title: A physical activity screening measure for use with adolescents in primary care.
abstract: OBJECTIVE
  To develop a reliable and valid physical activity screening measure for use with adolescents in primary care settings.
  
  
  METHODS
  We conducted 2 studies to evaluate the test-retest reliability and concurrent validity of 6 single-item and 3 composite measures of physical activity. Modifications were based on the findings of the 2 studies, and a best measure was evaluated in study 3. Accelerometer data served as the criterion standard for tests of validity.
  
  
  RESULTS
  In study 1 (N = 250; mean age, 15 years; 56% female; 36% white), reports on the composite measures were most reliable. In study 2 (N = 57; mean age, 14 years; 65% female; 37% white), 6 of the 9 screening measures correlated significantly with accelerometer data. Subjects, however, had great difficulty reporting bouts of activity and distinguishing between intensity levels. Instead, we developed a single measure assessing accumulation of 60 minutes of moderate to vigorous physical activity. Evaluated in study 3 (N = 148; mean age, 12 years; 65% female; 27% white), the measure was reliable (intraclass correlation, 0.77) and correlated significantly (r = 0.40, P<.001) with accelerometer data. Correct classification (63%), sensitivity (71%), and false-positive rates (40%) were reasonable.
  
  
  CONCLUSIONS
  The "moderate to vigorous physical activity" screening measure is recommended for clinical practice with adolescents.
authors.affiliation: San Diego State University, 6363 Alvarado Ct, Suite 250, San Diego, CA 92120, USA. prochask@sunstroke.sdsu.edu
authors.forename: J J
authors.initials: JJ
authors.lastname: Prochaska
authors.forename: J F
authors.initials: JF
authors.lastname: Sallis
authors.forename: B
authors.initials: B
authors.lastname: Long
mesh_terms: D000293:Adolescent; D016497:Adolescent Health Services; D002140:California; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008991:Monitoring, Physiologic; D010414:Pennsylvania; D010865:Pilot Projects; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires