Accelerometer data reduction: a comparison of four reduction algorithms on select outcome variables

Physical activity and metabolic health in chronic kidney disease: a cross-sectional study

Background

Patients with chronic kidney disease (CKD) are at high risk of progression to end stage renal disease and cardiovascular events. Physical activity may reduce these risks by improving metabolic health. We tested associations of physical activity with central components of metabolic health among people with moderate-severe non-diabetic CKD.

Methods

We performed a cross-sectional study of 47 people with CKD (estimated GFR <60 ml/min/1.73 m²) and 29 healthy control subjects. Accelerometry was used to measured physical activity over 7 days, the hyperinsulinemic-euglycemic clamp was used to measure insulin sensitivity, and DXA was used to measured fat mass. We tested associations of physical activity with insulin sensitivity, fat mass, blood pressure, serum lipid concentrations, and serum high sensitivity C-reactive protein concentration using multivariable linear regression, adjusting for possible confounding factors.

Results

Participants with CKD were less active than participants without CKD (mean (SD) 468.1 (233.1) versus 662.3 (292.5) counts per minute) and had lower insulin sensitivity (4.1 (2.1) versus 5.2 (2.0 (mg/min)/(μU/mL)), higher fat mass (32.0 (11.4) versus 29.4 (14.8) kg), and higher triglyceride concentrations (153.2 (91.6) versus 99.6 (66.8) mg/dL). With adjustment for demographics, comorbidity, medications, and estimated GFR, each two-fold higher level of physical activity was associated with a 0.9 (mg/min)/(μU/mL) higher insulin sensitivity (95% CI 0.2, 1.5, p = 0.006), an 8.0 kg lower fat mass (−12.9, −3.1, p = 0.001), and a 37.9 mg/dL lower triglyceride concentration (−71.9, −3.9, p = 0.03). Associations of physical activity with insulin sensitivity and triglycerides did not differ significantly by CKD status (p-values for interaction >0.3).

Conclusions

Greater physical activity is associated with multiple manifestations of metabolic health among people with moderate-severe CKD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0400-x) contains supplementary material, which is available to authorized users.

Frequency and duration of physical activity bouts in school-aged children: A comparison within and between days

Understanding how physical activity (PA) patterns vary within and between days may guide PA promotion in young people. We aimed to 1) describe and compare the frequency (bouts/day) and duration (min/bout) of bouts of moderate-to-vigorous intensity PA (MVPA) on weekdays vs. weekends and in-school vs. out-of-school, and 2) assess associations of bout frequency and duration in these time-segments with overall PA. We used cross-sectional accelerometer data from 2737 children (aged 6-19 years) in the United States National Health and Nutrition Examination Survey (NHANES) 2003-2006. A bout was defined as MVPA (≥ 2000 counts per minute [cpm]) lasting ≥ 3 min. Adjusted Wald tests were used to assess differences in bout characteristics between time-segments. Linear regression was used to examine the association of time-segment specific bout characteristics with daily minutes of MVPA and PA volume (average cpm). Bout frequency was higher on weekdays than weekends (median [IQR] 4.3 [2.2-7.2] vs. 3.0 [1.0-6.5] bouts/day, p < 0.001); however, bout duration did not differ (4.7 [4.0-5.7] vs. 4.5 [3.7-5.8] min/bout, p = 0.33). More bouts were accumulated out-of-school compared with in-school (2.2 [1.0-4.0] vs. 1.8 [0.8-3.2] bouts/day, p < 0.001), but bout duration was similar (4.7 [3.8-5.8] vs. 4.5 [3.8-5.7] min/bout, p = 0.158). For all time-segments, the frequency and duration of bouts of MVPA were independently and positively associated with overall MVPA and PA volume. In conclusion, the characteristics of children's PA vary within and between days; accounting for this in intervention design may improve future interventions. However, increasing bout frequency or duration in any time-segment may be beneficial for overall PA.

Lower rate-pressure product during submaximal walking: a link to fatigue improvement following a physical activity intervention among breast cancer survivors

PURPOSE

Research showing a link between exercise-induced changes in aerobic fitness and reduced fatigue after a cancer diagnosis has been inconsistent. We evaluated associations of fatigue and rate-pressure product (RPP), a reliable index of myocardial oxygen demand, at rest and during submaximal walking following a physical activity intervention among post-primary treatment breast cancer survivors (BCS).

METHODS

Secondary analyses of 152 BCS in a randomized controlled trial testing a physical activity intervention (INT) versus usual care (UC) were performed. The INT group completed counseling/group discussions along with supervised exercise sessions tapered to unsupervised exercise. Evaluations were made at baseline and immediately post-intervention (M3) on measures of physical activity (accelerometry), graded walk test, and average fatigue over the previous 7 days. RPP was calculated by dividing the product of heart rate and systolic blood pressure by 100.

RESULTS

Resting and submaximal RPPs were significantly improved in both groups at M3; however, the magnitude of change (∆) was greater in the INT group from stage 1 (∆RPP1; INT -13 ± 17 vs. UC -7 ± 18; p = 0.03) through stage 4 (∆RPP4; INT -21 ± 26 vs. UC -9 ± 24; p < 0.01) of the walk test. The INT group reported significantly reduced fatigue (INT -0.7 ± 2.0 vs. UC +0.1 ± 2.0; p = 0.02) which was positively associated with ∆RPP during stages 2-4 of the walk test but not ∆aerobic fitness.

CONCLUSIONS

Lower RPP during submaximal walking was significantly associated with reduced fatigue in BCS.

