6-month Physical Activity Intervention Research Articles

Sarcopenia and serum biomarkers of oxidative stress after a 6-month physical activity intervention in women with metastatic breast cancer: results from the ABLE feasibility trial

PurposeSarcopenia has been identified as an important prognostic factor for patients with cancer. This study aimed at exploring the potential associations between a 6-month physical activity intervention and muscle characteristics, sarcopenia, oxidative stress and toxicities in patients with metastatic breast cancer.MethodsWomen newly diagnosed with metastatic breast cancer (N = 49) participated in an unsupervised, personalized, 6-month physical activity intervention with activity tracker. Computerized tomography images at the third lumbar vertebra were analysed at baseline, three months and six months to assess sarcopenia (muscle mass index < 40 cm2/m2) and muscle quality (poor if muscle attenuation < 37.8 Hounsfield Units). Oxidative markers included plasma antioxidant enzymes (catalase, glutathione peroxidase and superoxide dismutase activities), prooxidant enzymes (NADPH oxidase and myeloperoxidase activities) and oxidative stress damage markers (advanced oxidation protein products, malondialdehyde (MDA) and DNA oxidation.ResultsAt baseline 53% (mean age 55 years (SD 10.41)) were sarcopenic and 75% had poor muscle quality. Muscle cross sectional area, skeletal muscle radiodensity, lean body mass remained constant over the six months (p = 0.75, p = 0.07 and p = 0.75 respectively), but differed significantly between sarcopenic and non-sarcopenic patients at baseline and 6-months. Sarcopenic patients at baseline were more likely to have an increase of MDA (p = 0.02) at 6 months. Being sarcopenic during at least one moment during the 6-month study was associated with a higher risk of developing severe toxicities (grade > 2) (p = 0.02).ConclusionsThis study suggests potential benefits of physical activity for maintenance of muscle mass. Sarcopenia can alter many parameters and disturb the pro and antioxidant balance.

A randomized trial of physical activity for cognitive functioning in breast cancer survivors: Rationale and study design of I Can! Improving Cognition After Cancer

IntroductionDifficulties with cognition are extremely common among breast cancer survivors and can significantly impact quality of life, daily functioning, and ability to return to work. One promising intervention is increasing physical activity, as it has been effective in improving cognition in non-cancer populations. Few physical activity intervention trials with cognition outcomes have included cancer survivors. This project builds upon our previous work indicating that increased physical activity can improve objectively measured processing speed and self-reported cognition among breast cancer survivors. MethodsThe I Can! study will examine whether a physical activity intervention improves cognition among 250 post-treatment breast cancer survivors (Stages I-III, <5 years post-treatment) who are reporting cognitive difficulties. This 2-arm randomized controlled trial comparing a 6-month physical activity intervention (Exercise Group) to a health & wellness attention-comparison condition (Health & Wellness Group) will examine intervention effects on cognition (at 3 and 6 months) and maintenance of effects at 12 months. The primary aim is to investigate the impact of exercise on objectively measured processing speed and self-reported cognition. Secondary aims are to investigate maintenance of cognitive changes and examine candidate biological mechanisms and psychological mediators. ConclusionThe I Can! study will contribute to the scientific, public health, and survivorship intervention literature by providing new information on the impact of physical activity for cognitive impairment in breast cancer survivors. Findings from this study will inform guidelines for physical activity to improve the lives of millions of breast cancer survivors.

The differential relationship of an afterschool physical activity intervention on brain function and cognition in children with obesity and their normal weight peers.

Physical activity (PA) is beneficial for cognitive and brain health during preadolescence. Given that childhood obesity (OB) is a public health concern, investigating this effect in children with OB is an important societal consideration. To identify the effects of weight status and PA on neuroelectric indices of executive function in preadolescence. Children were randomly assigned to a PA intervention or a wait-list control group and completed a task that manipulated inhibitory control, while task performance and neuroelectric (P3 component) outcomes were assessed. About 103 children with OB were matched to a sample of 103 normal weight (NW) children based on treatment allocation and demographic variables. Children with OB in the control group demonstrated reduced P3 amplitude from pre- to post-test, meanwhile those with OB in the PA intervention maintained P3 amplitude at post-test compared to pre-test. Additionally, NW children in the PA intervention group showed that decreased visceral adipose tissue corresponded with faster task performance, a relationship not observed in children with OB. These results suggest that a 9-month PA intervention may be particularly beneficial to the cognitive and brain health of children with OB. These results are important to consider given the public health concerns associated with childhood OB.

