title: Physical activity self-monitoring and weight loss: 6-month results of the SMART trial.
abstract: BACKGROUND
  Weight loss has been associated with higher physical activity (PA) levels and frequent dietary self-monitoring. Less is known about how PA self-monitoring affects adherence to PA goals, PA levels, and weight change.
  
  
  METHODS
  The SMART Trial is a clinical weight loss trial in which 210 overweight adults were randomized equally to one of three arms: 1) paper record (PR), 2) personal digital assistant with self-monitoring software (PDA), and 3) PDA with daily tailored feedback message (PDA + FB). PA self-monitoring and adherence to PA goals were based on entries in weekly submitted diaries. PA levels were measured via self-report by the past 6-month Modifiable Activity Questionnaire at baseline and 6 months.
  
  
  RESULTS
  Data are presented on 189 participants with complete 6-month PA data (84% female, 77% white, mean age = 47.3 ± 8.8 yr, mean body mass index = 34.1 ± 4.5 kg·m(-2)). Median PA level was 7.96 MET·h·wk(-1) at baseline and 13.4 MET·h·wk(-1) at 6 months, with significant PA increases in all three arms. PDA + FB arm had a higher mean number of weekly self-monitoring entries than the PR arm (3.4 vs 2.4, P = 0.003) and were more likely to maintain high (i.e., 100%) adherence to PA goals over time than the PDA (P = 0.02) or PR arms (P = 0.0003). Both PA self-monitoring and adherence to PA goals were related to higher PA levels at 6 months. A higher mean rate of PA self-monitoring was associated with a greater percentage of weight decrease (ρ = -0.49, P < 0.0001) at 6 months.
  
  
  CONCLUSIONS
  PA self-monitoring and adherence to PA goals were more likely in participants in the PDA + FB arm and in turn predicted higher PA levels and weight loss.
authors.affiliation: School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA. conroymb@upmc.edu
authors.forename: Molly B
authors.initials: MB
authors.lastname: Conroy
authors.forename: Kyeongra
authors.initials: K
authors.lastname: Yang
authors.forename: Okan U
authors.initials: OU
authors.lastname: Elci
authors.forename: Kelley Pettee
authors.initials: KP
authors.lastname: Gabriel
authors.forename: Mindi A
authors.initials: MA
authors.lastname: Styn
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Kriska
authors.forename: Susan M
authors.initials: SM
authors.lastname: Sereika
authors.forename: Lora E
authors.initials: LE
authors.lastname: Burke
mesh_terms: D000328:Adult; D015992:Body Mass Index; D059026:Diagnostic Self Evaluation; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D009043:Motor Activity / Q000502:physiology*; D050177:Overweight / Q000628:therapy*; D010349:Patient Compliance; D011795:Surveys and Questionnaires; D015431:Weight Loss / Q000502:physiology*