IMPLICATIONS FOR CANCER SURVIVORS

Exercise/physical activity training programs that lower the physiological strain during submaximal walking may produce the largest improvements in reported fatigue.

Effect of Wearable Technology Combined With a Lifestyle Intervention on Long-term Weight Loss: The IDEA Randomized Clinical Trial

IMPORTANCE

Effective long-term treatments are needed to address the obesity epidemic. Numerous wearable technologies specific to physical activity and diet are available, but it is unclear if these are effective at improving weight loss.

OBJECTIVE

To test the hypothesis that, compared with a standard behavioral weight loss intervention (standard intervention), a technology-enhanced weight loss intervention (enhanced intervention) would result in greater weight loss.

DESIGN, SETTING, PARTICIPANTS

Randomized clinical trial conducted at the University of Pittsburgh and enrolling 471 adult participants between October 2010 and October 2012, with data collection completed by December 2014.

INTERVENTIONS

Participants were placed on a low-calorie diet, prescribed increases in physical activity, and had group counseling sessions. At 6 months, the interventions added telephone counseling sessions, text message prompts, and access to study materials on a website. At 6 months, participants randomized to the standard intervention group initiated self-monitoring of diet and physical activity using a website, and those randomized to the enhanced intervention group were provided with a wearable device and accompanying web interface to monitor diet and physical activity.

MAIN OUTCOMES AND MEASURES

The primary outcome of weight was measured over 24 months at 6-month intervals, and the primary hypothesis tested the change in weight between 2 groups at 24 months. Secondary outcomes included body composition, fitness, physical activity, and dietary intake.

RESULTS

Among the 471 participants randomized (body mass index [BMI], 25 to <40; age range, 18-35 years; 28.9% nonwhite, 77.2% women), 470 (233 in the standard intervention group, 237 in the enhanced intervention group) initiated the interventions as randomized, and 74.5% completed the study. For the enhanced intervention group, mean base line weight was 96.3 kg (95% CI, 94.2-98.5) and 24-month weight 92.8 kg (95% CI, 90.6- 95.0) [corrected]. For the standard intervention group, mean baseline weight was 95.2kg (95%CI,93.0-97.3)and24-month weight was 89.3 kg (95%CI, 87.1-91.5) [corrected]. Weight change at 24 months differed significantly by intervention group (estimated mean weight loss, 3.5 kg [95% CI, 2.6-4.5} in the enhanced intervention group and 5.9 kg [95% CI, 5.0-6.8] in the standard intervention group; difference, 2.4 kg [95% CI, 1.0-3.7]; P = .002). Both groups had significant improvements in body composition, fitness, physical activity, and diet, with no significant difference between groups.

CONCLUSIONS AND RELEVANCE

Among young adults with a BMI between 25 and less than 40, the addition of a wearable technology device to a standard behavioral intervention resulted in less weight loss over 24 months. Devices that monitor and provide feedback on physical activity may not offer an advantage over standard behavioral weight loss approaches.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01131871.

Seasonal changes in objectively measured sedentary behavior and physical activity in Japanese primary school children

BACKGROUND

The recent prevalence of obesity in Japanese children is much higher compared to 1980. The present study compared daily sedentary behavior (SB) and physical activity (PA) between the school year and summer vacation in Japanese primary school children.

METHODS

Participants were 98 Japanese boys (8.9 ± 1.8 years at baseline) and 111 girls (9.1 ± 1.8 years). SB and PA were measured in May (school term) and July/August (summer vacation), 2011. SB and PA were assessed using a triaxial accelerometer (Active style Pro HJA-350IT, Omron Healthcare) for 7 consecutive days. The average number of minutes spent in SB (no more than 1.5 metabolic equivalents (METs)), light intensity activity (LPA; more than 1.5 to less than 3.0 METs) and moderate-to-vigorous physical activity (MVPA; 3.0 METs or more), and step counts were calculated for each individual. Moreover, the determinants/moderators of changes in SB and PA were examined.

RESULTS

Daily SB was significantly higher in the summer vacation than in the school year for both boys and girls (p < 0.05). Ambulatory and total LPA and MVPA, non-ambulatory LPA and step counts were lower in summer vacation in both genders (p < 0.001). Moreover, non-ambulatory MVPA was significantly lower in the summer vacation than in the school year for girls (p < 0.001). The decrease in non-ambulatory MVPA in boys and increase in SB in girls were significantly lower in those who participated in sports compared to those who did not (p < 0.040 or p < 0.033). The change in SB for boys was significantly associated with having a TV in the bedroom (p < 0.022).

CONCLUSIONS

These findings show that primary school children in Japan are less active in the summer vacation, as indicated by both higher SB and lower LPA and ambulatory MVPA in both genders. Moreover, the seasonal change in non-ambulatory MVPA for Japanese children was affected by gender. This study also suggests that sports participation and bedroom TV ownership may moderate seasonal changes in PA and SB. The results emphasize the need to take summer vacation into account when planning interventions aimed at decreasing SB or increasing PA in Japanese children.

Composition of objectively measured physical activity and sedentary behaviour participation across the school-day, influence of gender and weight status: cross-sectional analyses among disadvantaged Victorian school children

BACKGROUND

The after-school period has been described as the 'critical window' for physical activity (PA) participation. However, little is known about the importance of this window compared with the before and during-school period among socioeconomically disadvantaged children, and influence of gender and weight status.

