Detecting bouts of physical activity in a field setting

Quantifying Physical Activity and Sedentary Behavior in Adults with Intellectual Disability: A Scoping Review of Assessment Methodologies

Background/Objectives: Methodologies for assessing behavior form the foundation of health promotion and disease prevention. Physical activity (PA) and sedentary behavior (SB) assessment methodologies have predominantly been developed for adults without an intellectual disability (ID), raising credibility concerns for adults with ID. The purpose was to synthesize the current state of assessment methodologies for quantifying PA and SB volume in the free-living setting for adults with an ID. Methods: Following PRISMA guidelines, eleven databases were searched through December 2023, yielding 8174 records. Data were extracted in Covidence (v.2.0), obtaining quantified PA and SB volume and assessment methodology characteristics across data collection and analysis, including tool(s) and technique(s) used, preparatory actions taken, instructions provided, and behavioral strategies employed during data collection. Results: Of the 8174 articles screened, 91 met the inclusion criteria. Common metrics included minutes/hours per day/week and steps per day/week. Despite 80% of the studies using objective techniques, substantial variation existed across studies regarding wearable models, sampling frequency and epoch length settings, calibration protocols, wearable placements, and data processing techniques. Limited studies provided instructions that did not exclusively rely on spoken language. Behavioral strategies varied, including self-monitoring, providing assistance or supervision, administering questionnaires verbally, issuing reminders, and offering monetary incentives. Conclusions: This review underscores the need for greater consistency and accessibility in PA and SB assessment methodology for adults with ID. Tailored preparation, instruction, and behavioral strategies may enhance assessment viability and suitability for adults with ID, with or without caregiver or researcher involvement in the free-living setting.

Randomized trial examining the effect of exercise and wellness interventions on preventing postpartum depression and perceived stress

BACKGROUND

Approximately 13-19% of postpartum women experience postpartum depression and a majority report at least some stress during the postpartum phase. Traditional interventions such as psychotherapy and antidepressant medications are often not feasible or desirable. The purpose of this study was to examine two low cost, brief, accessible interventions designed to prevent postpartum depression and perceived stress among women at high risk.

METHODS

Participants (n = 450) who were on average four weeks postpartum, had a history of depression before pregnancy, and exercised less than 60 min per week were randomly assigned to one of the following three conditions: (1) 6-month telephone-based exercise intervention; (2) 6-month telephone-based wellness/support intervention (e.g., healthy eating, sleep, and perceived stress); or (3) usual care.

RESULTS

Overall, 2.4% of participants met criteria for depression at 6 months and 3.6% at 9 months with no differences between groups. At 6 months following randomization, median symptoms of depression were significantly lower among wellness participants compared to usual care participants (b = - 1.00, SE = 0.46, p = .03). Perceived stress at 6 months post-randomization was significantly lower among exercise vs. usual care participants (b = - 2.00, SE = .98, p = .04) and exercise vs. wellness participants (b = - 2.20, SE = 1.11, p = .04).

CONCLUSIONS

The wellness intervention was efficacious for preventing symptoms of depression; however, postpartum depression that met the diagnostic criteria was surprisingly low in all conditions among this at risk sample of postpartum women. Exercise interventions may have a protective effect on perceived stress among women at risk for postpartum depression. Practitioners should consider integrating exercise and wellness interventions into postpartum care.

TRIAL REGISTRATION

Clinical Trials Number: NCT01883479 (06/21/2013).

Program to improve mobility in aging (PRIMA) study: Methods and rationale of a task-oriented motor learning exercise program

Walking difficulty is a common and costly problem in older adults. A potentially important yet unaddressed strategy to enhance walking ability through exercise intervention is to add a timing and coordination component in gait training (i.e. task specific timing and coordination exercise intervention) to the usual strength, endurance, and flexibility training. We describe the methods and rationale of a randomized single-blind, physical therapist supervised, exercise intervention trial to compare the effects of a standard strength, endurance, and flexibility program to a standard plus timing and coordination program in community-dwelling older adults walking slower than the desired gait speed of 1.2 m/s. Exercise sessions are twice weekly for 12 weeks. Participants are assessed at baseline, 12 weeks (post intervention), 24 weeks and 36 weeks. The primary outcome is gait speed, secondary outcomes represent components of the interventions (strength, endurance, flexibility, timing and coordination), and tertiary outcomes are measure of activity and participation (Late Life Function and Disability Instrument and physical activity). The findings of this trial will (1) establish if a standard-plus task specific timing and coordination program is superior to a standard strength and endurance program in improving mobility, activity and participation and (2) determine if the improvements are sustained over time. The information derived from this project will provide valuable insight into the prevention and management of walking difficulty, which is so common in older Americans.