Skeletal Effects of Nine Months of Physical Activity in Obese and Healthy Weight Children.

Obesity during adolescence has multisystem health consequences. The objective of this work was to determine whether preadolescent overweight/obese children's bones respond to a 9-month physical activity intervention by increasing bone density similar to healthy weight children. Participants included overweight/obese (BMI > 85%) and healthy weight (15% < BMI < 85%) preadolescents (8-9 yr old). Participants in the physical activity group participated in a 9-month physical activity curriculum every day after school. The wait list control group received no intervention. Both groups had overweight/obese children and healthy weight controls. Whole-body bone mineral content, area, and bone mineral apparent density (BMAD) were assessed using dual x-ray absorptiometry) at the beginning and end of the 9-month trial in the physical activity and control group. Overweight/obese preadolescent children had higher BMAD than healthy weight children (P < 0.001 for spine, leg, and whole body). However, the density/weight (BMAD/lean mass) was lower in overweight/obese children than that in healthy weight children, indicating that the density of bones in overweight/obese children may not compensate sufficiently for the excessive load due to weight. The change in BMAD over 9 months was greater in healthy weight children than overweight/obese children in the whole body and leg, but not the lumbar spine. Physical activity caused a site-specific increase in bone density, affecting the legs more than the lumbar spine, but there was no significant difference in the effect of exercise between the healthy weight and the overweight/obese group. The smaller change in BMAD over the 9 months and lower BMAD per unit lean mass in overweight/obese compared with healthy weight children may indicate a slower rate of bone mass accrual, which may have implications for bone health during skeletal growth in obese/overweight children.

Physical Activity, Sleep and Quality of Life in Older Adults: Influence of Physical, Mental and Social Well-being

ABSTRACT Introduction: Physical activity and sleep quality have been consistently associated with quality of life (QOL) in a number of clinical and non-clinical populations. However, mechanisms underlying this relationship are not well understood. The purpose of this study was to longitudinally test a model examining how changes in physical activity and sleep quality, predict physical, mental and social well-being and global QoL across a 6-month exercise trial in a sample of healthy older adults. Methods: Participants (N = 247, mean age 65.4 ± 4.6) wore an accelerometer to assess objective levels of physical activity and completed measures of sleep, physical and mental well-being, social well-being and QOL at baseline and following a 6-month physical activity intervention. Relationships among model constructs were examined over time using panel analysis within a covariance-modeling framework. Results: The hypothesized model provided a good model-data fit (χ2 = 58.77, df = 41, p = .036); CFI = 0.98; SRMR = 0.05; RMSEA = 0.04). At both time-points, physical activity and sleep quality were significantly correlated. Sleep quality indirectly influenced QOL via physical, mental and social well-being (QOL R2 = .47, p < .001). These relationships were also supported across time at month 6 (QOL R2 = .50, p < .001). Neither physical activity nor sleep quality directly influenced QOL. Conclusion: Our results support a novel sleep and QOL model that may inform the design of health interventions to promote sleep quality, and thereby influencing QOL by targeting physical activity and modifiable mediators of physical, mental and social health. Our findings may have significant implications for older adults as well as clinical populations that report compromised sleep, impaired health related and global QOL.

Physical activity preferences before and after participation in a 6-month physical activity intervention among women with metastatic breast cancer.