METHODS

39 out of 156 (RR=25%) invited primary schools across 26 local government areas in Victoria, Australia, consented to participate with 856 children (RR=36%) participating in the wider study. The analysis sample included 298 Grade 4 and Grade 6 children (mean age: 11.2±1.1; 44% male) whom met minimum accelerometry wear-time criteria and had complete height, weight and health-behaviours questionnaire data. Accelerometry measured duration in daily light-intensity PA (LPA), moderate-to-vigorous PA (MVPA) and sedentary time (ST) was calculated for before-school=8-8:59, during-school=9:00-15:29 and after-school=15:30-18:00. Bivariate and multivariable linear regression analyses were conducted.

RESULTS

During-school represented the greatest accumulation of LPA and MVPA compared with the before and after-school periods. Boys engaged in 102 min/day of LPA (95% CI 98.5 to 104.9) and 62 min/day of MVPA (95% CI 58.9 to 64.7) during-school; girls engaged in 103 min/day of LPA (95% CI 99.7 to 106.5) and 45 min/day of MVPA (95% CI 42.9 to 47.4). Linear regression models indicated that girls with overweight or obesity engaged in significantly less LPA, MVPA and more time in ST during-school.

CONCLUSIONS

This study highlights the importance of in-school PA compared with after-school PA among socioeconomically disadvantage children whom may have fewer resources to participate in after-school PA.

Validation study of Polar V800 accelerometer

BACKGROUND

The correct quantification of physical activity (PA) and energy expenditure (EE) in daily life is an important target for researchers and professionals. The objective of this paper is to study the validity of the Polar V800 for the quantification of PA and the estimation of EE against the ActiGraph (ActiTrainer) in healthy young adults.

METHODS

Eighteen Caucasian active people (50% women) aged between 19-23 years wore an ActiTrainer on the right hip and a Polar V800 on the preferred wrist during 7 days. Paired samples t-tests were used to analyze differences in outcomes between devices, and Pearson's correlation coefficients to examine the correlation between outcomes. The agreement was studied using the Bland-Altman method. Also, the association between the difference and the magnitude of the measurement (heteroscedasticity) was examined. Sensitivity, specificity and area under the receiver operating characteristic curve (ROC-AUC value) were calculated to evaluate the ability of the devices to accurately define a person who fulfills the recommendation of 10,000 daily steps.

RESULTS

The devices significantly differed from each other on all outcomes (P<0.05), except for Polar V800's alerts vs. ActiTrainer's 1 hour sedentary bouts (P=0.595) and Polar V800's walking time vs. ActiTrainer's lifestyle time (P=0.484). Heteroscedasticity analyses were significant for all outcomes, except for Kcal and sitting time. The ROC-AUC value was fair (0.781±0.048) and the sensitivity and specificity was 98% and 58%, respectively.

CONCLUSIONS

The Polar V800 accelerometer has a comparable validity to the accelerometer in free-living conditions, regarding "1 hour sedentary bouts" and "V800's walking time vs. ActiTrainer's lifestyle time" in young adults.

The feasibility and acceptability of trial procedures for a pragmatic randomised controlled trial of a structured physical activity intervention for people diagnosed with colorectal cancer: findings from a pilot trial of cardiac rehabilitation versus usual care (no rehabilitation) with an embedded qualitative study

Background

Pilot and feasibility work is conducted to evaluate the operational feasibility and acceptability of the intervention itself and the feasibility and acceptability of a trials’ protocol design. The Cardiac Rehabilitation In Bowel cancer (CRIB) study was a pilot randomised controlled trial (RCT) of cardiac rehabilitation versus usual care (no rehabilitation) for post-surgical colorectal cancer patients. A key aim of the pilot trial was to test the feasibility and acceptability of the protocol design.

Methods

A pilot RCT with embedded qualitative work was conducted in three sites. Participants were randomly allocated to cardiac rehabilitation or usual care groups. Outcomes used to assess the feasibility and acceptability of key trial parameters were screening, eligibility, consent, randomisation, adverse events, retention, completion, missing data, and intervention adherence rates. Colorectal patients’ and clinicians’ perceptions and experiences of the main trial procedures were explored by interview.

Results

Quantitative study. Three sites were involved. Screening, eligibility, consent, and retention rates were 79 % (156/198), 67 % (133/198), 31 % (41/133), and 93 % (38/41), respectively. Questionnaire completion rates were 97.5 % (40/41), 75 % (31/41), and 61 % (25/41) at baseline, follow-up 1, and follow-up 2, respectively. Sixty-nine percent (40) of accelerometer datasets were collected from participants; 31 % (20) were removed for not meeting wear-time validation.

Qualitative study: Thirty-eight patients and eight clinicians participated. Key themes were benefits for people with colorectal cancer attending cardiac rehabilitation, barriers for people with colorectal cancer attending cardiac rehabilitation, generic versus disease-specific rehabilitation, key concerns about including people with cancer in cardiac rehabilitation, and barriers to involvement in a study about cardiac rehabilitation.

Conclusions

The study highlights where threats to internal and external validity are likely to arise in any future studies of similar structured physical activity interventions for colorectal cancer patients using similar methods being conducted in similar contexts. This study shows that there is likely to be potential recruitment bias and potential imprecision due to sub-optimal completion of outcome measures, missing data, and sub-optimal intervention adherence. Hence, strategies to manage these risks should be developed to stack the odds in favour of conducting successful future trials.

