Comparing physical activity estimates in children from hip-worn Actigraph GT3X+ accelerometers using raw and counts based processing methods

This study examined differences in physical activity (PA) estimates provided from raw and counts processing methods. One hundred and sixty-five children (87 girls) wore a hip-mounted ActiGraph GT3X+ accelerometer for 7 days. Data were available for 129 participants. Time in moderate PA (MPA), vigorous PA (VPA) and moderate-vigorous PA (MVPA) were calculated using R-package GGIR and ActiLife. Participants meeting the wear time criteria for both processing methods were included in the analysis. Time spent in MPA (?21.4 min.d^?1, 95%CI ?21 to ?20) and VPA (?36 min.d^?1, 95%CI ?40 to ?33) from count data were higher (P < 0.001) than raw data. Time spent in MVPA between the two processing methods revealed significant differences (All P < 0.001). Bland-Altman plots suggest that the mean bias for time spent in MPA, VPA and MVPA were large when comparing raw and count methods. Equivalence tests showed that estimates from raw and count processing methods across all activity intensities lacked equivalence. Lack of equivalence and poor agreement between raw and count processing methods suggest the two approaches to estimate PA are not comparable. Further work to facilitate the comparison of findings between studies that process and report raw and count physical activity data may be necessary.     

Comparability of accelerometer- and IPAQ-derived physical activity and sedentary time in South Asian women: A cross-sectional study

Abstract

There is limited research documenting objectively measured physical activity (PA) and sedentary time (ST) in South Asian (SA) women, with no published evidence of the validity of self-report methods for assessment of PA/ST in SA. The purpose of this study was to compare accelerometer- and International Physical Activity Questionnaire (IPAQ)-derived PA/ST among SA women in the United Kingdom (UK) via a mixed-methods approach. One hundred and forty SA women wore an accelerometer for seven consecutive days; a sub-sample (n = 50) completed the IPAQ-Short Form (IPAQ-SF) and a brief structured interview. Accelerometer-derived metabolic equivalent (MET) minutes per week (min/wk) moderate-to-vigorous physical activity (MVPA) (mean ± SD) for the full sample was 793.94 (±519.44) and mean accelerometer-derived ST wk was 530.20 (±81.76). IPAQ-SF-derived MVPA (MET min/wk) was 636.80 (±2113.56) and mean ST wk was 315.31 (±266.98). Pearson correlations were not significant between accelerometer- and IPAQ-SF-assessed MVPA (r = ?.119, p = .579) and ST (r = ?.140, p = .229). Major themes synthesised from interviews included inability to recall sitting time and limited general knowledge of real-life examples of MVPA. These results suggest that the IPAQ-SF may not accurately measure PA/ST in the UK SA women. These findings are supported by qualitative evidence indicating several issues with interpretation and recall of PA/ST as assessed via this questionnaire.     

Domain-specific physical activity and health-related quality of life in university students

Abstract

Information on the relationship between domain-specific physical activity (PA) and health-related quality of life (HRQoL) in the general population and specific groups is still scarce. The aim of this study was to determine the relationship between PA in work, transport, domestic and leisure-time domains and HRQoL among university students. PA and HRQoL were assessed in a random stratified sample of 1750 university students using the International Physical Activity Questionnaire – long form and 12-item Short Form Health Survey, respectively. The Spearman's rank correlations, adjusted for age, community size, personal monthly budget, body mass index, smoking habits and alcohol intake ranged from ?0.11 to 0.18 in female students and ?0.29 to 0.19 in male students. Leisure-time, domestic, transport-related PA and total PA were positively related to HRQoL. Inverse correlations with HRQoL were only found for work-related PA in male students. Multiple linear regression analysis showed that only leisure-time PA was related to the Physical Summary Component score (β = 0.08 for females and β = 0.10 for males, P < 0.05). Domain-specific PA levels were not significantly related to the Mental Component Summary score. To get a more comprehensive insight in the relationship between PA and HRQoL, future studies should not only analyse total PA levels but also domain-specific PA levels. The evidence on the positive relationship of leisure-time, transport and domestic PA with HRQoL can potentially be used to support evidence-based promotion of PA in a university setting, and as a hypothesis for future longitudinal studies on such potential causal relationships.     