This secondary analysis of the ABLE Trial (ClinicalTrials.gov NCT03148886) aimed to assess physical activity preferences before and after a 6-month physical activity intervention for women recently diagnosed with metastatic breast cancer and to investigate demographic and clinical correlates of these preferences. Forty-nine patients participated in the ABLE Trial, a single-arm, unsupervised 6-month physical activity intervention with activity trackers. At baseline and 6months, physical activity preferences, physical activity level, clinical variables, demographics and social vulnerability were assessed. At baseline, 49 participants were included, among whom 85% were interested in receiving physical activity counselling and 89% were interested in following a physical activity programme designed for metastatic breast cancer. At the end of the study, more participants preferred practising in a community fitness centre (66%) rather than at home (19% vs. 44% at baseline, p=.03). A higher social vulnerability score and not being treated by chemotherapy at baseline were significantly associated with lower desire to receive physical activity counselling (p=.01 and p=.04 respectively). This study will help design future studies within patients with metastatic breast cancer in accordance with their preferences. Designing tailored physical activity interventions according to the participant's preferences may be one key to success for adherence.

Classroom-based physical activity improves children's math achievement - A randomized controlled trial.

This RCT investigated the effect on children of integrating physical activity (PA) into math lessons. The primary outcome was math achievement and the secondary outcomes were executive functions, fitness and body mass index. Twelve Danish schools were randomized to either an intervention group or a control group. A total of 505 children with mean age 7.2 ± 0.3 years were enrolled in the study. Change in math achievement was measured by a 45-minute standardized math test, change in executive function by a modified Eriksen flanker task, aerobic fitness by the Andersen intermittent shuttle-run test, and body mass index by standard procedures. PA during the math lessons and total PA (including time spent outside school) were assessed using accelerometry (ActiGraph, GT3X and GT3X+). Children in the intervention group improved their math score by 1.2 (95% CI 0.3; 2.1) more than the control group (p = 0.011) and had a tendency towards a higher change in physical activity level during math lessons of 120,4 counts/min (95% CI -9.0;249.8.2, p = 0.067). However, the intervention did not affect executive functions, fitness or body mass index. Participation in a 9-month PA intervention (from 2012–2013) improved math achievement among elementary school children. If replicated, these findings would suggest that implementation of physical activity in school settings could lead to higher academic achievement.

A Personalized Physical Activity Program With Activity Trackers and a Mobile Phone App for Patients With Metastatic Breast Cancer: Protocol for a Single-Arm Feasibility Trial.

BackgroundAbout 5% of breast cancer cases are metastatic at diagnosis, and 20%-30% of localized breast cancer cases become secondarily metastatic. Patients frequently report many detrimental symptoms related to metastasis and treatments. The physical, biological, psychological, and clinical benefits of physical activity during treatment in patients with localized breast cancer have been demonstrated; however, limited literature exists regarding physical activity and physical activity behavior change in patients with metastatic breast cancer.ObjectiveThe primary objective of this study is to assess the feasibility of a 6-month physical activity intervention with activity trackers in patients with metastatic breast cancer (the Advanced stage Breast cancer and Lifestyle Exercise, ABLE Trial). Secondary objectives are to examine the effects of physical activity on physical, psychological, anthropometrics, clinical, and biological parameters.MethodsWe plan to conduct a single-center, single-arm trial with 60 patients who are newly diagnosed with metastatic breast cancer. Patients will receive an unsupervised and personalized 6-month physical activity program that includes an activity tracker Nokia Go and is based on the physical activity recommendation. Patients will be encouraged to accumulate at least 150 minutes per week of moderate-to-vigorous intensity physical activity. Baseline and 6-month assessments will include anthropometric measures, functional tests (eg, 6-minute walk test and upper and lower limb strength), blood draws, patient-reported surveys (eg, quality of life and fatigue), and clinical markers of tumor progression (eg, Response Evaluation Criteria In Solid Tumors criteria).ResultsData collection occurred between October 2016 and January 2018, and the results are expected in August 2018.ConclusionsThe ABLE Trial will be the first study to assess the feasibility and effectiveness of an unsupervised and personalized physical activity intervention performed under real-life conditions with activity trackers in patients with metastatic breast cancer.Trial RegistrationClinicalTrials.gov NCT03148886; https://clinicaltrials.gov/ct2/show/NCT03148886 (Accessed by WebCite at http://www.webcitation.org/71yabi0la)Registered Report IdentifierRR1-10.2196/10487