Rationale, design, and baseline data for the Healthy Mom II Trial: A randomized trial examining the efficacy of exercise and wellness interventions for the prevention of postpartum depression

Approximately 13-19% of women experience postpartum depression and approximately one-third of women who have a history of depression develop depression during the postpartum phase. Exercise is an efficacious intervention for depression among adults; however, few studies have examined the effect of exercise on postpartum depression. The purpose of this study was to conduct a randomized controlled trial examining the effect of exercise and wellness interventions on preventing postpartum depression among women at risk. Specifically, women (n = 450) who were on average 4.35 weeks postpartum and had a history of depression were randomly assigned to one of the following three conditions: (1) Telephone-based exercise intervention; (2) telephone-based wellness/support intervention (covered topics such as sleep, stress, and healthy eating); or (3) usual care. Both interventions lasted six months. The exercise intervention was based on social cognitive theory and the Transtheoretical model and was specifically designed to motivate postpartum women to exercise. The primary dependent variable was depression based on the Structured Clinical Diagnostic Interview (SCID). Secondary dependent variables included the Edinburgh Postnatal Depression Scale, PHQ-9, and Perceived Stress Scale. Potential mediator variables included quality of sleep, postpartum social support, fatigue, and exercise attitudes. Questionnaires were administered at baseline, six, and nine months. The purpose of this paper is to summarize the methodology, study design, and baseline data for this study. This trial will provide important information regarding the efficacy of exercise and wellness interventions for preventing postpartum depression.

Examination of a telephone-based exercise intervention for the prevention of postpartum depression: design, methodology, and baseline data from The Healthy Mom study

Research indicates that exercise is an efficacious intervention for depression among adults; however, little is known regarding its efficacy for preventing postpartum depression. The Healthy Mom study was a randomized controlled trial examining the efficacy of an exercise intervention for the prevention of postpartum depression. Specifically, postpartum women with a history of depression or a maternal family history of depression (n=130) were randomly assigned to a telephone-based exercise intervention or a wellness/support contact control condition each lasting six months. The exercise intervention was designed to motivate postpartum women to exercise based on Social Cognitive Theory and the Transtheoretical Model. The primary dependent variable was depression based on the Structured Clinical Diagnostic Interview (SCID). Secondary dependent variables included scores on the Edinburgh Postnatal Depression Scale, the PHQ-9, and the Perceived Stress Scale. The purpose of this paper is to describe the study design, methodology, and baseline data for this trial. Upon completion of the trial, the results will yield important information about the efficacy of exercise in preventing postpartum depression.

Validity of activity monitors in health and chronic disease: a systematic review

The assessment of physical activity in healthy populations and in those with chronic diseases is challenging. The aim of this systematic review was to identify whether available activity monitors (AM) have been appropriately validated for use in assessing physical activity in these groups. Following a systematic literature search we found 134 papers meeting the inclusion criteria; 40 conducted in a field setting (validation against doubly labelled water), 86 in a laboratory setting (validation against a metabolic cart, metabolic chamber) and 8 in a field and laboratory setting. Correlation coefficients between AM outcomes and energy expenditure (EE) by the criterion method (doubly labelled water and metabolic cart/chamber) and percentage mean differences between EE estimation from the monitor and EE measurement by the criterion method were extracted. Random-effects meta-analyses were performed to pool the results across studies where possible. Types of devices were compared using meta-regression analyses. Most validation studies had been performed in healthy adults (n = 118), with few carried out in patients with chronic diseases (n = 16). For total EE, correlation coefficients were statistically significantly lower in uniaxial compared to multisensor devices. For active EE, correlations were slightly but not significantly lower in uniaxial compared to triaxial and multisensor devices. Uniaxial devices tended to underestimate TEE (−12.07 (95%CI; -18.28 to −5.85) %) compared to triaxial (−6.85 (95%CI; -18.20 to 4.49) %, p = 0.37) and were statistically significantly less accurate than multisensor devices (−3.64 (95%CI; -8.97 to 1.70) %, p<0.001). TEE was underestimated during slow walking speeds in 69% of the lab validation studies compared to 37%, 30% and 37% of the studies during intermediate, fast walking speed and running, respectively. The high level of heterogeneity in the validation studies is only partly explained by the type of activity monitor and the activity monitor outcome. Triaxial and multisensor devices tend to be more valid monitors. Since activity monitors are less accurate at slow walking speeds and information about validated activity monitors in chronic disease populations is lacking, proper validation studies in these populations are needed prior to their inclusion in clinical trials.