Moderate and vigorous physical activity intensity cut-points for the Actical accelerometer

Abstract

Accelerometry is increasingly used as a physical activity surveillance device that can quantify the amount of time spent moving at a range of intensities. This study proposes physical activity intensity cut-points for the Actical accelerometer. Thirty-eight volunteers completed a multi-stage treadmill protocol at 3, 5, and 8 km · h^?1 (2, 3.3, and 8 METs) while wearing Actical accelerometers initialized to collect data in 60-s epochs. Using a decision boundary analytical approach, moderate and vigorous physical activity intensity cut-points were derived for the Actical accelerometer. In adults (n = 26), the cut-point for moderate physical activity intensity occurred at 1535 counts per minute and the vigorous cut-point occurred at 3960 counts per minute. In children (n = 12), the cut-point for moderate physical activity intensity occurred at 1600 counts per minute and the vigorous cut-point occurred at 4760 counts per minute. Improved classification of physical activity intensity using the decision boundary cut-points was observed compared with using mean values for each protocol stage. The cut-points derived are recommended for use in adults. The cut-points derived for children confirm the findings of previous studies.     

The effect of pedometer use on physical activity and body weight in obese women

Abstract

Physical activity and healthy eating are of the utmost importance in treatment of obesity. However obese generally tend to have a sedentary lifestyle. Walking is a form of physical activity that is both simple and can be performed by everyone, but it requires an objective measurement. Number of steps taken during tracking can be recorded with the pedometer, a device used to measure the level of physical activity. We aimed to investigate whether or not using pedometers as a motivational technique to increase the level of physical activity in obese women has an impact on weight loss. Eighty-four obese women who are similar age referring to Ataturk University Faculty of Medicine Healthy Living Clinic, Turkey were randomly divided into two groups. Intervention group were given pedometers, and control group were prescribed similar diet and physical activity with a three-month follow-up plan without pedometers. Mean weight in pedometer group initially was 88.9 ± 8.4 kg, which decreased to 80.2 ± 8.7 kg after the programme. Mean weight in control group was 86.1 ± 9.2 kg at the beginning, and it decreased to 84.7 ± 8.8 kg after three months. It was observed in pedometer group that the mean number of steps 8817 ± 2725 steps/day at the beginning increased to mean 9716 ± 2811 steps/day at the end of the study. Weight, body mass index, body fat percentage and waist circumference measurements decreased more greatly in the pedometer when compared to the control group (p < 0.001). Pedometers may be recommended to obese patients to monitor and increase the level of physical activity and to promote weight loss.     

Self-rated wellbeing and physical activity associations in European older adults

Background: Physical activity and self-rated wellbeing have important benefits to health. However, scientific knowledge regarding their relationship among older adults is scarce. Thus, the aim of this study was to examine the associations between physical activity frequency and several dimensions of self-rated wellbeing, in a representative sample of European older adults from 28 countries. Methods: This study is based on the European Social Survey round 6, 2012. It had a total sample size of 12,341 older adults (5100 men, 7241 women) with mean age 73.8?±?6.6 years. Information was collected through a questionnaire, filled-in during an hour-long face-to-face interview. Physical activity was accessed using the question “On how many of the last 7 days you were physically active continuously for 20 minutes or longer?” and six dimensions of self-rated wellbeing were used. Results: Physical activity in the last 7 days was linearly related with all dimension of the self-rated wellbeing and with wellbeing total score for both sexes (men, β?=?0.09, 95% CI: 0.07 to 0.10, p?β?=?0.10, 95% CI: 0.09 to 0.11, p?Conclusions: Physical activity promotion should be stressed as a meaningful strategy to improve people's wellbeing overall. This strategy has special importance when considering the older adult population.     