Obesity, Visceral Adipose Tissue, and Cognitive Function in Childhood

To evaluate the effects of a 9-month physical activity intervention on changes in adiposity and cognitive control based on pretrial weight status (ie, healthy weight vs obese) in children. Participants included obese (n = 77) and matched healthy-weight (n = 77) preadolescents (8-9 years) who participated in a 9-month physical activity randomized controlled trial. Cognitive function was assessed with an inhibitory control task (modified flanker task). After the 9-month physical activity intervention, participants exhibited a reduction in adiposity. In contrast, children in the waitlist-control condition, particularly children identified as obese pretrial, gained visceral adipose tissue (P= .008). Changes in visceral adipose tissue were related to changes in cognitive performance, such that the degree of reduction in visceral adipose tissue directly related to greater gains in inhibitory control, particularly among obese intervention participants (CI -0.14, -0.04; P= .001). Participation in a daily physical activity program not only reduces adiposity but also improves children's cognitive function as demonstrated by an inhibitory control task. Furthermore, these findings reveal that the benefits of physical activity to improvements in cognitive function are particularly evident among children who are obese. ClinicalTrials.gov: NCT01334359 and NCT01619826.

Using Feedback to Promote Physical Activity: The Role of the Feedback Sign.

BackgroundProviding feedback is a technique to promote health behavior that is emphasized by behavior change theories. However, these theories make contradicting predictions regarding the effect of the feedback sign—that is, whether the feedback signals success or failure. Thus, it is unclear whether positive or negative feedback leads to more favorable behavior change in a health behavior intervention.ObjectiveThe aim of this study was to examine the effect of the feedback sign in a health behavior change intervention.MethodsData from participants (N=1623) of a 6-month physical activity intervention was used. Participants received a feedback email at the beginning of each month. Feedback was either positive or negative depending on the participants’ physical activity in the previous month. In an exploratory analysis, change in monthly step count averages was used to evaluate the feedback effect.ResultsThe feedback sign did not predict the change in monthly step count averages over the course of the intervention (b=−84.28, P=.28). Descriptive differences between positive and negative feedback can be explained by regression to the mean.ConclusionsThe feedback sign might not influence the effect of monthly feedback emails sent out to participants of a large-scale physical activity intervention. However, randomized studies are needed to further support this conclusion. Limitations as well as opportunities for future research are discussed.

Effects of the FITKids Randomized Controlled Trial on Cognitive Control and Conflict Monitoring in Children

PURPOSE: We investigated the influence of a 9-month physical activity intervention (FITKids: NCT01619826, NCT01334359) on cognitive control and conflict monitoring. METHODS: Three hundred eight preadolescent children (8-9 years old) were randomized into an afterschool physical activity intervention (n=139) or a wait-list control group (n=169). The FITKids intervention occurred following every school day and provided a sum of 70-minutes of moderate-to-vigorous physical activity per session. All children completed a fitness assessment and a cognitive control task (i.e., flanker task) at pre- and post-test. Event-related brain potentials (ERPs) were recorded during flanker performance to determine neuroelectric underpinnings of frontally mediated changes in conflict monitoring (i.e., error-related negativity or ERN). RESULTS: Results revealed greater improvements in fitness from pre- to post-test for the intervention group (1.8 mL/kg/min; 5.4% change) compared to the control group (0.6 mL/kg/min; 2.1% change) [t(306)=2.3, p=0.02]. Further, increased performance was observed for the flanker task, requiring variable amounts of cognitive control, with greater change for the intervention group (9.3% accuracy; -8.5 omission errors, -2.0 omission error runs) compared to the control group (6% accuracy; -4.1 omission errors, -0.7 omission error runs) [F’s(1, 306)≥6.1, p’s≤0.02]. Additionally, results revealed larger ERN amplitude at post-test (-6.3 μV) compared to pre-test (-5.0 μV), only for the wait-list group [F’s(1, 306)≥9.6, p’s≤0.01] with no such change observed for the intervention group (pre-test: -5.7 μV; post-test: -5.7 μV) [F’s(1, 306)≤0.6, p’s≥0.46], suggesting greater cognitive efficiency in that no additional adjustments in neural indices of performance monitoring were observed to underlie improved performance at post-test. Lastly, a dose-response relation was observed for children in the intervention such that greater improvements in cardiorespiratory fitness were related to greater reductions in ERN amplitude (r=.20, p=0.02). CONCLUSIONS: These findings demonstrate that daily physical activity not only serves to improve fitness but also facilitates behavioral and functional neural processes associated with effective conflict monitoring in young children.

