467 Journal of Physical Activity and Health, 2009, 6, 467-474 © 2009 Human Kinetics, Inc. Background: Although many Japanese older adults spend more than an hour each day walk- ing for exercise, the intensity is often lower than the minimum level associated with vari- ous health benefits. The purpose of this study was to evaluate the efficacy of a lifestyle phys- ical activity intervention on improving quan- tity and quality of daily physical activity (DPA) as well as cardiorespiratory endurance in com- munity-dwelling older women. Methods: 68 women (60–78 yr of age) were randomly assigned to either a lifestyle physical activity intervention group (LIFE) or control group. During the 12-wk intervention, feedback based on accelerometer DPA data (number of daily steps (STEPS) and time spent performing daily moderate intensity physical activity (MPA) was provided to each participant in LIFE every two weeks. Cardiorespiratory endurance was evaluated using the 12-Minute Walk Test (12- MW). Results: Following the 12-wk interven- tion, significant group interactions were observed for STEPS, MPA, and cardiorespira- tory endurance. LIFE increased STEPS by 16%, MPA by 53%, and the distance walked during the 12-MW by 10%. Conclusions: Pro- motion of DPA using accelerometers can sig- nificantly improve quantity and quality of daily physical activity as well as cardiorespiratory endurance in older women. Keywords: elderly, data feedback, moderate intensity, walking Koizumi, Islam, and Takeshima are with the Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan. NL Rogers is with the School of Community Affairs Gerontol- ogy Program, Wichita State University, Wichita, KS, USA. ME Rogers is with the Center for Physical Activity and Aging, Dept of Human Performance Studies, Wichita State Univer- sity, Wichita, KS, USA. Kusunoki is with the School of Biology-Oriented Technology, Kinki University, Kinokawa, Japan. Efficacy of an Accelerometer-Guided Physical Activity Intervention in Community-Dwelling Older Women Daisuke Koizumi, Nicole L. Rogers, Michael E. Rogers, Mohammod M. Islam, Masanobu Kusunoki, and Nobuo Takeshima Physical inactivity is a leading public health prob- lem associated with decreased longevity as well as car- diovascular disease, cancer, obesity, diabetes, and other diseases. 9,27 It has been demonstrated that regular exer- cise plays an important role in maintaining and promot- ing health, physical fitness, and functional independence in older adults. 1 Many intervention programs have been implemented to enhance physical activity among older adults 28 and improved health status and functional per- formance have been noted in these studies. 30 However, despite the demonstrated benefits of implemented inter- ventions, the number of older adults participating in regular exercises is still very low. 27 Recently, older adult physical activity program- ming has focused on promoting daily physical activity 4 (DPA). This approach provides opportunities and options to increase physical activity for individuals while attempting to take into consideration lifestyle preference and is targeted toward individuals who are inactive or inadequately active. Adequate lifestyle phys- ical activity is defined 6 as the daily accumulation of at least 30 minutes of self-selected activities, which includes all planned and unplanned leisure, occupa- tional, household, and other daily activities that are at least moderate to vigorous in their intensity. To fulfill the prescribed amount of DPA in adequate intensities, a unique method of measuring quantity as well as the intensity of DPA is needed. Quantification of DPA in older adults is an area of interest for many public health professionals. Several methods of quantifying physical activity and energy expenditure are available. 18 Many of these methods are limited in accuracy and/or feasibility for estimating physical activity or energy expenditure in particular populations or circumstances. 18 Recently, accelerometers have become increasingly popular for assessing the intensity of physical activity in communi- ty-dwelling older adults. 7 Many studies have docu- mented the validity of accelerometry-based activity monitors under both laboratory and field con- ditions. 7,8,29 Various interventions such as mass and print media have been effectively used to motivate people to increase DPA. 15 Direct contact interventions such as telephone