Trial registration

ISRCTN63510637

New insights into discrepancies between self-reported and accelerometer-measured moderate to vigorous physical activity among women - the mPED trial

Background

The aims of this report were 1) to describe the duration of moderate to vigorous physical activity (MVPA) and the proportion of participants meeting the recommended criterion of at least 150 min of MVPA per week as measured by the 7 Day Physical Activity Recall Questionnaire (7D-PAR) and accelerometer among women who were enrolled in the mPED trial; 2) to assess the level of agreement of the two measures using a Bland-Altman plot; and 3) to describe the positive and negative predictive values (PPV and NPV, respectively) of meeting the guidelines by calculating the percentage of women meeting the physical activity recommendation by the 7D-PAR who also met this recommendation based on data from the accelerometer.

Methods

Baseline data on duration of MVPA from the mPED trial were analyzed for 215 women. Among the women who met the recommended criterion by the 7D-PAR (self-report), we calculated the proportion of individuals who also met it by the accelerometer (objective measure). A Bland Altman Plot was used to assess concordance between the two measures.

Results

The mean age was 52.4 (±11.2) years; 54.4 % were white; and 48.8 % were single or divorced. While median MVPA was 160 min/week by the 7D-PAR, it was only 24 min/week in the accelerometer. A total of 117 women met the 150-min criterion by the 7D-PAR. Of these, only 18 also met the criterion by the objective measure (PPV 15.4 %, 95 % CI 9.4–23.2 %). Among the 98 women who did not meet the criterion by the 7D-PAR, none met it by the accelerometer (NPV 100 %). A Bland Altman plot showed the mean difference of +145 min between the two measures with a 95 % limit of agreement at + 471 to −181 min.

Conclusions

The large discrepancy between the self-reported and objective measures of MVPA meeting the 150-min criterion suggests that self-reported physical activity measures should be used with caution in intervention studies. While our data suggest that self-report could be used to identify a physically inactive sample, it would be likely to over-estimate the proportions of women who become active in one or both arms of trials of interventions promoting MVPA.

Trial registration

ClinicalTrials.gov NCT01280812

Modulation of Irisin and Physical Activity on Executive Functions in Obesity and Morbid obesity

Whether the executive profile is different between obesity (OB) and morbid obesity (MO) remains unclear. Recent evidence suggests that physical activity (PA) can act as a cognitive enhancer. Irisin is a recently discovered hormone associated with some of the positive effects of PA. The objective of the study was to investigate the executive profile in OB and MO, and to explore the role of PA and irisin. 114 participants were included (21 OB, 44 MO and 49 healthy controls-HC) in the study and assessed with the Wisconsin Card Sorting Test, Stroop Color and Word Test, and Iowa Gambling Task. All participants were female, aged between 18 and 60 years. Results showed a similar dysfunctional profile on decision making in OB and MO compared with HC. Thus, no specific neuropsychological profiles between OB and MO can be clearly observed in our sample. However, a negative correlation was found between irisin and executive functioning. These results demonstrate a specific executive profile in OB and a relevant and negative modulation of irisin on executive functioning. Although irisin might be a promising target for the treatment of obesity, its effects on cognition might be considered when thinking about its therapeutic use.

A randomized trial comparing two interventions to increase physical activity among patients undergoing bariatric surgery

OBJECTIVE

To test the effectiveness of two levels of physical activity interventions before and up to 6½ months after bariatric surgery.

METHODS

Before surgery, individuals completed submaximal exercise testing on a treadmill. After random assignment to standard care, pedometer use, or exercise counseling plus pedometer, participants wore an accelerometer for approximately 2 weeks and returned it to the bariatric center before surgery and 2, 4, and 6 months postoperatively.

RESULTS

Individuals in exercise counseling plus pedometer had higher steps per day and bout minutes of exercise per week than standard care and pedometer use over the course of the study. There were no group differences related to exercise tolerance; however, all groups made significant improvement. There was no statistically significant change in sedentary or light activity nor was there a difference between groups.

CONCLUSIONS

Exercise counseling using pedometers increases physical activity from the perioperative period to 6½ months after surgery, but providing pedometers without professional feedback may not be more effective than standard bariatric surgery treatments. Rapid weight loss increases exercise tolerance and may mask the fitness improvements achieved through a modest physical activity intervention during the first 6 months after bariatric surgery.

The use of cardiac rehabilitation services to aid the recovery of patients with bowel cancer: a pilot randomised controlled trial with embedded feasibility study

Background

Colorectal cancer (CRC) survivors are not meeting the recommended physical activity levels associated with improving their chances of survival and quality of life. Rehabilitation could address this problem.

Objectives

The aims of the Cardiac Rehabilitation In Bowel cancer study were to assess whether or not cardiac rehabilitation is a feasible and acceptable model to aid the recovery of people with CRC and to test the feasibility and acceptability of the protocol design.

Design

Intervention testing and feasibility work (phase 1) and a pilot randomised controlled trial with embedded qualitative study (phase 2), supplemented with an economic evaluation. Randomisation was to cardiac rehabilitation or usual care. Outcomes were differences in objective measures of physical activity and sedentary behaviour, self-reported measures of quality of life, anxiety, depression and fatigue. Qualitative work involved patients and clinicians from both cancer and cardiac specialties.

Setting

Three colorectal cancer wards and three cardiac rehabilitation facilities.

Participants

Inclusion criteria were those who were aged > 18 years, had primary CRC and were post surgery.

Results

Phase 1 (single site) – of 34 patient admissions, 24 (70%) were eligible and 4 (17%) participated in cardiac rehabilitation. Sixteen clinicians participated in an interview/focus group. Modifications to trial procedures were made for further testing in phase 2. Additionally, 20 clinicians in all three sites were trained in cancer and exercise, rating it as excellent. Phase 2 (three sites) – screening, eligibility, consent and retention rates were 156 (79%), 133 (67%), 41 (31%) and 38 (93%), respectively. Questionnaire completion rates were 40 (97.5%), 31 (75%) and 25 (61%) at baseline, follow-up 1 and follow-up 2, respectively. Forty (69%) accelerometer data sets were analysed; 20 (31%) were removed owing to invalid data.

