Associations between metabolic syndrome components and markers of inflammation in Welsh school children.

We investigated the multivariate dimensionality and strength of the relationship between metabolic syndrome (MetS) and inflammation in children. Caucasian school children (N = 229; 12-14 years) from Wales were tested on several health indicators including measures of body composition, inflammation, fasting glucose regulation, blood pressure, and lipids. The multivariate association between MetS and inflammation was investigated via canonical correlation analysis. Data were corrected for non-normality by log transformation, and sex-specific z-scores computed for variables where there was a significant sex difference. Structure r's were interpreted to determine the dimensions of MetS and inflammation responsible for significant canonical variates. The overall multivariate association between MetS and inflammation was significant (Wilks' Lambda = 0.54, p < 0.001). The relationship was explained primarily by the waist circumference dimension of MetS (CC = 0.87) and inflammatory markers of fibrinogen (CC = 0.52) and C-reactive protein (CC = 0.50). The pattern of results was similar regardless of whether variables were adjusted for sex differences. CONCLUSION: Central adiposity is the strongest predictor of the inflammatory aspect of cardiovascular disease risk in Caucasian adolescents. Future research into MetS and cardiometabolic risk should consider multivariate statistical approaches, in order to identify the separate contributions of each dimension in interrelationships and to identify which dimensions are influenced by preventive interventions. What is Known: • Metabolic syndrome (MetS) is associated with increased risk of cardiovascular disease (CVD) and type 2 diabetes. Markers of inflammation are also potential predictors of later development of CVD and type 2 diabetes. • The contribution of individual markers in interrelationships between MetS and inflammation is unknown. What is New: • We uniquely demonstrate that within a multivariate model, waist circumference is the primary link between MetS variables and markers of inflammation in children. • Waist circumference may therefore be a useful population-level screening tool to identify future risk of CVD.

Effectiveness of active school transport interventions: a systematic review and update.

BACKGROUND: Active school transport (AST) is a promising strategy to increase children's physical activity. A systematic review published in 2011 found large heterogeneity in the effectiveness of interventions in increasing AST and highlighted several limitations of previous research. We provide a comprehensive update of that review. METHODS: Replicating the search of the previous review, we screened the PubMed, Web of Science, Cochrane, Sport Discus and National Transportation Library databases for articles published between February 1, 2010 and October 15, 2016. To be eligible, studies had to focus on school-aged children and adolescents, include an intervention related to school travel, and report a measure of travel behaviors. We assessed quality of individual studies with the Effective Public Health Practice Project quality assessment tool, and overall quality of evidence with the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach. We calculated Cohen's d as a measure of effect size. RESULTS: Out of 6318 potentially relevant articles, 27 articles reporting 30 interventions met our inclusion criteria. Thirteen interventions resulted in an increase in AST, 8 found no changes, 4 reported inconsistent results, and 5 did not report inferential statistics. Cohen's d ranged from -0.61 to 0.75, with most studies reporting "trivial-to-small" positive effect sizes. Three studies reported greater increases in AST over longer follow-up periods and two Safe Routes to School studies noted that multi-level interventions were more effective. Study quality was rated as weak for 27/30 interventions (due notably to lack of blinding of outcome assessors, unknown psychometric properties of measurement tools, and limited control for confounders), and overall quality of evidence was rated as low. Evaluations of implementation suggested that interventions were limited by insufficient follow-up duration, incomplete implementation of planned interventions, and limited access to resources for low-income communities. CONCLUSIONS: Interventions may increase AST among children; however, there was substantial heterogeneity across studies and quality of evidence remains low. Future studies should include longer follow-ups, use standardized outcome measures (to allow for meta-analyses), and examine potential moderators and mediators of travel behavior change to help refine current interventions. TRIAL REGISTRATION: Registered in PROSPERO: CRD42016033252.

How fast is fast enough? Walking cadence (steps/min) as a practical estimate of intensity in adults: a narrative review.