Reliability of pedometer-determined free-living physical activity data in college women

This study examined stability and reliability of free-living physical activity assessed by pedometer in 69 young female college students (M age = 18.7 years, SD = 1.2, range: 18-25 years; body mass index = 23.2 kg/m2, SD = 0.6) for two complete weeks (Week 1 and Week 2) separated by 12 weeks. During Week 1, participants took an average of 8880 steps/day, SD = 3219, range: 1858-19480; during Week 2 9088 steps/day, SD = 3299, range 1736-16837; t (68) = -.568, p = .572. In both weeks, only Sunday differed significantly (repeated measures analysis of variance; Week 1: p < .0001; Week 2: p < .01) from all other days of the week. The computed intraclass correlation between weeks was moderate (.72). Group mean pedometer-determined physical activity was stable across 2 weeks separated by 12 weeks in this young, healthy sample of women. Individuals within these groups held their rank order to a moderate extent over time. These findings provide important evidence of the reliability of pedometer-determined physical activity data and are of practical importance to study design.     

Effect of a randomised 12-week resistance training programme on muscular strength,cross-sectional area and muscle quality in women having undergone Roux-en-Y gastric bypass

The purpose of this study was to examine the effect of a 12-week resistance training programme on fat-free mass (FFM), muscle cross-sectional area, muscular strength and muscle quality in women who underwent Roux-en-Y gastric bypass surgery. Participants were 16 women (mean age = 44.9 ± 10.2 years) from bariatric surgical groups who were randomly assigned into either a control or an intervention group. Air displacement plethysmography measured FFM and magnetic resonance imaging measured quadriceps muscle cross-sectional area and whole thigh muscle cross-sectional area. Muscular strength and quality was assessed using an estimated 1-Repetition Maximum assessment. All measurements were collected twice, at baseline and at a 12-week follow-up. There were significantly greater improvements in leg press strength (mean differences = 55.4%, P < 0.001, Cohen’s d = 2.4), leg extension strength (mean differences = 18.0%, P = 0.014, Cohen’s d = 0.86) and leg press muscle quality (mean differences = 54.5%, P < 0.001, Cohen’s d = 1.9) in the intervention group compared to the control group following the resistance training programme. The resistance training intervention significantly improved muscular strength and quality; however, it did not illicit changes in FFM or muscle cross-sectional area in women who underwent Roux-en-Y gastric bypass surgery.     

Caution using data from triaxial accelerometers housed in player tracking units during running

Usage of accelerometers within player tracking devices in sport to quantify load, vertical ground reaction force (vGRF) or energy expenditure is contrary to placement guidelines. This study aimed to determine whether trunk-mounted accelerometers were a valid and reliable method to estimate thoracic segment or centre of gravity (COG) acceleration or vGRF, and the whether the elasticised harness contributes to the overestimation of acceleration. Ten male amateur rugby players performed five linear running tasks per lower limb at three speeds, twice, each with a different player tracking unit. Three-dimensional data were recorded and triaxial accelerometers were attached lateral to the device on the harness and skin and both shanks. Accelerometers demonstrated poor reliability (ICC:0.0–0.67), high variability (CV%:14–33%) and change in mean (41–160%), and were not valid to estimate vertical acceleration of the COG and thoracic segment nor vGRF. Caution is advised when utilising trunk-mounted triaxial accelerometer data as it is not a valid or reliable means to estimate peak vertical acceleration for its thoracic location nor whole-body COG acceleration or vGRF during running. To improve player tracking instrument validity and reliability, a new attachment method and/or harness material(s), that reduce or eliminate extraneous acceleration during running, are urgently required.     

Validation of a one-day self-report questionnaire for physical activity assessment in healthy adults

Abstract

A self-report physical activity scale (PAS) has previously been developed to document physical activity (MET-hours) undertaken by adults during an average weekday. The current study aimed to validate the PAS over 24 hours via pedometer determinations of physical activity in healthy, active adults, and to determine possible influences of gender and body mass status on this relationship. One-hundred and seven healthy university students (age 18–41 years) wore a pedometer (Yamax DigiWalker SW-700) during the waking hours of an average weekday followed by successful completion of the PAS. Relationships between the PAS and pedometer measures (steps taken and energy expenditure) were examined by Pearson's correlation coefficients. Significant (P<0.05) gender and body mass status differences were examined by two-way analysis of variance with Tukey post-hoc tests. Participants reported 48.0±10.4 MET-hours of activity, completed 11,506±4195 steps, and expended 499±227 kcal during an average weekday. Physical activity measures, except energy expenditure, were similar across groups by gender and body mass status. The total number of MET-hours was significantly associated with pedometer steps taken (r=0.375–0.568, P<0.01), and this relationship varied by gender and to a lesser extent by body mass status. The results of the current study show that the self-reported physical activity of healthy active adults was in line with the popular recommended dose of daily physical activity (10,000 steps per day) and was not influenced by gender or body mass status. Furthermore, over an average weekday, the PAS provided a simple, quick, and valid method to document physical activity undertaken by young healthy active adults that is comparable to pedometer readings.     

