title: Physical activity for bone health in inactive teenage girls: is a supervised, teacher-led program or self-led program best?
abstract: OBJECTIVE
  To investigate the effect of a six-month teacher-led osteogenic physical activity program, vs. a self-led activity program, on ultrasound measurements of bone in inactive teenage girls.
  
  
  METHODS
  Ninety sedentary girls [mean (SD) age 16.3 (.6) years] were identified from 300 assessed for physical activity across five schools in southeast Ireland. Schools were matched and randomly assigned to a teacher-led physical activity (TLPA) program, a self-led physical activity (SLPA) program, or a control group. Broadband ultrasound attenuation (BUA), speed of sound (SOS), and os calcis stiffness index (OCSI) were measured using a portable ultrasound machine. Anthropometry, aerobic fitness, calcium intake, and physical activity were assessed, and focus groups held one month after program completion. Descriptive statistics, paired t-tests, and analysis of variance were used to analyze the data.
  
  
  RESULTS
  Both intervention groups demonstrated significant improvements (p < .05) in BUA, SOS, OCSI and aerobic fitness, i.e., TLPA: +14.9%, +21.9%, + 15.9%, and +8.5%, respectively, and SLPA: +10.6%, +30.3%, + 15.6%, and +5.1%, respectively, with no change in controls. Differences between intervention groups and controls were significant for BUA and OCSI (p < .05). TLPA and SLPA groups engaged in an average of 4.5 and 3.4 hours/week of physical activity, respectively, over the intervention period. The SLPA group continued to exercise after the intervention had ceased, whereas the TLPA group did not.
  
  
  CONCLUSIONS
  Previously inactive teenage girls can adhere to an osteogenic activity program whether supervised or directing their own activity. Longer-term, sustainable initiatives with this age group are needed and might focus on developing personal skills for physical activity.
authors.affiliation: Centre for Health Behaviour Research, Department of Health, Sport and Exercise Science, School of Health Sciences, Waterford Institute of Technology, Cork Road, Waterford, Ireland. nmurphy@wit.ie
authors.forename: Niamh M
authors.initials: NM
authors.lastname: Murphy
authors.forename: Melanie
authors.initials: M
authors.lastname: Ni Dhuinn
authors.forename: Philip A
authors.initials: PA
authors.lastname: Browne
authors.forename: Maoilíosa M
authors.initials: MM
authors.lastname: Orathaille
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000886:Anthropometry; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D002136:Calcium, Dietary / Q000008:administration & dosage; D015444:Exercise; D005260:Female; D017144:Focus Groups; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D007494:Ireland; D010809:Physical Fitness; D011795:Surveys and Questionnaires; D013663:Teaching; D014463:Ultrasonography
chemical_list: D002136:Calcium, Dietary