BACKGROUND: Cadence (steps/min) may be a reasonable proxy-indicator of ambulatory intensity. A summary of current evidence is needed for cadence-based metrics supporting benchmark (standard or point of reference) and threshold (minimums associated with desired outcomes) values that are informed by a systematic process. OBJECTIVE: To review how fast, in terms of cadence, is enough, with reference to crafting public health recommendations in adults. METHODS: A comprehensive search strategy was conducted to identify relevant studies focused on walking cadence and intensity for adults. Identified studies (n=38) included controlled (n=11), free-living observational (n=18) and intervention (n=9) designs. RESULTS: There was a strong relationship between cadence (as measured by direct observation and objective assessments) and intensity (indirect calorimetry). Despite acknowledged interindividual variability, ≥100 steps/min is a consistent heuristic (e.g, evidence-based, rounded) value associated with absolutely defined moderate intensity (3 metabolic equivalents (METs)). Epidemiological studies report notably low mean daily cadences (ie, 7.7 steps/min), shaped primarily by the very large proportion of time (13.5 hours/day) spent between zero and purposeful cadences (<60 steps/min) at the population level. Published values for peak 1-min and 30-min cadences in healthy free-living adults are >100 and >70 steps/min, respectively. Peak cadence indicators are negatively associated with increased age and body mass index. Identified intervention studies used cadence to either prescribe and/or quantify ambulatory intensity but the evidence is best described as preliminary. CONCLUSIONS: A cadence value of ≥100 steps/min in adults appears to be a consistent and reasonable heuristic answer to 'How fast is fast enough?' during sustained and rhythmic ambulatory behaviour. TRIAL REGISTRATION NUMBER: NCT02650258.

Impact of physical activity domains on subsequent physical activity in youth: a 5-year longitudinal study.

This study evaluates how domains of physical activity (PA) in youth predict later PA and assesses factors influencing changes in sports participation. Young people from the Children's Sport Participation and Physical Activity study (n = 873; baseline age 10-18 years; 30.4% male) completed self-report surveys in 2009 and 2014. In a multiple linear regression analysis, participation frequency in club sport (ß = 0.18) and extracurricular sport (ß = 0.13) significantly predicted PA 5 years later, adjusted for age, sex and urban/rural classification (P < 0.01). Overall, rates of regular (at least once per week) youth sports participation were high (males 79.3-85.5%; females 74.8-83.2%). Uptake and dropout of specific sports varied widely. Despite high levels of migration into and out of Gaelic games, they remained popular at follow-up. Weight training was the only sport that increased in both sexes (P < 0.05). Fitness, friends and enjoyment were top motivations for taking up a new sport. Other commitments, a lack of interest and time were important factors leading to sports dropout. PA promotion strategies should include youth sport, take into consideration what sports are attractive to young people and address reasons for uptake and dropout.

Validity of a two-item physical activity questionnaire for assessing attainment of physical activity guidelines in youth.

BACKGROUND: As physical activity is important for health and well-being, it is essential to monitor population prevalence of physical activity. Surveillance is dependent on the use of valid and reliable measurement tools. The PACE+ questionnaire is used globally in youth and has acceptable reliability; however it has not been validated in a European sample. The purpose of this study is to validate this instrument in a sample of 10-18 year old Irish youth. METHODS: Participants (n = 419, 45.7 % male) completed the PACE+ two-item questionnaire and were asked to wear an Actigraph accelerometer for eight consecutive days. Freedson cut-points were used to estimate moderate to vigorous physical activity from accelerometer counts. Analyses compared self-report and accelerometry data in participants with (1) ≥5 and (2) seven valid accelerometer days. Calculations were performed for the whole sample, and were stratified by sex and school level (primary; post-primary). RESULTS: Spearman correlations between self-reported physical activity levels and accelerometry derived minutes of moderate-to-vigorous physical activity per day were small (r = 0.27; seven valid days) to moderate (r = 0.34; ≥5 valid days). Higher correlations were found in older participants (post-primary r = 0.39; primary r = 0.24) and females (r = 0.39; males r = 0.27) using ≥5 valid days. The agreement level was high (68-96 %). The accuracy of classifying those not meeting the guidelines (specificity) was moderate to high (59-100 %). CONCLUSIONS: The PACE+ self-report instrument has acceptable validity for assessing non-achievement of the adolescent physical activity recommendations. The validity is higher in females and increases with age. The continued use of the tool is recommended and will allow for comparability between studies, tracking of physical activity over time including trends in youth population prevalence.