Evaluation of an unstructured afterschool physical activity programme for disadvantaged youth

The purpose of the study was to conduct an evaluation of an unstructured afterschool physical activity (PA) programme (Keep it Moving!; KIM) in an ethnically diverse and low socio-economic status (SES) school district. PA of students in 3rd–5th grades (N = 205) at four elementary schools were assessed during spring 2012. An ActiGraph accelerometer was utilised to examine objectively measured time and steps in differing intensity levels. Standard data reduction procedures were used to process collected data and characterise PA. Students averaged approximately 54 min of accelerometer wear-time during the KIM programme, 10.4 ± 6.1 min (19.2%) of which were spent in sedentary behaviour, 28.2 ± 8.3 min (52.1%) in light PA and 15.6 ± 6.6 min (28.7%) in moderate-to-vigorous intensity PA. Within the cadence band of 1–19 steps/min participants accumulated the highest time-derived PA (16.4 ± 6.3 min). In total, children averaged 1811.9 ± 527.5 steps during the entire KIM programme. Results from the programme indicated that elementary-aged students received additional PA through the KIM programme. The mean value of accumulated steps during the afterschool PA programme represented 12–16.5% of the minimum steps/day target (depending upon gender) identified for elementary-aged school children. These data represent unique findings from a high-need population that may be helpful for researchers and practitioners alike.     

Measures of cardiac autonomic control in women with differing volumes of physical activity

Abstract

The most recent (1996) drinking guidelines of the American College of Sports Medicine (ACSM) propose that athletes should drink “as much as tolerable” during exercise. Since some individuals can tolerate rates of free water ingestion that exceed their rates of free water loss during exercise, this advice has caused some to overdrink leading to water retention, weight gain and, in a few, death from exercise-associated hyponatraemic encephalopathy. The new drinking guidelines of the International Olympic Committee (IOC), recently re-published in this Journal, continue to argue that athletes must drink enough to replace all their weight lost during exercise and to ingest sodium chloride since sodium is “the electrolyte most critical to performance and health”. In this rebuttal to that Consensus Document, I argue that these new guidelines, like their predecessors, lack an adequate, scientifically proven evidence base. Nor have they been properly evaluated in appropriately controlled, randomized, prospective clinical trials. In particular, these new guidelines provide erroneous recommendations on five topics.

If novel universal guidelines for fluid ingestion during exercise are to be promulgated by important international bodies including the IOC, they should first be properly evaluated in appropriately controlled, randomized, prospective clinical trials conducted under environmental and other conditions that match those found in “out-of-doors” exercise. This, and the potential influence of commercial interests on scientific independence and objectivity, are the two most important lessons to be learned from the premature adoption of those 1996 ACSM drinking guidelines that are not evidence-based. These concerns need to be addressed before the novel IOC guidelines are accepted uncritically. Otherwise the predictable consequences of the premature adoption of the 1996 ACSM guidelines will be repeated.     

Social physique anxiety and physical activity behaviour of male and female exercisers

Despite females consistently reporting greater social physique anxiety (SPA), previous literature has yet to demonstrate whether SPA gender differences are linked to the way males and females perform physical activity. This study investigated an association between SPA and physical activity frequency, history of exercise, and physical activity intensity. Participants were represented by currently active users (N?=?33 males; N?=?31 females) of an on-campus university-run gym and completed a background physical activity questionnaire and the nine-item Social Physique Anxiety Scale. Participants also performed an exercise session at a self-selected level of exertion, with the intensity of each session measured via heart rate monitor. SPA was not associated with physical activity frequency, history of exercise (length of gym membership), or intensity for male and female exercisers. With respect to male participants, females reported higher SPA and a preference for performing higher intensity physical activity. Females and males also indicated a preference for performing aerobic and anaerobic physical activity respectively. Our findings suggest the experience of SPA does not deter body-conscious individuals from the performance of regular physical activity. Findings also suggest the discrepancy in male and female SPA is not linked to differences in the way physical activity is performed.     

