Joel E. Williams

Utility of pedometers for assessing physical activity: Construct validity

AbstractValid assessment of physical activity is important to researchers and practitioners interested in surveillance, screening, programme evaluation and intervention. The validity of an assessment instrument is commonly considered its most important attribute. Convergent validity is the extent to which an instrument’s output is associated with that of other instruments intended to measure the same exposure of interest. A systematic review of the literature produced 25 articles directly relevant to the question of convergent validity of pedometers against accelerometers, observation, and self-reported measures of physical activity. Reported correlations were pooled and a median r-value was computed. Pedometers correlate strongly (median r = 0.86) with different accelerometers (specifically uniaxial accelerometers) depending on the specific instruments used, monitoring frame and conditions implemented, and the manner in which the outputs are expressed. Pedometers also correlate strongly (median r = 0.82) with time in observed activity. Time in observed inactivity correlated negatively with pedometer outputs (median r = -0.44). The relationship with observed steps taken depended upon monitoring conditions and speed of walking. The highest agreement was apparent during ambulatory activity (running, walking) or during sitting (when both observation and pedometers would register few steps taken). There was consistent evidence of reduced accuracy during slow walking. Pedometers correlate moderately with different measures of energy expenditure (median r = 0.68). The relationship between pedometer outputs and energy expenditure is complicated by the use of many different direct and indirect measures of energy expenditure and population samples. Concordance with self-reported physical activity (median r = 0.33) varied depending upon the self-report instrument used, individuals assessed, and how pedometer outputs are expressed (e.g. steps, distance travelled, energy expenditure). Pedometer output has an inverse relationship with reported time spent sitting (r = -0.38). The accumulated evidence herein provides ample support that the simple and inexpensive pedometer is a valid option for assessing physical activity in research and practice.

Outcome expectations, barriers, and strategies for healthful eating: a perspective from adolescents from low-income families.

To better understand outcome expectations, barriers, and strategies for healthful eating, 5 structured focus groups were conducted with adolescents from low-income families (n = 48; 83% Black students; 10–14 years old). The focus group questions dealt with healthful eating in different settings: home, school, and other eating establishments. Results suggested that healthful eating is important to this population, but perceived barriers prevent the consistent consumption of healthful foods. Strategies suggested by participants to increase healthful eating (eg, parents and schools making healthy foods that look and taste good more available) should be considered when developing nutrition interventions for adolescents from low-income families.

Family and Community Interventions to Prevent and Control Obesity

Obesity is now a worldwide epidemic. Currently, more than 40 million children younger than 5 years are overweight and this number is projected to rise to 60 million by 2020.1 Weight status is strongly associated with the development of chronic disease, and the increased morbidity places an incredible burden on society. It is widely accepted that obesity is associated with lifestyle factors of physical activity and eating behaviors. Factors from the broader physical, social, and cultural environments, and within families, influence weight status of children.2 Many of these factors are yet to be identified, and relationships among known factors are complex and not well understood. The National Institutes of Health and the US Department of Agriculture have proposed a research agenda for social and behavioral scientists to “examine how social contexts influence health and elucidate the mechanisms through which those mechanisms operate” and to “develop ways to intervene on those factors for preventing obesity,” respectively. A critical step in developing successful interventions to increase physical activity and healthy eating involves understanding how the family and community environments influence weight-regulating behaviors, the detection of barriers and facilitators of these behaviors, and the identification of the best ways to engage families and communities for comprehensive health promotion efforts.3 The articles in this issue of Family & Community Health focus on family and community influences on weight-regulating behaviors and energy balance. These studies are grounded in health behavior theory, involve some type of intervention, and focus on underserved (eg, minority, low-income, rural, immigrant) populations. The article by Arredondo et al presents a church-based pilot study with Latina mother-daughter dyads. They used mixed methods and focused on family communication and physical activity. The article by George et al involves a school-based combined pilot study examining physical health and mental health outcomes. They also used mixed methods and explored parenting