Maintaining physical activity among older adults: 24-month outcomes of the Keep Active Minnesota randomized controlled trial

Brian C. Martinson, Nancy E. Sherwood, A. Lauren Crain, Marcia G. Hayes, Abby C. King, Nico P. Pronk, Patrick J. O'Connor

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Objective: To evaluate the efficacy at 6-, 12-, and 24-month follow-up of Keep Active Minnesota (KAM), a telephone and mail-based intervention designed to promote physical activity (PA) . maintenance among currently active adults age 50 to 70. Method: Participants who reported having recently increased their MVPA to a minimum of 2d/wk, 30. min/bout, (. N=. 1049) were recruited in 2004 and 2005 from one large managed care organization in Minnesota, and randomly assigned to either treatment (KAM; . N=. 523), or Usual Care (UC; . N=. 526) with PA assessed using the CHAMPS questionnaire, and expressed as kcal/wk energy expenditure. Results: We find a sustained, significant benefit of the intervention at 6, 12 and 24months. kcal/wk expenditure in moderate or vigorous activities was higher at 6 (p<.03, Cohen's d6m=.16), 12 (p<.04, d12m=.13) and 24months (p<.01, d24m=.16) for KAM participants, compared to UC participants. Conclusions: The KAM telephone- and mail-based PA maintenance intervention was effective at maintaining PA in both the short-term (6. months) and longer-term (12 and 24. months) relative to usual care.

Original languageEnglish (US)
Pages (from-to)37-44
Number of pages8
JournalPreventive medicine
Issue number1
StatePublished - Jul 2010

Bibliographical note

Funding Information:
This study was supported by a grant from the National Institute on Aging ( R01 AG023410 ). The project was initiated and analyzed by the study investigators. At no point was the study sponsor involved in the study design; in the collection, analysis or interpretation of the data, in the writing of this report; or in the decision to submit the paper for publication. For her capable project management during the study startup period we thank Kirsten Hase. For their dedicated service as a Data Safety Monitoring Board, we thank Drs. Mark Pereira, Vincent Chen and Michael Levitt. And finally, we thank Karen Speicher, Jessica Clausen, Colleen Flattum, and Stephanie Williams for their invaluable contributions as telephone coaches and counselors on the study.


  • Exercise/physical activity behavioral research
  • Health maintenance organizations
  • Intervention studies
  • Randomized controlled trial


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