济南市老年人健身状况调查

通过调查，了解到济南市82.6％的家庭里有老年人外出锻炼。1998年济南市老年人寿命已达到72.4岁，但带病期长，生活质量不高，高血压、脑血管疾病、冠心病明显增加。多数人没有养成良好的锻炼习惯，未能广泛地吸取健身知识、总结适合自己的锻炼方法。影响济南市老年人健身的还有一些外部因素，如资金不足、锻炼场所少以及健身辅导员缺乏等。改善济南市老年人的健身状况，政府和社会各方面要共同努力，不断提高老年人自身的健身意识。     

Health-enhancing physical activity and sedentary behaviour in children and adolescents

We provide a wide-ranging review of health-related physical activity in children and adolescents using a behavioural epidemiology framework. In contrast to many other reviews, we highlight issues associated with true sedentary behaviours alongside physically active behaviours. Specifically, we review the evidence concerning the links between physical activity and cardiovascular disease, overweight and obesity, psychosocial measures, type II diabetes, and skeletal health. Although the evidence is unconvincing at times, several factors lead to the conclusion that promoting physical activity in youth is desirable. A review of the prevalence of physical activity and sedentary behaviours shows that many young people are active, but this declines with age. A substantial number are not adequately active for health benefits and current trends in juvenile obesity are a cause for concern. Prevalence data on sedentary behaviours are less extensive but suggest that total media use by young people has not changed greatly in recent years. Most children and adolescents do not exceed recommended daily hours of TV viewing. Physical activity is unrelated to TV viewing. We also identified the key determinants of physical activity in this age group, highlighting demographic, biological, psychological, behavioural, social and environmental determinants. Interventions were considered for school, family and community environments. Finally, policy recommendations are offered for the education, governmental, sport and recreation, health, and mass media sectors.     

Evidence for data missing at random in youth physical activity monitoring research

This study examined whether or not activity monitor data collected as part of a typical 7-day physical activity (PA) measurement protocol can be expected to be missing at random. A total of 315 participants (9–18 years) each wore a SenseWear Armband monitor for 7 consecutive days. Participants were classified as “compliant” (86 boys and 124 girls) if they had recorded accelerometer data during 70% or more of the predefined awake time (7 AM–10 PM) on four different days; and “non-compliant” (44 boys and 51 girls) when not meeting these criteria. Linear mixed models were used to examine differences in energy expenditure (EE) levels by compliance across 10 different time periods. The results indicated that non-compliant girls were older (13.4 ± 2.9 vs. 12.2 ± 2.5) and taller (156.8 ± 10.3 vs. 152.8 ± 11.3) than their same gender compliant peers (P < .05). Comparisons of EE rates at segmented portions of the day revealed no differences between compliant and non-compliant groups (P ≥ .05). Differences in EE ranged from ?0.32 kcal · kg^?1 · h^?1 (before school time) to 0.62 kcal · kg^?1 · h^?1 (physical education class) in boys and ?0.39 kcal · kg^?1 · h^?1 (transportation from school) to 0.37 kcal · kg^?1 · hour^?1 (recess) in girls. The results showed that compliant and non-compliant individuals differed in a few demographic characteristics but exhibited similar activity patterns. This suggests that data were considered to be missing at random, but additional work is needed to confirm this observation in a representative sample of children using other types of activity monitors and protocols.     