Research to Encourage Exercise for Fibromyalgia (REEF): use of motivational interviewing design and method

Fibromyalgia (FM), defined as the presence of both chronic widespread pain and the finding of 11/18 tender points on examination, is an illness associated with major personal and societal burden. Supervised aerobic exercise is an important treatment modality to improve patient symptoms. Unfortunately, adherence to an exercise regimen after a structured supervised program is disappointingly low. Since FM is a chronic illness, studies are needed to test strategies that would enhance exercise adherence in these individuals. Individuals who are able to adhere to exercise almost always maintain the symptomatic benefits of exercise. The objective of this paper was to describe the protocol of the Research to Encourage Exercise for Fibromyalgia (REEF). REEF is a randomized attention-controlled trial that seeks to test the efficacy of 6 sessions of telephone delivered motivational interviewing (MI) that targets exercise adherence to improve FM-relevant clinical outcomes (i.e., physical function and pain severity). The trial has recently completed enrolling 216 subjects, and randomization has resulted in well-balanced groups. Details on the study design, MI program, and treatment fidelity are provided in the paper. Outcome assessments at week 12, week 24 and week 36 will test the immediate, intermediate and long-term effects of exercise-based MI on adherence (as measured by the Community Health Activities Model Program for Seniors/CHAMPS and accelerometer) and clinical outcomes. When completed, REEF will determine whether exercise-based MI could be utilized as a management strategy to sustain the clinical benefits of exercise for FM.

Accelerometer use in a physical activity intervention trial

This paper describes the application of best practice recommendations for using accelerometers in a physical activity (PA) intervention trial, and the concordance of different methods for measuring PA. A subsample (n = 63; 26%) of the 239 healthy, sedentary adults participating in a PA trial (mean age = 47.5; 82% women) wore the ActiGraph monitor at all 3 assessment time points. ActiGraph data were compared with self-report (i.e., PA weekly recall and monthly log) and fitness variables. Correlations between the PA recall and ActiGraph for moderate intensity activity ranged from 0.16-0.48 and from 0.28-0.42 for vigorous intensity activity. ActiGraph and fitness [estimated VO(2)(ml/kg/min)] had correlations of 0.15-0.45. The ActiGraph and weekly self-report were significantly correlated at all time points (correlations ranged from 0.23 to 0.44). In terms of detecting intervention effects, intervention groups recorded more minutes of at least moderate-intensity PA on the ActiGraph than the control group at 6 months (min = 46.47, 95% CI = 14.36-78.58), but not at 12 months. Limitations of the study include a small sample size and only 3 days of ActiGraph monitoring. To obtain optimal results with accelerometers in clinical trials, the authors recommend following best practice recommendations: detailed protocols for monitor use, calibration of monitors and validation of data quality, and use of validated equations for analysis. The ActiGraph has modest concordance with other assessment tools and is sensitive to change over time. However, until more information validating the use of accelerometry in clinical trials becomes available, properly administered self-report measures of PA should remain part of the assessment battery.

A comparison of direct versus self-report measures for assessing physical activity in adults: a systematic review

BACKGROUND

Accurate assessment is required to assess current and changing physical activity levels, and to evaluate the effectiveness of interventions designed to increase activity levels. This study systematically reviewed the literature to determine the extent of agreement between subjectively (self-report e.g. questionnaire, diary) and objectively (directly measured; e.g. accelerometry, doubly labeled water) assessed physical activity in adults.