Perceived changes to quality of life indicators following a physical activity intervention for recovering cancer patients: A qualitative study.

The aim of this study was to examine the perceived changes to the quality of life (QoL) for a group of recovering cancer patients, following 6 months of physical activity.Background Evidence suggests that physical activity can improve the QoL of recovering cancer patients, reducing many of the side-effects of cancer and its related treatments, including depression, anxiety, chronic fatigue and improve physical and psychological health. Method A qualitative study with 14 mixed site cancer patients aged 43-70 (12 women, 2 men). The intervention was in 2 parts the first part was an 8-week physical activity programme, the second part related to a period of non-supervised, physical activity for 4 months (6 months in total). The Programme took place at a university in the South West of England. Semi-structured interviews with patients took place 3 times over 6 months. A grounded theory approach was used to analyse the data.Results We found that prior to the 6-month physical activity intervention many of the patients were anxious about being able to complete the initial 8 week programme. Anxieties related to low self-esteem and the chronic fatigue resulting from their cancer treatment. Consequently several patients expressed concerns about their ability to help themselves self-manage their recovery through physical activity. On completion of the intervention the majority of patients reported improvements in their perceived QoL relating to their ability to self-manage, their self-efficacy, energy levels, along with decreases in chronic fatigue.Conclusion Our study has provided valuable insights into how the perceived QoL of a group of recovering cancer patients can be improved through a combined 6-month period of supervised and independent physical activity. These findings serve as further evidence of the effectiveness of a person centred healthcare approach for recovering cancer patients.

Abstract P137: Examining the Effect of the Accumulation of Physical Activity on Blood Pressure in a Physical Activity Intervention for Community Dwelling Older Adults

Background: High blood pressure is one of the most common health conditions experienced by US older adults. Hypertension leads to heart disease, CVD incidence, stroke, and death. In older adults, community based physical activity (PA) interventions have been shown to significantly decrease systolic and diastolic blood pressure. The American Heart Association Physical Activity Guidelines recommend that adults accumulate at least 150 minutes of moderate-vigorous intensity physical activity (MVPA) per week in order to obtain substantial health benefits. It is not clear whether accumulation of total minutes of physical activity is more important for significant changes in cardiovascular health, including reductions in blood pressure levels, or whether the intensity of the physical activity is important. New physical activity assessment techniques allow us to assess daily minutes of intensity outside of the clinic environment. Study Objectives: The objective of this study was to assess the effects of total accumulation of PA, independent of time spent in MVPA, on changes in blood pressure in older adults participating in a 6-month physical activity intervention. Methods: Study data are from a multilevel physical activity intervention (MIPARC) for older adults. Residents over the age of 65 years (N=307, mean age 84) were recruited from 11 retirement communities in San Diego. Study evaluation included collection of blood pressure measures and 6 day hip-worn accelerometry data. Change in blood pressure (dependent variable) and PA (intensity and total) from baseline to 6 months and 6 months to 12 months were examined. To account for within person and within group clustering, hierarchical longitudinal mixed effect models were used. Results: Increases in total PA counts was related to significant decreases in systolic blood pressure over the 12-month intervention period, after adjusting for minutes of time spent in MVPA (p&lt;.005). Conclusions: Evidence is mixed on the intensity of PA needed for older adults to experience significant health benefits, including reducing blood pressure. The results of this study suggest that for older adults, the total accumulation of PA at any intensity, is more important than PA at moderate to vigorous intensities. These findings have important implications for the design of PA interventions and PA prescriptions for older adults. More research is needed in older adult populations to examine if MVPA is beneficial to older adults, or if the relationship varies by an individual’s cardiovascular health.

