title: Determination of young adults' sedentary time with a multisensory activity monitor and activity log diary.
abstract: BACKGROUND
  Quantification of sedentary time still remains a challenge.
  
  
  OBJECTIVE
  This study examined: 1) whether a multisensory activity monitor could accurately measure sedentary activities and discriminate them from light intensity activities; and 2) the validity of activity log diary (AL) in estimating sedentary time using the monitor as a criterion measure.
  
  
  METHODS
  Thirty healthy individuals performed sedentary and light intensity activities in a laboratory while being equipped with a metabolic measurement cart (MMC) and the multisensory monitor. Subsequently, a subset of 19 participants completed AL while wearing the monitor for three days under free-living conditions.
  
  
  RESULTS
  Metabolic equivalents (METs) measured by the multisensory monitor during sedentary activities were similar to those measured by MMC and were significantly lower than light-intensity activities (p < 0.001). Relative criterion validity of AL assessed by Pearson's correlation coefficient was high (r = 0.68, p < 0.01). Absolute criterion validity examined by Bland-Altman plots showed small mean difference between AL and the monitor (36.9 minutes ⋅ day(-1)) with its limits of agreement ranging from -103.3 to 177.1 minutes ⋅ day(-1).
  
  
  CONCLUSIONS
  The multisensory monitor is capable of accurately measuring sedentary activities and distinguishing them from light-intensity activities. Compared to the multisensory monitor, our results showed that AL provides valid estimate of overall sedentary time.
authors.affiliation: Faculty of Physical Education & Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Tasuku
authors.initials: T
authors.lastname: Terada
authors.affiliation: Faculty of Kinesiology, University of New Brunswick, Fredericton, New Brunswick, Canada.
authors.forename: James R
authors.initials: JR
authors.lastname: Sexsmith
mesh_terms: D056044:Actigraphy / Q000295:instrumentation*; D000328:Adult; D001837:Body Weights and Measures; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D055686:Metabolic Equivalent; D015203:Reproducibility of Results; D057185:Sedentary Behavior; D055815:Young Adult
keywords: Validity; accelerometer; sedentary behavior; self-report