Qualitative study

CRC and cardiac patients and clinicians were interviewed. Key themes were benefits and barriers for people with CRC attending cardiac rehabilitation; generic versus disease-specific rehabilitation; key concerns of the intervention; and barriers to participation (CRC participants only).

Economic evaluation

The average out-of-pocket expenses of attending cardiac rehabilitation were £50. The costs of cardiac rehabilitation for people with cancer are highly dependent on whether it involves accommodating additional patients in an already existing service or setting up a completely new service.

Limitations and conclusions

The main limitation is that this is a small feasibility and pilot study. The main novel finding is that cardiac rehabilitation for cancer and cardiac patients together is feasible and acceptable, thereby challenging disease-specific rehabilitation models.

Future work

This study highlighted important challenges to doing a full-scale trial of cardiac rehabilitation but does not, we believe, provide sufficient evidence to reject the possibility of such a future trial. We recommend that any future trial must specifically address the challenges identified in this study, such as suboptimal consent, completion, missing data and intervention adherence rates and recruitment bias, and that an internal pilot trial be conducted. This should have clear ‘stop–proceed’ rules that are formally reviewed before proceeding to the full-scale trial.

Trial registration

Current Controlled Trials ISRCTN63510637.

Funding

This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full inHealth Services and Delivery Research; Vol. 4, No. 24. See the NIHR Journals Library website for further project information.

Calibration of context-specific survey items to assess youth physical activity behaviour

This study tests calibration models to re-scale context-specific physical activity (PA) items to accelerometer-derived PA. A total of 195 4th-12th grades children wore an Actigraph monitor and completed the Physical Activity Questionnaire (PAQ) one week later. The relative time spent in moderate-to-vigorous PA (MVPA_%) obtained from the Actigraph at recess, PE, lunch, after-school, evening and weekend was matched with a respective item score obtained from the PAQ's. Item scores from 145 participants were calibrated against objective MVPA_% using multiple linear regression with age, and sex as additional predictors. Predicted minutes of MVPA for school, out-of-school and total week were tested in the remaining sample (n = 50) using equivalence testing. The results showed that PAQ β-weights ranged from 0.06 (lunch) to 4.94 (PE) MVPA_% (P < 0.05) and models root mean square error ranged from 4.2% (evening) to 20.2% (recess). When applied to an independent sample, differences between PAQ and accelerometer MVPA at school and out-of-school ranged from -15.6 to +3.8 min and the PAQ was within 10-15% of accelerometer measured activity. This study demonstrated that context-specific items can be calibrated to predict minutes of MVPA in groups of youth during in- and out-of-school periods.

CANPLAY study: Secular trends in steps/day amongst 5-19year-old Canadians between 2005 and 2014

INTRODUCTION

The Canadian Physical Activity Levels Among Youth (CANPLAY) study collected pedometer data from eight surveys between 2005 and 2014, making it a unique database of objective population physical activity surveillance. The purpose of this study was to describe secular physical activity trends for 5-19year olds.

METHODS

Canadian children from nationally representative samples (10,000 recruited, n≅5500 per survey) were mailed a pedometer kit, asked to wear the pedometer for 7 consecutive days, log steps daily, then return the log by mail. Weighted medians and prevalence estimates were calculated. Trends were tested by χ(2) test of independence.

RESULTS

An overall median of 10,935 steps/day was taken by Canadian children 5-19years of age (n=43,806) across the eight surveys. Steps/day increased between 2005-06 and 2007-08, then decreased in 2012-14. The prevalence of taking sufficient steps/day (defined as ≥10,000 steps/day for 5year olds, ≥13,000 steps/day for 6-11year-old boys; ≥11,000 steps/day for 6-11year-old girls; and ≥10,000 steps/day for 12-19year olds;) also increased then decreased over time, whereas the prevalence of accumulating <7000 steps/day generally increased over time. Trends were significant for boys, girls and each age group.

DISCUSSION

The CANPLAY surveillance system provided comparable data at multiple time points over 9years. An overall shift in the distribution of steps/day towards a less active lifestyle occurred between 2005-06 and 2012-14 for boys, girls and each age group. This provides evidence that the national policy goal to increase children's steps/day by 2015 has not been met.

An Internet-Based Physical Activity Intervention to Improve Quality of Life of Inactive Older Adults: A Randomized Controlled Trial

Background

Increasing physical activity is a viable strategy for improving both the health and quality of life of older adults.

Objective

The aim of this study was to assess if an Internet-based intervention aimed to increase physical activity was effective in improving quality of life of inactive older adults. In addition, we analyzed the effect of the intervention on quality of life among those participants who successfully reached their individually targeted increase in daily physical activity as indicated by the intervention program, as well as the dose-response effect of increasing physical activity on quality of life.

Methods

The intervention was tested in a randomized controlled trial and was comprised of an Internet program—DirectLife (Philips)—aimed at increasing physical activity using monitoring and feedback by accelerometry and feedback by digital coaching (n=119). The control group received no intervention (n=116). Participants were inactive 60-70-year-olds and were recruited from the general population. Quality of life and physical activity were measured at baseline and after 3 months using the Research ANd Development 36-item health survey (RAND-36) and wrist-worn triaxial accelerometer, respectively.