Stand up for health—avoiding sedentary behaviour might lengthen your telomeres: secondary outcomes from a physical activity RCT in older people

BackgroundTelomere length has been associated with a healthy lifestyle and longevity. However, the effect of increased physical activity on telomere length is still unknown. Therefore, the aim was to study...

Impact of the FITKids Physical Activity Intervention on Adiposity in Prepubertal Children

To investigate the effect of a 9-month physical activity intervention on cardiorespiratory fitness and adiposity among prepubertal children. Prepubertal children (8- to 9-year-olds, N = 220, 103 girls) were randomly assigned to a 9-month physical activity intervention or a control group. The intervention provided 70 minutes (5 days/week) of moderate to vigorous physical activity. Maximum oxygen consumption (Vo2max percentile) and dual-energy radiograph absorptiometry measured cardiorespiratory fitness and adiposity, respectively. Intention-to-treat analysis was performed to assess baseline and follow-up cardiorespiratory fitness, percentage fat mass (%FM), percentage central fat mass (%CFM), and estimated visceral adipose tissue (VAT) area. The intervention group increased in cardiorespiratory fitness (5.4th percentile; 95% confidence interval [CI], 1.8 to 8.9) and decreased in %FM (-0.7%; 95% CI, -1.1 to -0.4) and %CFM (-1.3%; 95% CI, -1.9 to -0.7). Reductions in %FM were evident for both nonoverweight (-0.62%; 95% CI, -1.07 to -0.17) and overweight or obese (-0.86%; 95% CI,-1.46 to -0.25) intervention participants. Conversely, the control group displayed no change in cardiorespiratory fitness while exhibiting increases in %FM (0.4%; 95% CI, 0.1 to 0.7), %CFM (0.6; 95% CI, 0.1 to 1.1), and VAT area (3.0 cm(2); 95% CI, 1.6 to 4.4). Nonoverweight control participants increased in %FM (0.52%; 95% CI, 0.13 to 0.91), and their overweight and obese counterparts increased in VAT (4.76 cm(2); 95% CI, 1.90 to 7.63). The physical activity intervention improved cardiorespiratory fitness, reduced %FM, and prevented accumulation of %CFM among prepubertal children with varying adiposity levels. These findings provide support for daily physical activity recommendations to prevent excess fat mass accumulation in childhood.

The FABS trial: A randomised control trial of the effects of a 6-month physical activity intervention on adherence and long-term physical activity and self-efficacy in older adults with memory complaints

ObjectiveThe aim of this study is to assess in older adults with memory complaints, the effects of a 6-month home-based physical activity (PA) intervention on short-term adherence, short and long-term self-efficacy and the predictors of adherence. MethodsParticipants with memory complaints with or without mild cognitive impairment (MCI) were recruited from Perth, Western Australia between May 2004 and July 2006 and randomly assigned to a control or an intervention group. The intervention group received a 6-month PA programme and recorded sessions on a diary. Pedometer readings, questionnaires, and physical and cognitive measures were completed at 0, 6, 12 and 18months. ResultsOne hundred and seventy participants started the study. Retention rates were similar for both groups at all time-points however retention was higher for men than women (P<0.01). Adherence to the prescribed PA was 72.8% (95% CI, 70.8 74.9%). Men had higher adherence rate than women (P<0.001). Those with and without MCI had similar adherence. Compared to controls self-efficacy was higher in the intervention group after 6months only (P<0.01). ConclusionsOlder adults with memory complaints, with or without MCI, can successfully participate in and enjoy home-based PA programmes. Long-term adherence to such interventions may require continued support and increased self-efficacy. (Trial registration: ACTRN012605000136606.)