METHODS

Eight electronic databases were searched to identify observational and experimental studies of adult populations. Searching identified 4,463 potential articles. Initial screening found that 293 examined the relationship between self-reported and directly measured physical activity and met the eligibility criteria. Data abstraction was completed for 187 articles, which described comparable data and/or comparisons, while 76 articles lacked comparable data or comparisons, and a further 30 did not meet the review's eligibility requirements. A risk of bias assessment was conducted for all articles from which data was abstracted.

RESULTS

Correlations between self-report and direct measures were generally low-to-moderate and ranged from -0.71 to 0.96. No clear pattern emerged for the mean differences between self-report and direct measures of physical activity. Trends differed by measure of physical activity employed, level of physical activity measured, and the gender of participants. Results of the risk of bias assessment indicated that 38% of the studies had lower quality scores.

CONCLUSION

The findings suggest that the measurement method may have a significant impact on the observed levels of physical activity. Self-report measures of physical activity were both higher and lower than directly measured levels of physical activity, which poses a problem for both reliance on self-report measures and for attempts to correct for self-report - direct measure differences. This review reveals the need for valid, accurate and reliable measures of physical activity in evaluating current and changing physical activity levels, physical activity interventions, and the relationships between physical activity and health outcomes.

A review of physical activity measures used among US Latinos: guidelines for developing culturally appropriate measures

BACKGROUND

As the US population continues to grow and diversify, there is a need for progressive physical activity measurement and cross-cultural research. Studies suggest that US Latinos are among the most sedentary of ethnic groups compared to others; however, study findings may be biased given that some measures may not be culturally sensitive for assessing behaviors that are not characterized as leisure time physical activity.

PURPOSE

The primary objective of this review was to identify and evaluate measures used to quantify physical activity among US Latinos.

METHODS

A review of the literature was performed and studies examining levels of physical activity among Spanish and English speaking Latinos were documented. This process involved identifying existing guidelines for the purpose of culturally adapting and/or translating (into Spanish) physical activity measures for the Latino population. These guidelines were used as the minimal criteria for the evaluation of the 13 identified measures of physical activity.

RESULTS

Of these 13 measures, four were available in English and nine were available in Spanish. One English measure met the guidelines for being culturally adapted for assessing physical activity among Latinos. There were no Spanish measures that met all the guidelines for physical activity assessment among Spanish-speaking Latinos. Lastly, the identified guidelines for developing culturally appropriate measures were improved to advance physical activity measurement among ethnic and cultural groups.

CONCLUSION

Future research should merit the use of culturally appropriate guidelines to increase the understanding of physical activity patterns in the USA.

Gait speed and step-count monitor accuracy in community-dwelling older adults

Accurate assessment of physical activity (PA) is necessary to identify the sedentary older individual who is in need of activity intervention. Activity monitors are quite popular, although it has been suggested that they are less accurate at slow gait speeds.

PURPOSE

To examine the accuracy of the three activity monitors in older individuals who walk at various gait speeds.

METHODS

Participants were 34 community-dwelling older men and women (mean age 79.2) who were asked to simultaneously wear three activity monitors: the Yamax DigiWalker (DW) pedometer (hip), the Actigraph (AG) accelerometer (hip), and the StepWatch activity monitor (SAM) (ankle). Monitor accuracy was evaluated against observed steps taken during a 100-step walking test. Percent error of the monitors was calculated as [(monitor steps - observed steps)/observed steps] x 100. Participants were categorized into three groups (< 0.80, 0.80-1.0, > 1.0 m x s(-1)) according to gait speed, which was determined by a timed 4-m walk.

RESULTS

Overall, the DW and AG failed to detect 16% and 7% of observed steps, respectively, and the SAM overestimated by 5.5%. When stratified by gait speed, all three monitors faired well at the gait speeds > 1.0 m x s(-1). For gait speeds between 0.80 and 1.0 m x s(-1), the SAM overestimated steps by 6.6%, and the AG and DW underestimated steps by 5.7% and 12.7%, respectively. However, at gait speeds < 0.80 m x s(-1), the AG and DW performed poorly, underestimating steps by 19.1% and 31.2%, whereas the SAM performed better, having overestimated steps by 6.5%.