Development of raw acceleration cut-points for wrist and hip accelerometers to assess sedentary behaviour and physical activity in 5–7-year-old children

ABSTRACT

This study validated sedentary behaviour (SB), moderate-to-vigorous physical activity (MVPA) and vigorous physical activity (VPA) accelerometer cut-points in 5–7-year-old children. Participants (n = 49, 55% girls) wore an ActiGraph GT9X accelerometer, recording data at 100 Hz downloaded in 1 s epochs, on both wrists and the right hip during a standardised protocol and recess. Cut-points were generated using ROC analysis with direct observation as a criterion. Subsequently, cut-points were optimised using Confidence intervals equivalency analysis and then cross-validated in a cross-validation group. SB cut-points were 36 mg (Sensitivity (Sn) = 79.8%, Specificity (Sp) = 56.8%) for non-dominant wrist, 39 mg (Sn = 75.4%, Sp = 70.2%) for dominant wrist and 20 mg (Sn = 78%, Sp = 50.1%) for hip. MVPA cut-points were 189 mg (Sn = 82.6%, Sp = 78%) for non-dominant wrist, 181 mg (Sn = 79.1%, Sp = 76%) for dominant wrist and 95 mg (Sn = 79.3%, Sp = 75.6%) for hip. VPA cut-points were 536 mg (Sn = 75.1%, Sp = 68.7%) for non-dominant wrist, 534 mg (Sn = 67.6%, Sp = 95.6%) for dominant wrist and 325 mg (Sn = 78.2%, Sp = 96.1%) for hip. All placements demonstrated adequate levels of accuracy for SB and PA assessment.     

Centralising space: the physical education and physical activity experiences of South Asian,Muslim girls

This paper explores the physical education (PE) and physical activity experiences of a group of South Asian, Muslim girls, a group typically marginalised in PE and physical activity research. The study responds to ongoing calls for research to explore across different spaces in young people's lives. Specifically, I draw on a ‘middle-ground’ approach, using Hill Collins' matrix of domination and the notion of intersectionality. These concepts offer the possibility to explore the kinds of settings (physical, social and cultural) in which girls undertake PE and physical activity, how these spaces influence experience and how the girls navigate these spaces. The study is based in a large, urban, co-educational, secondary school in Yorkshire, England (95% of the students are from minority ethnic communities, 91% are Muslim and 63% live in the top 10% most deprived neighbourhoods in the country). Data generation involved three phases: observations, creating research artefacts in focus groups and in-depth interviews. The findings reveal the diverse ways the girls are physically active. They also demonstrate a complexity to their involvement which is contingent upon space, discourses and people. For example, discourses of competition, ability and peers are more significant within PE; whilst family, religion and culture feature beyond this context. The paper concludes by acknowledging the girls' heterogeneity and agency in the ways they strategically navigate spaces in their quest to be physically active on their terms.     

有氧运动对肥胖妇女血清瘦素、脂联素的影响

目的:研究12周有氧训练对肥胖妇女血清瘦素、脂联素水平的影响,及它们与体成分和脂代谢的关系.方法:对15名肥胖妇女(年龄为38.3±5.6岁,BMI为28.36±1.73)进行12周有氧训练干预,并于实验前测试体成分、血脂、瘦素和脂联素等指标.结果:12周有氧训练后,受试者的体重、BMI、体脂百分比、甘油三酯、游离脂肪酸和血清瘦素水平有了显著性的下降;血清脂联素水平有了显著性的上升.血清瘦素的变化量与体脂百分比的变化量相关.血清脂联素的变化量与体重的变化量相关.结论:12周有氧训练有效地改善了肥胖妇女的体成分和血脂水平;促进了血清瘦素和脂联素的良性变化;血清瘦素和脂联素的变化与体重的变化密切相关.     

健康体适能教学的实验观察

为进一步评估健康体适能的教学效果 ,观察了特定运动处方对受试者心脏功能 (FC)、肌肉力量(ST)和柔软度 (FL)的影响。实验前根据FC、ST和FL的检测结果 ,将 2 4 0名男女医学生随机分成 3个对照组和 3个实验组。对照组按原教学进度上体育课 ,实验组以提高健康体适能为教学目标 ,以特定的运动处方进行教学和锻炼。结果显示 ,3个实验组FC、ST和FL指标明显增强 ,且有统计学意义 (P <0 .0 5 )。说明为健康体适能教学所制定的运动处方适用于普通院校大学生的体育教学 ,并可收到良好的效果。