Reliability of RT3 accelerometers among overweight and obese adults

Gerald J. Jerome, Deborah Rohm Young, D. A.N. Laferriere, Chuhe Chen, William M. Vollmer

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


Purpose: Accurate and reliable measurement of physical activity plays an important role in assessing effective lifestyle interventions for obesity. This study examined reliability of accelerometer-based estimates of physical activity levels of overweight and obese adults before and after a lifestyle weight loss program. Methods: Participants were overweight and obese (body mass index = 25-45 kgm -2) members (n = 1592; 67% female, 42% African American) of the multicenter weight loss maintenance trial. They wore RT3 accelerometers during waking hours for 7 d at baseline and after a 6-month weight loss intervention that included diet and physical activity recommendations. Moderate-to-vigorous physical activity (MVPA) and MVPA occurring in bouts >10 min (bout MVPA) were assessed. Results: At baseline, wear time minimums of 10 and 6 hd -1 resulted in similar average minutes per day of MVPA (18.3 and 18.0 min) and MVPA bout minutes per day (6.9 and 6.7 min). Similar wear times occurred after the weight loss intervention for MVPA (27.0 and 26.8 min) and bout MVPA (15.1 and 15.0 min). Reliability measurements by intraclass correlation (ICC) were larger for 4 versus 2 d-wk -1 minimum wear time for both MVPA and bout MVPA (4-d ICC = 0.27-0.44 and 2-d ICC = 0.19-0.38), but there was little increase in ICC comparing 4 (ICC = 0.27-0.44) and 7 dwk -1 (ICC = 0.30-0.46). Conclusions: Longer wear time requirements did not result in significant increases in reliability. Using 4 d of data with >6 hd -1 of wear time optimized the balance between ICC and participant burden in overweight and obese adults before and after a weight loss intervention. Future investigations using accelerometers to estimate MVPA in overweight and and obesa samples can consider requiring less monitor wear time.

Original languageEnglish (US)
Pages (from-to)110-114
Number of pages5
JournalMedicine and Science in Sports and Exercise
Issue number1
StatePublished - Jan 2009
Externally publishedYes


  • Ambulatory monitoring
  • Bouts
  • Exercise
  • Measurement
  • Physical activity

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


Dive into the research topics of 'Reliability of RT3 accelerometers among overweight and obese adults'. Together they form a unique fingerprint.

Cite this