CONCLUSIONS

All three objective activity monitors performed well at moderate and higher walking speeds, but at decreased gait speeds, the SAM seemed to be the most accurate.

Accelerometers and pedometers: methodology and clinical application

PURPOSE OF REVIEW

The relationship between physical activity and health varies considerably, partly due to the difficulty of assessing physical activity accurately. This review examines recent literature on the validation of movement sensors to assess habitual physical activity. Recommendations are given for the use of movement sensors during free-living conditions and methods of data analysis and interpretation are discussed.

RECENT FINDINGS

Recent progress in physical-activity research includes detailed comparative studies of different monitor brands. The move away from using linear-regression equations and the use of novel data-analysis strategies is increasing the accuracy with which energy expenditure can be estimated from accelerometry. New technologies, including the combination of accelerometry with the measurement of physiological parameters, have great potential for the increased accuracy of physical-activity assessment.

SUMMARY

Accelerometry is able to adequately assess physical activity and its association with health outcomes but currently methods have limited accuracy for the estimation of free-living energy expenditure. Pedometers provide an inexpensive overall measure of physical activity but are unable to assess intensity, frequency and duration of activity or to estimate energy expenditure. Interpretation of monitor output is best kept as close to the measurement domain as possible.

Treatment options for type 2 diabetes in adolescents and youth: a study of the comparative efficacy of metformin alone or in combination with rosiglitazone or lifestyle intervention in adolescents with type 2 diabetes

Despite the increased prevalence of type 2 diabetes mellitus (T2DM) in the pediatric population, there is limited information about the relative effectiveness of treatment approaches. This article describes the rationale and design of a National Institutes of Health-sponsored multi-site, randomized, parallel group clinical trial designed to test the hypothesis that aggressive reduction in insulin resistance early in the course of T2DM is beneficial for prolongation of glycemic control, as well as improvement in associated abnormalities and risk factors. Specifically, the trial compares treatment with metformin with two alternate approaches, one pharmacologic (combining metformin treatment with rosiglitazone) and one combining metformin with an intensive lifestyle intervention program. The Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study recruits 800 patients over a 4-yr period and follows them for a minimum of 2 yr and maximum of 6 yr. Patients are 10-17 yr of age, within 2 yr of diagnosis of diabetes at the time of randomization, lack evidence of autoimmunity, and have sustained C-peptide secretion. The primary outcome is time to loss of glycemic control, defined as a hemoglobin A1c >8% for 6 consecutive months. Secondary outcomes include the effect of the alternative treatments on insulin secretion and resistance, body composition, nutrition, physical activity and fitness, cardiovascular risk monitoring, microvascular complications, quality of life, depression, eating pathology, and resource utilization. TODAY is the first large-scale, systematic study of treatment effectiveness for T2DM in youth. When successfully completed, this study will provide critical new information regarding the natural history of T2DM in youth, the benefits of initiating early aggressive treatment in these patients, and the efficacy of delivering an intensive and sustained lifestyle intervention to children with T2DM.

Step into Motion: a randomized trial examining the relative efficacy of Internet vs. print-based physical activity interventions

Over two-thirds of Americans access the Internet and therefore, the Internet may be an important channel for reaching the large population of sedentary individuals. The purpose of this paper is to describe the methods for a randomized controlled trial examining the efficacy of an Internet-based physical activity intervention relative to a print intervention that has been shown to be effective in previous trials. Specifically, 249 sedentary participants were randomized to receive one of three interventions: 1) Internet-based motivationally-tailored individualized feedback (Tailored Internet); 2) print-based motivationally-tailored individualized feedback (Tailored Print); or 3) physical activity websites currently available to the public (Standard Internet). Participants completed the 7-Day Physical Activity Recall interview, wore an objective physical activity monitor (i.e., ActiGraph), and participated in a treadmill fitness test at baseline, 6, and 12 months. The sample consisted of mostly women (84.2%) and Caucasian individuals (76.4%) who reported exercising an average of 21 min per week at baseline. This is the first study that we are aware of, that has examined the efficacy of a tailored Internet-based physical activity intervention. This study will have implications for the dissemination of Internet-based physical activity interventions.