Stride rate and walking intensity in healthy older adults.

PURPOSE: The study investigated (a) walking intensity (stride rate and energy expenditure) under three speed instructions; (b) associations between stride rate, age, height, and walking intensity; and (c) synchronization between stride rate and music tempo during overground walking in a population of healthy older adults. METHODS: Twenty-nine participants completed 3 treadmill-walking trials and 3 overground-walking trials at 3 self-selected speeds. Treadmill VO2 was measured using indirect calorimetry. Stride rate and music tempo were recorded during overground-walking trials. RESULTS: Mean stride rate exceeded minimum thresholds for moderate to vigorous physical activity (MVPA) under slow (111.41 ± 11.93), medium (118.17 ± 11.43), and fast (123.79 ± 11.61) instructions. A multilevel model showed that stride rate, age, and height have a significant effect (p < .01) on walking intensity. CONCLUSIONS: Healthy older adults achieve MVPA with stride rates that fall below published minima for MVPA. Stride rate, age, and height are significant predictors of energy expenditure in this population. Music can be a useful way to guide walking cadence.

A Comparison of Objectively Measured Free-Living Physical Behaviour in Adults with and without Lower Limb Amputation.

Objectively monitored free-living physical behaviours of adults with and without lower limb amputation (LLA) were compared. METHODS: 57 adults with LLA wore an activPAL3™ for 8 days. A comparison data set (n = 57) matched on gender, age and employment status was used. Variables included: time sitting; standing; stepping; sit-to-stand transitions; step count and cadence. Comparisons were made between adults with and without LLA and between gender, level and cause of amputation. RESULTS: Participants with LLA due to trauma versus circulatory causes were less sedentary and more active; however, no difference in physical behaviour was recorded across gender or level of amputation. Participants with LLA spent more time sitting (p < 0.001), less time standing and stepping (p < 0.001) and had a lower step count (p < 0.001). Participants with LLA took more steps in cadence bands less than 100 steps·min-1 and fewer steps in cadence bands greater than 100 steps·min-1 compared to participants without LLA. CONCLUSIONS: People with LLA were less active and more sedentary than people without LLA and participated in less activity at a moderate or higher intensity when matched on age, gender and employment. Interventions are needed to promote active lifestyles in this population.

Predicting active school travel: the role of planned behavior and habit strength.

BACKGROUND: Despite strong support for predictive validity of the theory of planned behavior (TPB) substantial variance in both intention and behavior is unaccounted for by the model's predictors. The present study tested the extent to which habit strength augments the predictive validity of the TPB in relation to a currently under-researched behavior that has important health implications, namely children's active school travel. METHOD: Participants (N = 126 children aged 8-9 years; 59 % males) were sampled from five elementary schools in the west of Scotland and completed questionnaire measures of all TPB constructs in relation to walking to school and both walking and car/bus use habit. Over the subsequent week, commuting steps on school journeys were measured objectively using an accelerometer. Hierarchical multiple regressions were used to test the predictive utility of the TPB and habit strength in relation to both intention and subsequent behavior. RESULTS: The TPB accounted for 41 % and 10 % of the variance in intention and objectively measured behavior, respectively. Together, walking habit and car/bus habit significantly increased the proportion of explained variance in both intention and behavior by 6 %. Perceived behavioral control and both walking and car/bus habit independently predicted intention. Intention and car/bus habit independently predicted behavior. CONCLUSIONS: The TPB significantly predicts children's active school travel. However, habit strength augments the predictive validity of the model. The results indicate that school travel is controlled by both intentional and habitual processes. In practice, interventions could usefully decrease the habitual use of motorized transport for travel to school and increase children's intention to walk (via increases in perceived behavioral control and walking habit, and decreases in car/bus habit). Further research is needed to identify effective strategies for changing these antecedents of children's active school travel.