Results

After 3 months, a significant improvement in quality of life was seen in the intervention group compared to the control group for RAND-36 subscales on emotional and mental health (2.52 vs -0.72, respectively; P=.03) and health change (8.99 vs 2.03, respectively; P=.01). A total of 50 of the 119 participants (42.0%) in the intervention group successfully reached their physical activity target and showed a significant improvement in quality of life compared to the control group for subscales on emotional and mental health (4.31 vs -0.72, respectively; P=.009) and health change (11.06 vs 2.03, respectively; P=.004). The dose-response analysis showed that there was a significant association between increase in minutes spent in moderate-to-vigorous physical activity (MVPA) and increase in quality of life.

Conclusions

Our study shows that an Internet-based physical activity program was effective in improving quality of life in 60-70-year-olds after 3 months, particularly in participants that reached their individually targeted increase in daily physical activity.

Trial Registration

Nederlands Trial Register: NTR 3045; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=3045 (Archived by WebCite at http://www.webcitation.org/6fobg2sjJ)

Is it on? An algorithm for discerning wrist-accelerometer non-wear times from sleep/wake activity

The accuracy of sleep/wake estimates derived with actigraphy is often dependent on researchers being able to discern non-wear times from sleep or quiescent wakefulness when confronted by discrepancies in a sleep log. Without knowing when an accelerometer is being worn, non-wear could be inferred from periods of inactivity unlikely to occur while in bed. Data collected in our laboratory suggest that more than 50% of inactive periods during time in bed are <8 min in duration. This duration may be an appropriate minimum threshold for routine non-wear classification during self-reported wake. Higher thresholds could be chosen to derive non-wear definitions for self-reported bedtimes depending on the desired level of certainty. To determine non-wear at thresholds of 75%, 95% and 99%, for example, would require periods of inactivity lasting ≥18 min, ≥53 min and ≥85 min, respectively.

Daily Life Physical Activity Modulates the Effects of an Exercise Program on Lower-Extremity Physical Function in Japanese Older Adults

BACKGROUND AND PURPOSE

Decreasing daily life physical activity (PA) outside an exercise program might hinder the benefit of that program on lower-extremity physical function (LEPF) in older adults. The purpose of this study was to investigate how daily life PA modulates the effects of an exercise program on LEPF.

METHODS

The participants were 46 community-dwelling older adults (mean age, 70.1 ± 3.5 years) in Kasama City, a rural area in Japan. All participated in a fall-prevention program called square-stepping exercise once a week for 11 weeks. We evaluated their daily life PA outside the exercise program with pedometers and calculated the average daily step counts during the early and late periods of the program. We divided participants into 2 groups on the basis of whether or not they decreased PA by more than 1000 steps per day between the early and late periods. To ascertain the LEPF benefits induced by participating in the exercise program, we measured 5 physical performance tests before and after the intervention: 1-leg stand, 5-time sit-to-stand, Timed Up and Go (TUG), habitual walking speed, and choice-stepping reaction time (CSRT). We used a 2-way analysis of variance to confirm the interaction between the 2 groups and the time effect before and after the intervention.

RESULTS

During the exercise program, 8 participants decreased their daily life PA (early period, 6971 ± 2771; late period, 5175 ± 2132) and 38 participants maintained PA (early period, 6326 ± 2477; late period, 6628 ± 2636). Both groups significantly improved their performance in TUG and CSRT at the posttest compared with the baseline. A significant group-by-time interaction on the walking speed (P = .038) was observed: participants who maintained PA improved their performance more than those who decreased their PA.

DISCUSSION

Square-stepping exercise requires and strengthens dynamic balance and agility, which contributed to the improved time effects that occurred in TUG and CSRT. On the contrary, because PA is positively associated with walking speed, maintaining daily life PA outside an exercise program may have a stronger influence on walking speed. To enhance the effectiveness of an exercise program for young-old adults, researchers and instructors should try to maintain the participant's daily life PA outside the program.

CONCLUSION

Regardless of decreasing or maintaining daily life PA, the square-stepping exercise program could improve aspects of LEPF that require complex physical performance. However, a greater effect can be expected when participants maintain their daily life PA outside the exercise program.

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.

Missing value imputation for physical activity data measured by accelerometer

An accelerometer, a wearable motion sensor on the hip or wrist, is becoming a popular tool in clinical and epidemiological studies for measuring the physical activity. Such data provide a series of activity counts at every minute or even more often and displays a person's activity pattern throughout a day. Unfortunately, the collected data can include irregular missing intervals because of noncompliance of participants and therefore make the statistical analysis more challenging. The purpose of this study is to develop a novel imputation method to handle the multivariate count data, motivated by the accelerometer data structure. We specify the predictive distribution of the missing data with a mixture of zero-inflated Poisson and Log-normal distribution, which is shown to be effective to deal with the minute-by-minute autocorrelation as well as under- and over-dispersion of count data. The imputation is performed at the minute level and follows the principles of multiple imputation using a fully conditional specification with the chained algorithm. To facilitate the practical use of this method, we provide an R package accelmissing. Our method is demonstrated using 2003-2004 National Health and Nutrition Examination Survey data.

Demographic, clinical, psychosocial, and environmental correlates of objectively assessed physical activity among breast cancer survivors

Purpose

The aim of this study was to identify demographic, clinical, psychosocial, and environmental correlates of objectively assessed physical activity among breast cancer survivors.