Treatment options for type 2 diabetes in adolescents and youth: a study of the comparative efficacy of metformin alone or in combination with rosiglitazone or lifestyle intervention in adolescents with type 2 diabetes

Despite the increased prevalence of type 2 diabetes mellitus (T2DM) in the pediatric population, there is limited information about the relative effectiveness of treatment approaches. This article describes the rationale and design of a National Institutes of Health-sponsored multi-site, randomized, parallel group clinical trial designed to test the hypothesis that aggressive reduction in insulin resistance early in the course of T2DM is beneficial for prolongation of glycemic control, as well as improvement in associated abnormalities and risk factors. Specifically, the trial compares treatment with metformin with two alternate approaches, one pharmacologic (combining metformin treatment with rosiglitazone) and one combining metformin with an intensive lifestyle intervention program. The Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study recruits 800 patients over a 4-yr period and follows them for a minimum of 2 yr and maximum of 6 yr. Patients are 10-17 yr of age, within 2 yr of diagnosis of diabetes at the time of randomization, lack evidence of autoimmunity, and have sustained C-peptide secretion. The primary outcome is time to loss of glycemic control, defined as a hemoglobin A1c >8% for 6 consecutive months. Secondary outcomes include the effect of the alternative treatments on insulin secretion and resistance, body composition, nutrition, physical activity and fitness, cardiovascular risk monitoring, microvascular complications, quality of life, depression, eating pathology, and resource utilization. TODAY is the first large-scale, systematic study of treatment effectiveness for T2DM in youth. When successfully completed, this study will provide critical new information regarding the natural history of T2DM in youth, the benefits of initiating early aggressive treatment in these patients, and the efficacy of delivering an intensive and sustained lifestyle intervention to children with T2DM.

Examination of print and telephone channels for physical activity promotion: Rationale, design, and baseline data from Project STRIDE

BACKGROUND

Project STRIDE is a 4-year randomized controlled trial comparing two computer-based expert system guided intervention delivery channels (phone vs. print) for physical activity adoption and short-term maintenance among previously sedentary adults.

METHODS

Sedentary adults (n=239) were randomized to one of the following (1) telephone-based, individualized motivationally-tailored feedback; (2) print-based, individualized motivationally-tailored feedback; (3) contact-control delayed treatment group (received intervention after 12 months as control). This paper: (1) outlines the study design, rationale, and participant sample; and (2) describes relationships between baseline variables to better understand their influence on the efficacy of the intervention.

RESULTS

Participants averaged 19.8+/-25.0 min of physical activity/week that was at least of moderate intensity, with no group differences. The average estimated VO(2) at 85% of maximum heart rate was 25.6 ml/kg/min. Body fat was 34.1% for women and 23.2% for men and the BMI of the sample averaged 28.5 kg/m(2).

CONCLUSIONS

Project STRIDE examines non face-to-face approaches for promoting physical activity behavior. It has unique features including a direct comparison of an expert system guided intervention delivered via phone or print. Future analyses will examine the cost-effectiveness of the interventions and this will likely yield important information for policy-makers.

Conducting Accelerometer-Based Activity Assessments in Field-Based Research

PURPOSE

The purpose of this review is to address important methodological issues related to conducting accelerometer-based assessments of physical activity in free-living individuals.

METHODS

We review the extant scientific literature for empirical information related to the following issues: product selection, number of accelerometers needed, placement of accelerometers, epoch length, and days of monitoring required to estimate habitual physical activity. We also discuss the various options related to distributing and collecting monitors and strategies to enhance compliance with the monitoring protocol.

RESULTS

No definitive evidence exists currently to indicate that one make and model of accelerometer is more valid and reliable than another. Selection of accelerometer therefore remains primarily an issue of practicality, technical support, and comparability with other studies. Studies employing multiple accelerometers to estimate energy expenditure report only marginal improvements in explanatory power. Accelerometers are best placed on hip or the lower back. Although the issue of epoch length has not been studied in adults, the use of count cut points based on 1-min time intervals maybe inappropriate in children and may result in underestimation of physical activity. Among adults, 3-5 d of monitoring is required to reliably estimate habitual physical activity. Among children and adolescents, the number of monitoring days required ranges from 4 to 9 d, making it difficult to draw a definitive conclusion for this population. Face-to-face distribution and collection of accelerometers is probably the best option in field-based research, but delivery and return by express carrier or registered mail is a viable option.