The effect of a school-based active commuting intervention on children's commuting physical activity and daily physical activity.

OBJECTIVE: To investigate the effect of a school-based intervention called Travelling Green (TG) on children's walking to and from school and total daily physical activity. METHOD: A quasi-experiment with 166 Scottish children (8-9 years) was conducted in 2009. One group (n=79) received TG and another group (n=87) acted as a comparison. The intervention lasted 6 weeks and consisted of educational lessons and goal-setting tasks. Steps and MVPA (daily, a.m. commute, p.m. commute, and total commute) were measured for 5 days pre- and post-intervention using accelerometers. RESULTS: Mean steps (daily, a.m., p.m., and total commute) decreased from pre- to post-intervention in both groups (TG by 901, 49, 222, and 271 steps/day and comparison by 2528, 205, 120, and 325 steps/day, respectively). No significant group by time interactions were found for a.m., p.m., and total commuting steps. A medium (partial eta squared=0.09) and significant (p<0.05) group by time interaction was found for total daily steps. MVPA results were similar to step results. CONCLUSIONS: TG has a little effect on walking to and from school. However, for total daily steps and daily MVPA, TG results in a smaller seasonal decrease than for children who do not receive the intervention.

Increasing older adults' walking through primary care: results of a pilot randomized controlled trial.

BACKGROUND: Physical activity can positively influence health for older adults. Primary care is a good setting for physical activity promotion. OBJECTIVE: To assess the feasibility of a pedometer-based walking programme in combination with physical activity consultations. DESIGN: Two-arm (intervention/control) 12-week randomized controlled trial with a 12-week follow-up for the intervention group. SETTING: One general practice in Glasgow, UK. PARTICIPANTS: PARTICIPANTS were aged ≥65 years. The intervention group received two 30-minute physical activity consultations from a trained practice nurse, a pedometer and a walking programme. The control group continued as normal for 12 weeks and then received the intervention. Both groups were followed up at 12 and 24 weeks. OUTCOME MEASURES: Step counts were measured by sealed pedometers and an activPALTM monitor. Psychosocial variables were assessed and focus groups conducted. RESULTS: The response rate was 66% (187/284), and 90% of those randomized (37/41) completed the study. Qualitative data suggested that the pedometer and nurse were helpful to the intervention. Step counts (activPAL) showed a significant increase from baseline to week 12 for the intervention group, while the control group showed no change. Between weeks 12 and 24, step counts were maintained in the intervention group, and increased for the control group after receiving the intervention. The intervention was associated with improved quality of life and reduced sedentary time. CONCLUSIONS: It is feasible to recruit and retain older adults from primary care and help them increase walking. A larger trial is necessary to confirm findings and consider cost-effectiveness.

How many steps/day are enough? for children and adolescents.

Worldwide, public health physical activity guidelines include special emphasis on populations of children (typically 6-11 years) and adolescents (typically 12-19 years). Existing guidelines are commonly expressed in terms of frequency, time, and intensity of behaviour. However, the simple step output from both accelerometers and pedometers is gaining increased credibility in research and practice as a reasonable approximation of daily ambulatory physical activity volume. Therefore, the purpose of this article is to review existing child and adolescent objectively monitored step-defined physical activity literature to provide researchers, practitioners, and lay people who use accelerometers and pedometers with evidence-based translations of these public health guidelines in terms of steps/day. In terms of normative data (i.e., expected values), the updated international literature indicates that we can expect 1) among children, boys to average 12,000 to 16,000 steps/day and girls to average 10,000 to 13,000 steps/day; and, 2) adolescents to steadily decrease steps/day until approximately 8,000-9,000 steps/day are observed in 18-year olds. Controlled studies of cadence show that continuous MVPA walking produces 3,300-3,500 steps in 30 minutes or 6,600-7,000 steps in 60 minutes in 10-15 year olds. Limited evidence suggests that a total daily physical activity volume of 10,000-14,000 steps/day is associated with 60-100 minutes of MVPA in preschool children (approximately 4-6 years of age). Across studies, 60 minutes of MVPA in primary/elementary school children appears to be achieved, on average, within a total volume of 13,000 to 15,000 steps/day in boys and 11,000 to 12,000 steps/day in girls. For adolescents (both boys and girls), 10,000 to 11,700 may be associated with 60 minutes of MVPA. Translations of time- and intensity-based guidelines may be higher than existing normative data (e.g., in adolescents) and therefore will be more difficult to achieve (but not impossible nor contraindicated). Recommendations are preliminary and further research is needed to confirm and extend values for measured cadences, associated speeds, and MET values in young people; continue to accumulate normative data (expected values) for both steps/day and MVPA across ages and populations; and, conduct longitudinal and intervention studies in children and adolescents required to inform the shape of step-defined physical activity dose-response curves associated with various health parameters.