Methods

Baseline data were utilized from 574 female breast cancer survivors who participated in three different intervention studies: Resistance and Endurance exercise After ChemoTherapy (REACT), Exercise and Nutrition Routine Improving Cancer Health (ENRICH), and Move More for Life (MM4L). Participants were eligible if they were aged ≥18 years and had completed primary cancer treatment. Physical activity was objectively assessed by accelerometers or pedometers. Participants completed self-reported questionnaires on demographic, psychosocial, and environmental factors. Information regarding clinical factors was obtained from medical records or patient self-report. Multivariable linear regression analyses were applied on the pooled dataset to identify factors that were significantly correlated with physical activity. In addition, the explained variance of the model was calculated.

Results

The multivariable regression model revealed that older age, (β = −0.01, 95 %CI = −0.02; −0.003), higher body mass index (β = −0.05, 95 %CI = −0.06; −0.03), lower self-efficacy (β = 0.2, 95 %CI = 0.08; 0.2), and less social support (β = 0.1, 95 %CI = 0.05; 0.2) were significantly correlated with lower physical activity. This model explained 15 % of the variance in physical activity.

Conclusion

Age, body mass index, self-efficacy, and social support were significantly correlated with objectively assessed physical activity in breast cancer survivors. It may therefore be recommended that physical activity intervention studies in these women target those who are older, and have a higher body mass index, and should operationalize behavior change strategies designed to enhance self-efficacy and social support.

Trial registration

The REACT study is registered at the Netherlands Trial Register [NTR2153]. The ENRICH study is registered at Australian New Zealand Clinical Trials Register [ANZCTRN12609001086257]. And the MM4L study is registered at Australian New Zealand Clinical Trials Register [ACTRN12611001061921]

Identifying children's nocturnal sleep using 24-h waist accelerometry

PURPOSE

The purposes of this study were 1) to add layers and features to a previously published fully automated algorithm designed to identify children's nocturnal sleep and to exclude episodes of nighttime nonwear/wakefulness and potentially misclassified daytime sleep episodes and 2) to validate this refined sleep algorithm (RSA) against sleep logs.

METHODS

Forty-five fourth-grade school children (51% female) participants were asked to log evening bedtime and morning wake time and wear an ActiGraph GT3X+ (ActiGraph LLC, Pensacola, FL) accelerometer at their waist for seven consecutive days. Accelerometers were distributed through a single school participating in the Baton Rouge, USA, site of the International Study of Childhood Obesity, Lifestyle, and the Environment. We compared log-based variables of sleep period time (SPT), bedtime, and wake time to corresponding accelerometer-determined variables of total sleep episode time, sleep onset, and sleep offset estimated with the RSA. In addition, SPT and sleep onset estimated using standard procedures combining sleep logs and accelerometry (Log + Accel) were compared to the RSA-derived values.

RESULTS

RSA total sleep episode time (540 ± 36 min) was significantly different from Log SPT (560 ± 24 min), P = 0.003, but not different from Log + Accel SPT (549 ± 24 min), P = 0.15. Significant and moderately high correlations were apparent between RSA-determined variables and those using the other methods (r = 0.61 to 0.74). There were no differences between RSA and Log + Accel estimates of sleep onset (P = 0.15) or RSA sleep offset and log wake time (P = 0.16).

CONCLUSIONS

The RSA is a refinement of our previous algorithm, allowing researchers who use a 24-h waist-worn accelerometry protocol to distinguish children's nocturnal sleep (including night time wake episodes) from daytime activities.

Long-term Surveillance of Physical Activity Habits of Latinas Enrolled in a 12-Month Physical Activity Intervention

BACKGROUND

Long-term physical activity surveillance has not been conducted among Latinas. This study explored the variability of daily physical activity habits of inactive adult Latinas participating in a 12-month physical activity intervention.

METHODS

We collected objective physical activity data (pedometer) from 139 Spanish speaking Latinas (age = 41.6 ± 10.1 years; BMI = 29.6 ± 4.3 kg/m2) enrolled in a 12-month physical activity intervention. Total and aerobic steps (>100 steps/minute) were computed by year, season, month, day of week, time of day, and hour.

RESULTS

Participants walked an average of 6509 steps/day of which 1303 (20%) were aerobic steps. Significant physical activity differences were observed for subgroups including generational status, education, employment, income, marital status and health literacy. Significant and similar differences were observed for both total steps and aerobic steps for day of the week (weekdays > weekends) and season (summer > spring > fall > winter). Opposing trends were observed over the course of the day for total steps (early afternoon > late morning > late afternoon > early morning > evening) and aerobic steps (early morning > evening > late morning > late afternoon > early afternoon).

CONCLUSIONS

Both seasonality and week day predicted physical activity habits of Latinas. This is the first long-term study to track daily physical activity habits of Latinas. These data have potential to inform the design of future physical activity interventions targeting Latinas.

Physical activity and sedentary behaviour among Asian and Anglo-Australian adolescents

ISSUE ADDRESSED

Evidence suggests that physical activity (PA) and sedentary behaviour (SB) participation varies among culturally and linguistically diverse (CALD) adolescents. The present study examined differences in PA and SB among a CALD sample of Chinese Australian, South-east Asian and Anglo-Australian adolescents.

METHODS

Data from 286 adolescents aged 12-16 years involved in the Chinese and Australian Adolescent Health Survey in metropolitan Melbourne, Australia, were analysed. Accelerometry outcomes included median activity counts per minute (counts x min(-1)) and minutes per day (min x day(-1)) spent in light-intensity PA (LPA), moderate-to-vigorous-intensity PA (MVPA) and sedentary time (ST). Kruskal-Wallis one-way analysis of variance and sequential multiple hierarchical linear regressions were used to examine CALD differences in PA and ST.