CONCLUSION

Accelerometer-based activity assessments requires careful planning and the use of appropriate strategies to increase compliance.

Health and physical activity research as represented in RQES

In the past 75 years, articles in Research Quarterly for Exercise and Sport (RQES) have contributed to the understanding of the role physical activity plays in the health of individuals and populations. Articles have described laboratory and community research studies in humans and animals, presented reviews of topics and conference proceedings, and presented forums for discussion about current topics in physical activity and health. The articles reflect the growth of the profession from basic inquiry, about physiological responses to exercise (and the development of physical fitness methods and standards), to studies of the effects of exercise on physical fitness and health in various population subgroups. This evolution in RQES reflects the well recognized paradigm shift toward public health concerns for physical activity and health outcomes.

Promoting physical activity among sedentary women using pedometers

Sedentary women (n = 92) classified as low (L), medium (M), and high (H) in baseline step counts and assigned to 10,000-step goal (TSG) and personal step goal (PSG) groups (within levels) were compared on goal attainment and step counts. A significant interaction for goal attainment, F(2, 86) = 4.51, p = .014, indicated that the L group was significantly less likely to meet the TSG than the M and H groups. Step counts increased after goal assignment, but not more for one group than the other. Results of this research support the previous finding that women with low baseline step counts are unlikely to meet a TSG, but a TSG does not result in lower step counts than a PSG.

Accumulating 10,000 steps: does this meet current physical activity guidelines?

The purpose of this study was to determine whether taking 10,000 steps in a day is equivalent to meeting the current minimum physical activity guidelines of accumulating at least 30 min of moderate physical activity (IMPA). Fifty-nine women ages 20-65 years wore a pedometer and accelerometer concurrently on their right hip for 1 day. There were no differences in the age, body mass index, or the amount of time the pedometers and accelerometers were worn between the 10K+ and the < 10K groups. The 10K+ group accumulated significantly more steps and minutes of MPA than the < 10K group (M = 13,084 steps, SD = 2,603 vs. M = 7,518 steps, SD = 1,956; and M = 62.1 min, SD = 27.7 vs. M = 38.8 min, SD = 18.9; p < .05). A 2 x 2 chi-square analysis demonstrated no difference between the proportions of 10K and < 10K participants who met the step goal, when all minutes of MPA accumulated throughout the day were considered (chi2 = 1.8, df = 1, p = .175). When only continuous bouts of MPA lasting > 5 min and > 10 min were considered, a significantly greater proportion of 10K participants met the current physical activity guidelines than the < 10K participants (chi2 = 11.5, df = 1, p = .001, and chi2 = 5.9, df = 1, p = .015, respectively). Our finding, suggest that individuals who accumulate 10,000 steps/day are more likely to meet the current physical activity guidelines by engaging in the length of bouts promoted by the Centers for Disease Control and Prevention and the American College of Sports Medicine (Pate et al., 1995) and the US Surgeon General (U.S. Department of Health and Human Services, 1996). However, the data also reveal that accumulating 10,000 steps/day does not guarantee meeting the guidelines in the bout lengths documented to confer the health benefits of physical activity.

Total energy expenditure and physical activity in children treated with home parenteral nutrition