How many steps/day are enough? For adults.

Physical activity guidelines from around the world are typically expressed in terms of frequency, duration, and intensity parameters. Objective monitoring using pedometers and accelerometers offers a new opportunity to measure and communicate physical activity in terms of steps/day. Various step-based versions or translations of physical activity guidelines are emerging, reflecting public interest in such guidance. However, there appears to be a wide discrepancy in the exact values that are being communicated. It makes sense that step-based recommendations should be harmonious with existing evidence-based public health guidelines that recognize that "some physical activity is better than none" while maintaining a focus on time spent in moderate-to-vigorous physical activity (MVPA). Thus, the purpose of this review was to update our existing knowledge of "How many steps/day are enough?", and to inform step-based recommendations consistent with current physical activity guidelines. Normative data indicate that healthy adults typically take between 4,000 and 18,000 steps/day, and that 10,000 steps/day is reasonable for this population, although there are notable "low active populations." Interventions demonstrate incremental increases on the order of 2,000-2,500 steps/day. The results of seven different controlled studies demonstrate that there is a strong relationship between cadence and intensity. Further, despite some inter-individual variation, 100 steps/minute represents a reasonable floor value indicative of moderate intensity walking. Multiplying this cadence by 30 minutes (i.e., typical of a daily recommendation) produces a minimum of 3,000 steps that is best used as a heuristic (i.e., guiding) value, but these steps must be taken over and above habitual activity levels to be a true expression of free-living steps/day that also includes recommendations for minimal amounts of time in MVPA. Computed steps/day translations of time in MVPA that also include estimates of habitual activity levels equate to 7,100 to 11,000 steps/day. A direct estimate of minimal amounts of MVPA accumulated in the course of objectively monitored free-living behaviour is 7,000-8,000 steps/day. A scale that spans a wide range of incremental increases in steps/day and is congruent with public health recognition that "some physical activity is better than none," yet still incorporates step-based translations of recommended amounts of time in MVPA may be useful in research and practice. The full range of users (researchers to practitioners to the general public) of objective monitoring instruments that provide step-based outputs require good reference data and evidence-based recommendations to be able to design effective health messages congruent with public health physical activity guidelines, guide behaviour change, and ultimately measure, track, and interpret steps/day.

How many steps/day are enough? For older adults and special populations.

