Joel E. Williams

Bio: Joel E. Williams is an academic researcher from University of South Carolina. The author has contributed to research in topics: Behavioral Risk Factor Surveillance System & Population. The author has an hindex of 8, co-authored 11 publications receiving 1414 citations. Previous affiliations of Joel E. Williams include South Carolina Department of Health and Environmental Control.

Utility of pedometers for assessing physical activity: convergent validity.

Abstract: Valid 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.

A Preliminary Test of a Student-Centered Intervention on Increasing Physical Activity in Underserved Adolescents

Abstract: Background—Previous studies have shown that choice and self-initiated behavior change are important for increasing intrinsic motivation and physical activity (PA), however, little of this research has focused on underserved adolescents. Purpose—This study examined the effects of a 4-week student-centered intervention on increasing PA in underserved adolescents. Methods—Twenty-eight students in the intervention school were matched (on race, percentage on free or reduced-price lunch program, gender, and age) with 20 students from another school who served as the comparison group (30 girls, 18 boys; ages 10–12 years; 83% African American; 83% on free or reduced-price lunch). The student-centered intervention was consistent with selfdetermination (motivation) theory and social cognitive theory in that it emphasized increasing intrinsic motivation and behavioral skills for PA. Intervention adolescents took ownership in selecting a variety of PA activities in which to participate, and they generated coping strategies for making effective PA behavior changes. Results—Intervention participants showed greater increases in accelerometer estimates of time spent in moderate PA, moderate-to-vigorous PA, and vigorous PA from baseline to Week 4 of the intervention than the comparison group. Intervention participants also showed greater increases in PA motivation and positive self-concept for PA than comparison adolescents. Conclusions—This study provides preliminary evidence that increasing adolescent involvement and choice of activities may be important in developing future PA interventions for underserved adolescents.

Brief Report: A Qualitative Study of Gender Preferences and Motivational Factors for Physical Activity in Underserved Adolescents

Abstract: OBJECTIVE: This study used focus groups to identify preferences for physical activity (PA) and motivational themes for increasing PA in underserved adolescents. METHODS: Fifty-one adolescents, on the free lunch program (25 males and 26 females; ages 10-13 years; 72% African-American, 19% white, and 9% other minorities) participated in focus groups (6-10 children per group; same gender). The data were transcribed and coded into themes. A content analysis was performed using QSR NVivo. RESULTS: Boys rated their favorite activities as playing basketball, football, soccer, and baseball. Girls rated their favorite activities as playing basketball, swimming, and roller-skating. For motivational themes, boys and girls most frequently stated that they would participate in PA if it was a fun, provided a health benefit, and if there were a variety of choices offered. Being involved with friends was also identified as important to both boys and girls. CONCLUSIONS: The findings from this qualitative study suggest that including components of choice and a variety of physical activities may be important elements for intervention programs in underserved adolescents. Language: en

Use of complementary and alternative medicine for weight control in the United States.

Abstract: Objectives: The purpose was to assess the prevalence and correlates of complementary and alternative medicine use for weight control. Design: A list-assisted random-digit-dialed telephone survey of...

Expert Committee Recommendations Regarding the Prevention, Assessment, and Treatment of Child and Adolescent Overweight and Obesity: Summary Report

Abstract: To revise 1998 recommendations on childhood obesity, an Expert Committee, comprised of representatives from 15 professional organizations, appointed experienced scientists and clinicians to 3 writing groups to review the literature and recommend approaches to prevention, assessment, and treatment. Because effective strategies remain poorly defined, the writing groups used both available evidence and expert opinion to develop the recommendations. Primary care providers should universally assess children for obesity risk to improve early identification of elevated BMI, medical risks, and unhealthy eating and physical activity habits. Providers can provide obesity prevention messages for most children and suggest weight control interventions for those with excess weight. The writing groups also recommend changing office systems so that they support efforts to address the problem. BMI should be calculated and plotted at least annually, and the classification should be integrated with other information such as growth pattern, familial obesity, and medical risks to assess the child’s obesity risk. For prevention, the recommendations include both specific eating and physical activity behaviors, which are likely to promote maintenance of healthy weight, but also the use of patient-centered counseling techniques such as motivational interviewing, which helps families identify their own motivation for making change. For assessment, the recommendations include methods to screen for current medical conditions and for future risks, and methods to assess diet and physical activity behaviors. For treatment, the recommendations propose 4 stages of obesity care; the first is brief counseling that can be delivered in a health care office, and subsequent stages require more time and resources. The appropriateness of higher stages is influenced by a patient’s age and degree of excess weight. These recommendations recognize the importance of social and environmental change to reduce the obesity epidemic but also identify ways healthcare providers and health care systems can be part of broader efforts.