Determining total energy expenditure (TEE) and its components in children treated with home parenteral nutrition (CHPN) under free-living conditions is an important consideration in the assessment of energy requirements and the maintenance of health. The aim of this study was to assess TEE and physical activity in CHPN. Eleven CHPN (three girls and eight boys; median age, 6.0 y; range, 4.5-15.0 y) were compared with 11 healthy children (three girls and eight boys; median age, 6.0 y, range, 4.5-14.0 y) after pairing for sex, age, and weight. Underlying diseases included chronic intractable diarrhea (n = 5), short bowel syndrome (n = 3), and intestinal dysmotility (n = 3). None of these children had inflammatory disease or recent infection when studied. Fat-free mass (FFM), measured by body impedance analysis, fat mass (FM), measured by skinfold thickness, and energy intake were similar between the two groups, suggesting that CHPN had normal body composition and energy intake. Resting energy expenditure (REE), measured by indirect calorimetry, and TEE, assessed by a technique using 24-h heart-rate monitoring calibrated against indirect calorimetry and physical activity using a triaxial accelerometer, were simultaneously recorded and were also similar in the two groups. Sleeping energy expenditure (SEE), expressed per kilogram of FFM, was significantly greater in the CHPN group (median, 0.15; range, 0.10-0.23 kJ/min/kg FFM versus median, 0.12; range, 0.09-0.21 kJ/min/kg FFM for controls; p < 0.05, Wilcoxon rank test). These findings were explained by the high correlation between the energy flow infused by parenteral nutrition and sleeping energy expenditure (p < 0.05, Spearman test) and also-diet induced thermogenesis (p < 0.05 Spearman test). These results suggest that the energy requirements of children on long-term home parenteral nutrition programs do not differ from controls and that cyclic parenteral nutrition does not interfere with physical activity.

Assessing sleeping energy expenditure in children using heart-rate monitoring calibrated against open-circuit indirect calorimetry: a pilot study

Total energy expenditure (EE) can be assessed in children by the heart-rate (HR) monitoring technique calibrated against open-circuit indirect calorimetry (IC). In this technique, sleeping EE is usually estimated as the lowest value of a 30 min resting EE measurement x 0 x 90 to give an average for the total sleeping period. However, sleeping is a dynamic process in which sleeping EE is modulated by the effect of factors such as body movement and different sleep stages. The aim of the present study was to determine a new method to improve the sleeping EE measurement by taking into account body movements during sleep. Twenty-four non-obese children participated in the present study. All subjects passed through a calibration period. HR and EE measured by IC were simultaneously collected during resting, the postprandial period, and during different levels of activity. Different methods for computing sleeping EE (resting with different breakpoints ('flex point' HR with linear regression or 'inflection point' (IP) HR with the third order polynomial regression equation (P3)) were compared with EE measured for least 2.0 h in eight sleeping children. The best method of calculation was then tested in sixteen children undergoing HR monitoring and with a body movement detector. In a subset of eight children undergoing simultaneous sleeping EE measurement by IC and HR, the use of the equation resting when HR<IP and P3 when HR>IP during the sleeping period gave the lowest difference (1 (sd 5.4) %) compared with other methods (linear or polynomial regressions). The new formula was tested in an independent subset of sixteen other children. The difference between sleeping EE computed with the formula resting and sleeping EE computed with resting when HR<IP and the P3 equation when HR>IP during sleeping periods was significant (13 (sd 5.9) %) only for active sleeping subjects (n 6 of 16 subjects). The correlation between the difference in the results from the two methods of calculation and body movements was close (r 0.63, P<0.005, Spearman test) as well as computed sleeping EE (Spearman test, r 0.679, P<0.001), indicating that this new method is reliable for computing sleeping EE with HR monitoring if children are moving during sleep and improves the total EE assessment.

Daily physical activity and ageing

A typical aspect of aging is the increase in variability of a feature within a population, suggesting individual variation in the decline with age. The decline is probably inevitable (predisposed), but some show slower declines than others. Physical activity might be one of the avenues to influence the aging process. There is still a need for validated techniques of estimating habitual physical activity to study the relationship between physical activity and health. Doubly labeled water studies show a decrease in the average proportion of daily energy expenditure for physical activity of about 35% at the age of 20 to 25% at the age of 90. In absolute figures, the activity-induced energy expenditure falls to one third of the initial value over the corresponding age interval. Exercise training does not seem to prevent the age-associated decline in physical activity because of compensation by a decrease in non-training physical activity, in contrast to younger age groups. The effects of the habitual activity level and of exercise on the age-related decline in muscle mass are small if present at all. There is, however, a clear-cut effect of habitual activity and exercise training on muscle function. The positive effects are reflected in muscle fiber type, capillary density, and aerobic capacity. Physical inactivity is an important determinant of disability and mortality risk. Even a recent increase in activity level can have an important effect, although the benefits are also easily lost when the activity level is again reduced.