Older adults and special populations (living with disability and/or chronic illness that may limit mobility and/or physical endurance) can benefit from practicing a more physically active lifestyle, typically by increasing ambulatory activity. Step counting devices (accelerometers and pedometers) offer an opportunity to monitor daily ambulatory activity; however, an appropriate translation of public health guidelines in terms of steps/day is unknown. Therefore this review was conducted to translate public health recommendations in terms of steps/day. Normative data indicates that 1) healthy older adults average 2,000-9,000 steps/day, and 2) special populations average 1,200-8,800 steps/day. Pedometer-based interventions in older adults and special populations elicit a weighted increase of approximately 775 steps/day (or an effect size of 0.26) and 2,215 steps/day (or an effect size of 0.67), respectively. There is no evidence to inform a moderate intensity cadence (i.e., steps/minute) in older adults at this time. However, using the adult cadence of 100 steps/minute to demark the lower end of an absolutely-defined moderate intensity (i.e., 3 METs), and multiplying this by 30 minutes produces a reasonable heuristic (i.e., guiding) value of 3,000 steps. However, this cadence may be unattainable in some frail/diseased populations. Regardless, to truly translate public health guidelines, these steps should be taken over and above activities performed in the course of daily living, be of at least moderate intensity accumulated in minimally 10 minute bouts, and add up to at least 150 minutes over the week. Considering a daily background of 5,000 steps/day (which may actually be too high for some older adults and/or special populations), a computed translation approximates 8,000 steps on days that include a target of achieving 30 minutes of moderate-to-vigorous physical activity (MVPA), and approximately 7,100 steps/day if averaged over a week. Measured directly and including these background activities, the evidence suggests that 30 minutes of daily MVPA accumulated in addition to habitual daily activities in healthy older adults is equivalent to taking approximately 7,000-10,000 steps/day. Those living with disability and/or chronic illness (that limits mobility and or/physical endurance) display lower levels of background daily activity, and this will affect whole-day estimates of recommended physical activity.

Reliability of the parallel walk test for the elderly.

OBJECTIVE: To determine interrater agreement and test-retest reliability of the parallel walk test (PWT), a simple method of measuring dynamic balance in the elderly during gait. DESIGN: Cohort study. SETTING: Outpatient clinic. PARTICIPANTS: Elderly fallers (N=34; mean ± SD age, 81.3±5.4y) registered at a falls clinic participated in this study based on Mini-Mental State Examination and Barthel Index scores. INTERVENTIONS: Subjects were timed as they walked 6m between 2 parallel lines on the floor at 3 different widths (20, 30.5, 38cm) wearing their own footwear. They were scored for foot placement on (1 point) or outside the lines (2 points) by 2 separate raters. Fifteen subjects were retested 1 week later. MAIN OUTCOME MEASURES: Footfall score and time to complete the PWT. Intraclass correlation coefficients (ICCs) and 95% limits of agreement were calculated for interrater and test-retest reliability. RESULTS: For widths of 20, 30.5, and 38cm, interrater reliability ICC range was .93 to .99 and test-retest ICC range was .63 to .90. CONCLUSIONS: The PWT was implemented easily by 2 raters with a high degree of interrater reliability. Test-retest reliability was not as high, possibly because of the high susceptibility of variation from 1 week to the next for frail elderly subjects. The 20- and 30.5-cm widths are recommended for future use of the PWT.

The Strathclyde Evaluation of Children's Active Travel (SE-CAT): study rationale and methods.

BACKGROUND: The school commute is a prime opportunity to increase children's physical activity levels. However, active commuting has decreased over the past 40 years. Strategies that increase walking to school are therefore needed. Travelling Green (TG) is a school-based active travel resource aimed at increasing children's walking to school. The resource consists of a curriculum-based program of lessons and goal setting activities. A previous study found that children who received the TG intervention increased self-reported distance travelled to school by active modes and reduced the distance travelled by inactive modes. This study was limited by self-reported outcome measures, a small sample, and no follow-up measures. A more robust evaluation of TG is required to address these limitations. This paper describes the rationale and methods for such an evaluation of Travelling Green, and describes the piloting of various active commuting measures in primary school children. METHODS/DESIGN: Measures of active commuting were piloted in a sample of 26 children (aged 8-9 years) over one school week. These measures were subsequently used in an 18-month quasi-experimental design to evaluate the effect of TG on commuting behaviour. Participants were 166 children (60% male) aged 8-9 years from 5 primary schools. Two schools (n = 79 children) received TG in September/October 2009. Three schools (n = 87 children) acted as a comparison group, and subsequently received TG at a later date. Physical activity was measured using Actigraph GT1M accelerometers. Personal and environmental determinants of active commuting were measured via parent and child questionnaires, as were factors related to the Theory of Planned Behaviour and the construct of habit. Measures were taken pre- and post-intervention and at 5 and 12 months follow-up. DISCUSSION: The piloted protocol was practical and feasible and piloted measures were reliable and valid. All study data, including 5 and 12 month follow-up, have been collected and processed. Data analysis is ongoing. Results will indicate whether TG successfully increases active commuting in a sample of Scottish school children and will inform future efforts in school active travel promotion.