How many steps/day are enough? Preliminary pedometer indices for public health.

Abstract: readily being used by researchers and practitioners to assess and motivate physical activity behaviours. Pedometer-determined physical activity indices are needed to guide their efforts. Therefore, the purpose of this article is to review the rationale and evidence for general pedometer-based indices for research and practice purposes. Specifically, we evaluate popular recommendations for steps/day and attempt to translate existing physical activity guidelines into steps/day equivalents. Also, we appraise the fragmented evidence currently available from associations derived from cross-sectional studies and a limited number of interventions that have documented improvements (primarily in body composition and/or blood pressure) with increased steps/day. A value of 10 000 steps/day is gaining popularity with the media and in practice and can be traced to Japanese walking clubs and a business slogan 30+ years ago. 10 000 steps/day appears to be a reasonable estimate of daily activity for apparently healthy adults and studies are emerging documenting the health benefits of attaining similar levels. Preliminary evidence suggests that a goal of 10 000 steps/day may not be sustainable for some groups, including older adults and those living with chronic diseases. Another concern about using 10 000 steps/ day as a universal step goal is that it is probably too low for children, an important target population in the war against obesity. Other approaches to pedometer-determined physical activity recommendations that are showing promise of health benefit and individual sustainability have been based on incremental improvements relative to baseline values. Based on currently available evidence, we propose the following preliminary indices be used to classify pedometer-determined physical activity in healthy adults: (i) 12 500 steps/day are likely to be classified as ‘highly active’.

Effect of physical activity on cognitive function in older adults at risk for Alzheimer disease: a randomized trial.

Abstract: Context Many observational studies have shown that physical activity reduces the risk of cognitive decline; however, evidence from randomized trials is lacking. Objective To determine whether physical activity reduces the rate of cognitive decline among older adults at risk. Design and Setting Randomized controlled trial of a 24-week physical activity intervention conducted between 2004 and 2007 in metropolitan Perth, Western Australia. Assessors of cognitive function were blinded to group membership. Participants We recruited volunteers who reported memory problems but did not meet criteria for dementia. Three hundred eleven individuals aged 50 years or older were screened for eligibility, 89 were not eligible, and 52 refused to participate. A total of 170 participants were randomized and 138 participants completed the 18-month assessment. Intervention Participants were randomly allocated to an education and usual care group or to a 24-week home-based program of physical activity. Main Outcome Measure Change in Alzheimer Disease Assessment Scale–Cognitive Subscale (ADAS-Cog) scores (possible range, 0-70) over 18 months. Results In an intent-to-treat analysis, participants in the intervention group improved 0.26 points (95% confidence interval, −0.89 to 0.54) and those in the usual care group deteriorated 1.04 points (95% confidence interval, 0.32 to 1.82) on the ADAS-Cog at the end of the intervention. The absolute difference of the outcome measure between the intervention and control groups was −1.3 points (95% confidence interval,−2.38 to −0.22) at the end of the intervention. At 18 months, participants in the intervention group improved 0.73 points (95% confidence interval, −1.27 to 0.03) on the ADAS-Cog, and those in the usual care group improved 0.04 points (95% confidence interval, −0.46 to 0.88). Word list delayed recall and Clinical Dementia Rating sum of boxes improved modestly as well, whereas word list total immediate recall, digit symbol coding, verbal fluency, Beck depression score, and Medical Outcomes 36-Item Short-Form physical and mental component summaries did not change significantly. Conclusions In this study of adults with subjective memory impairment, a 6-month program of physical activity provided a modest improvement in cognition over an 18-month follow-up period. Trial Registration anzctr.org.au Identifier: ACTRN12605000136606