Health, University of Canberra, ACT 2601, Australia.
authors: Gordon
authors: G
authors: Waddington
authors: Physiotherapy, Faculty of Health, University of Canberra, ACT 2601, Australia.
authors: Wendy
authors: W
authors: Chesworth
authors: Centre for Research & Action in Public Health, Faculty of Health, University of Canberra, ACT 2601, Australia.
authors: Rachel
authors: R
authors: Davey
authors: Centre for Research & Action in Public Health, Faculty of Health, University of Canberra, ACT 2601, Australia.
authors: Tom
authors: T
authors: Cochrane
mesh_terms: D061725:Accelerometry; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D057566:Self Report
keywords: Accelerometer; Diary; Intervention study; Physical activity; Questionnaire; Validation study