Effect of a 6-month school-based physical activity program on body composition and physical fitness in lean and obese schoolchildren

Few studies have investigated the impact of school-based physical activity interventions on anthropometric characteristics concomitantly with aerobic and anaerobic capacities in young children. The present study aimed to assess the effect of a 6-month physical activity program on body composition and physical fitness among primary schoolchildren. Four hundred fifty-seven children aged 6 to 10 years were randomly assigned to the intervention group (229 children) or observational group (228 children). Participants' height and weight were assessed, and obesity was determined using French reference curves for BMI. The sum of the four skinfolds and fat-free mass were determined. Ground tests were used to assess aerobic (20-m shuttle run test) and anaerobic (cycling peak power) fitness before and after a 6-month physical activity intervention. The anthropometric modifications obtained over the 6 months cannot be attributed to the intervention as the ANOVA revealed no group effect (intervention vs. group). However, anaerobic and aerobic fitness were significantly improved, thanks to the program in both lean and obese children. A 6-month school-based physical activity intervention in 6- to 10-year-old children did not yield positive anthropometric improvements, but appears effective in terms of aerobic and anaerobic physical fitness. Two physical activity sessions per week in addition to standard physical education classes in primary schoolchildren bring effective results for the prevention of childhood obesity.

Impact of Baseline BMI upon the Success of Latina Participants Enrolled in a 6-Month Physical Activity Intervention

High rates of obesity in Latinas highlight the need to determine if physical activity interventions are equally effective across the body mass index (BMI) range. Thus, this study assessed how BMI impacts success of Spanish-speaking Latinas in a culturally and linguistically adapted theory-based physical activity intervention (N = 45). Longitudinal regression models tested the relationship between baseline BMI and outcomes. Overall, a trend for a negative association was found between baseline BMI and self-reported physical activity and theoretical constructs targeted by the intervention over time. For example, someone with a 25 kg/m2 BMI would report, on average, 27.5 more minutes/week of activity compared to someone with a 30 kg/m2 BMI at followup. Furthermore, higher baseline BMI was significantly associated with lower self-efficacy, behavioral and cognitive processes of change, and family social support over time. These findings suggest that participants with higher BMI may need additional intervention to promote physical activity.

Reducing Attrition in Physical Activity Programs for Older Adults

This study investigated attrition in a 6-month physical activity intervention for older adults. The program was based on the social-cognitive theory incorporating self-efficacy factors. Two hundred forty-eight insufficiently active 65- to 74-year-olds were recruited from the Australian federal electoral roll. The intervention comprised walking and strength and flexibility exercises and was conducted in 30 local neighborhoods where the participants resided. Characteristics of individuals lost to attrition (n = 86, 35%) were compared with those of program completers (n = 162, 65%). Logistic-regression analysis showed that those lost to attrition came from areas of lower socioeconomic status, were overweight and less physically active, and had lower walking self-efficacy scores and higher loneliness scores. The results suggest that early assessment of these characteristics should be undertaken to identify individuals at risk of attrition, to improve retention, and to avoid potential bias.

Physical activity and physical self-concept among sedentary adolescent females: An intervention study

Objectives Physical activity (PA) has been promoted as a means of enhancing self-concept, yet the evidence for this connection is far from compelling. In particular, experimental research investigating this association during adolescence, a period during which many youth struggle to maintain a positive self-image, is noticeably lacking. This study investigates the impact on self-concept of a 9-month PA intervention among sedentary adolescent females. Design This study was a controlled trial, in which measures of self-concept were obtained before, during, and following a 9-month school-based intervention to promote physical activity in sedentary adolescent females. Changes among the intervention group were analyzed relative to changes among a non-random comparison group. Method Intervention participants engaged in supervised activity 4 times/week and received didactic instruction 1 day/week promoting activity outside of school. Self-concept, PA participation, and cardiovascular fitness were assessed before, mid-way through, and after the 9-month intervention. Results The intervention had a significant positive impact on participation in vigorous activity and cardiovascular fitness. The intervention did not significantly influence any of the self-concept dimensions overall. There was, however, a three-way interaction such that there was an increase in global physical self-concept among those intervention participants who increased cardiovascular fitness. Conclusions These findings indicate that a PA intervention among sedentary adolescent females enhanced global physical self-concept for a subset of intervention participants who manifested positive changes in fitness.