West End Walkers 65+: a randomised controlled trial of a primary care-based walking intervention for older adults: study rationale and design.

BACKGROUND: In Scotland, older adults are a key target group for physical activity intervention due to the large proportion who are inactive. The health benefits of an active lifestyle are well established but more research is required on the most effective interventions to increase activity in older adults. The 'West End Walkers 65+' randomised controlled trial aims to examine the feasibility of delivering a pedometer-based walking intervention to adults aged 65 years through a primary care setting and to determine the efficacy of this pilot. The study rationale, protocol and recruitment process are discussed in this paper. METHODS/DESIGN: The intervention consisted of a 12-week pedometer-based graduated walking programme and physical activity consultations. Participants were randomised into an immediate intervention group (immediate group) or a 12-week waiting list control group (delayed group) who then received the intervention. For the pilot element of this study, the primary outcome measure was pedometer step counts. Secondary outcome measures of sedentary time and physical activity (time spent lying/sitting, standing or walking; activPAL™ monitor), mood (Positive and Negative Affect Schedule), functional ability (Perceived Motor-Efficacy Scale for Older Adults), quality of life (Short-Form (36) Health Survey version 2) and loneliness (UCLA Loneliness Scale) were assessed. Focus groups with participants and semi-structured interviews with the research team captured their experiences of the intervention. The feasibility component of this trial examined recruitment via primary care and retention of participants, appropriateness of the intervention for older adults and the delivery of the intervention by a practice nurse. DISCUSSION: West End Walkers 65+ will determine the feasibility and pilot the efficacy of delivering a pedometer-based walking intervention through primary care to Scottish adults aged 65 years. The study will also examine the effect of the intervention on the well-being of participants and gain an insight into both participant and research team member experiences of the intervention.

Exercise and Protein Effects on Strength and Function with Weight Loss in Older Women.

Obesity negatively affects lower extremity physical function (LEPF) in older adults. Exercise and a higher protein diet are both known to positively and independently affect body composition, muscle strength, and LEPF during weight loss; however, their potential interactive effects have not been well characterized in older women. PURPOSE: The aim of this study was to determine the relative efficacy of a higher protein diet with or without exercise to improve body composition, muscle strength, and LEPF in older inactive overweight/obese women after weight loss. METHODS: Postmenopausal women (body mass index = 31.1 ± 5.1 kg·m, 69.2 ± 3.6 yr) completed a 6-month weight loss program after randomization to three groups (n = 72 randomized; 15% dropout): 1) higher protein diet (PRO, ~30% energy from protein; n = 20), 2) PRO plus exercise (PRO + EX; n = 19), or 3) a conventional protein control diet plus EX (CON + EX, ~18% energy from protein; n = 22). EX was supervised, multicomponent (aerobic, muscle strengthening, balance, and flexibility), and three sessions per week. Body composition was measured via dual-energy x-ray absorptiometry, leg strength by isokinetic dynamometry, and LEPF via 6-min walk, 8-ft up and go, and 30-s chair stand tests. RESULTS: Changes in weight (-7.5 ± 4.1 kg; -9.2% ± 4.8%), fat mass, and leg lean mass did not differ among groups (all P > 0.50). Despite weight loss, muscle strength improved in the exercise groups (PRO + EX and CON + EX) but it declined in the PRO group (P = 0.008). For all LEPF measures, the PRO group had attenuated improvements compared with both PRO + EX and CON + EX (all P < 0.01). CONCLUSION: Exercise during weight loss is critical to preserve strength and enhance LEPF; however, a higher protein diet does not appear to influence body composition, muscle strength, or LEPF changes when combined with multicomponent exercise.

A DXA-based mathematical model predicts midthigh muscle mass from magnetic resonance imaging in typically developing children but not in those with quadriplegic cerebral palsy.

Valid methods for assessing regional muscle mass in children are needed. The aim of this study was to determine whether dual-energy X-ray absorptiometry (DXA) can accurately estimate midthigh muscle mass from MRI (muscle(MRI)) in typically developing children and children with quadriplegic cerebral palsy (CP). A mathematical model predicting muscle(MRI) from midthigh, fat-free soft tissue mass from DXA (FFST(DXA)) was developed using 48 typically developing children (6-13 y) and was validated using the leave-one-out method. The model was also tested in children with quadriplegic CP (n = 10). The model produced valid estimates of midthigh muscle mass (muscle(DXA)) in typically developing children, as indicated by a very strong relationship between muscle(DXA) and muscle(MRI) (r(2) = 0.95; SEE = 68 g; P < 0.001), no difference in muscle(DXA) and muscle(MRI) (P = 0.951), and visual examination using a Bland-Altman plot. Muscle(DXA) was very strongly related to muscle(MRI) in children with CP (r(2) = 0.96; SEE = 54 g; P < 0.001); however, muscle(DXA) overestimated muscle(MRI) by 15% (P = 0.006). The overestimation of muscle(MRI) by muscle(DXA) was strongly related to the lower ratio of muscle(MRI) to FFST(DXA) (muscle(MRI)/FFST(DXA)) in children with CP (r(2) = 0.75; P = 0.001). The findings suggest that the DXA-based mathematical model developed in the current study can accurately estimate midthigh muscle mass in typically developing children. However, a population-specific model that takes into account the lower muscle(MRI)/FFST(DXA) is needed to estimate midthigh muscle mass in children with quadriplegic CP.

Walking and measurement.

Walking is an important form of physical activity. It is practiced by people of nearly all ages, throughout the world. Walking is an integral part of life, and there is accumulating evidence that it is essential to good health. There are many ways to measure walking including pedometers, accelerometers, trail counters, direct observation, physical activity questionnaires, and transportation surveys. When measuring walking, researchers must be prepared to demonstrate the validity of their instruments. A paradigm for validation in walking research consists of accumulating evidence at three levels or stages. First, the definitional stage involves investigation of prior theory and empirical evidence to describe the nature of walking. The confirmatory stage involves investigations that either confirm or disconfirm the definition of walking. The highest level of validation is at the theory-testing stage, where we examine theories of how walking is related to other constructs, including the outcomes and the determinants of walking. It is important that validation research in the latter two stages (confirmatory research and theory-testing research) is built on directly relevant research at the earlier stages. The articles presented at the conference on "Walking for Health: Measurement and Research Issues and Challenges" suggest future research directions that will increase our knowledge of walking and health outcomes and provide new approaches to get people walking.

Classroom-Based Physical Activity and Sedentary Behavior Interventions in Adolescents: A Systematic Review and Meta-Analysis.

BACKGROUND: It is reported that 81% of adolescents are insufficiently active. Schools play a pivotal role in promoting physical activity (PA) and reducing sedentary behavior (SB). The aim of this systematic review and meta-analysis was to evaluate classroom-based PA and SB interventions in adolescents. METHODS: A search strategy was developed using the Population Intervention Comparison Outcome Study (PICOS) design framework. Articles were screened using strict inclusion criteria. Study quality was assessed using the Effective Public Health Practice Project quality assessment tool ( http://www.ephpp.ca/tools.html ). Outcome data for preintervention and postintervention were extracted, and effect sizes were calculated using Cohen's d. RESULTS: The strategy yielded 7574 potentially relevant articles. Nine studies were included for review. Study quality was rated as strong for 1 study, moderate for 5 studies, and weak for 3 studies. Five studies were included for meta-analyses, which suggested that the classroom-based interventions had a nonsignificant effect on PA (P = .55, d = 0.05) and a small, nonsignificant effect on SB (P = .16, d = -0.11). CONCLUSION: Only 9 relevant studies were found, and the effectiveness of the classroom-based PA and SB interventions varied. Based on limited empirical studies, there is not enough evidence to determine the most effective classroom-based methodology to increase PA and SB.