RESULTS

Multivariate analyses of accelerometry data found Chinese Australian and South-east Asian adolescents engaged in significantly less daily MVPA (5-8 min x day(-1)) and LPA (50-58 min x day(-1); P < 0.05), but greater daily ST (40-41 min x day(-1)), than Anglo-Australian adolescents, after adjusting for age, gender and socioeconomic category.

CONCLUSION

The results demonstrate lower engagement in daily MVPA and LPA and greater engagement in ST using accelerometry among Chinese Australian and South-east Asian adolescents compared with Anglo-Australian adolescents. These findings have important public health implications in furthering our understanding of CALD differences in PA and SB. SO WHAT? An understanding of the CALD differences in physical activity and sedentary behaviour among Australian adolescents has important implications for intervention planning and delivery as well as the wider health implications of these behaviours. This article furthers the current understanding of CALD adolescents' participation in physical activity and sedentary behaviour, of which limited information is available.

The association between park visitation and physical activity measured with accelerometer, GPS, and travel diary

Public parks are promoted as places that support physical activity (PA), but evidence of how park visitation contributes to overall PA is limited. This study observed adults living in the Seattle metropolitan area (n=671) for one week using accelerometer, GPS, and travel diary. Park visits, measured both objectively (GPS) and subjectively (travel diary), were temporally linked to accelerometer-measured PA. Park visits occurred at 1.4 per person-week. Participants who visited parks at least once (n=308) had an adjusted average of 14.3 (95% CI: 8.9, 19.6)min more daily PA than participants who did not visit a park. Even when park-related activity was excluded, park visitors still obtained more minutes of daily PA than non-visitors. Park visitation contributes to a more active lifestyle, but is not solely responsible for it. Parks may best serve to complement broader public health efforts to encourage PA.

Validity and reliability of a modified english version of the physical activity questionnaire for adolescents

Background

Adaptation of physical activity self-report questionnaires is sometimes required to reflect the activity behaviours of diverse populations. The processes used to modify self-report questionnaires though are typically underreported. This two-phased study used a formative approach to investigate the validity and reliability of the Physical Activity Questionnaire for Adolescents (PAQ-A) in English youth. Phase one examined test content and response process validity and subsequently informed a modified version of the PAQ-A. Phase two assessed the validity and reliability of the modified PAQ-A.

Methods

In phase one, focus groups (n = 5) were conducted with adolescents (n = 20) to investigate test content and response processes of the original PAQ-A. Based on evidence gathered in phase one, a modified version of the questionnaire was administered to participants (n = 169, 14.5 ± 1.7 years) in phase two. Internal consistency and test-retest reliability were assessed using Cronbach’s alpha and intra-class correlations, respectively. Spearman correlations were used to assess associations between modified PAQ-A scores and accelerometer-derived physical activity, self-reported fitness and physical activity self-efficacy.

Results

Phase one revealed that the original PAQ-A was unrepresentative for English youth and that item comprehension varied. Contextual and population/cultural-specific modifications were made to the PAQ-A for use in the subsequent phase. In phase two, modified PAQ-A scores had acceptable internal consistency (α = 0.72) and test-retest reliability (ICC = 0.78). Modified PAQ-A scores were significantly associated with objectively assessed moderate-to-vigorous physical activity (r = 0.39), total physical activity (r = 0.42), self-reported fitness (r = 0.35), and physical activity self-efficacy (r = 0.32) (p ≤ 0.01).

Conclusions

The modified PAQ-A had acceptable internal consistency and test-retest reliability. Modified PAQ-A scores displayed weak-to-moderate correlations with objectively measured physical activity, self-reported fitness, and self-efficacy providing evidence of satisfactory criterion and construct validity, respectively. Further testing with more diverse English samples is recommended to provide a more complete assessment of the tool.

Electronic supplementary material

The online version of this article (doi:10.1186/s13690-016-0115-2) contains supplementary material, which is available to authorized users.

Friendship Network Characteristics Are Associated with Physical Activity and Sedentary Behavior in Early Adolescence

INTRODUCTION

There is limited understanding of the association between peer social networks and physical activity (PA), sedentary and screen-related behaviors. This study reports on associations between personal network characteristics and these important health behaviors for early adolescents.

METHODS

Participants were 310 students, aged 11-13 years, from fifteen randomly selected Victorian primary schools (43% response rate). PA and sedentary behaviors were collected via accelerometer and self-report questionnaire, and anthropometric measures via trained researchers. Participants nominated up to fifteen friends, and described the frequency of interaction and perceived activity intensity of these friends. Personal network predictors were examined using regression modelling for PA and sedentary/screen behavior.

RESULTS

Perceived activity levels of friends, and friendships with very frequent interaction were associated with outside-of-school PA and/or sedentary/screen time. Differences according to sex were also observed in the association between network characteristics and PA and sedentary time. A higher number of friends and greater proportion of same sex friends were associated with boys engaging in more moderate-to-vigorous PA outside of school hours. PA intensity during school-day breaks was positively associated with having a greater proportion of friends who played sports for girls, and a greater proportion of male friends for boys.

CONCLUSION

Friendship network characteristics are associated with PA and sedentary/screen time in late childhood/early adolescence, and these associations differ by sex. The positive influence of very active peers may be a promising avenue to strengthen traditional interventions for the promotion of PA and reduction in screen time.

Unique contributions of ISCOLE to the advancement of accelerometry in large studies

Accelerometry has become a mainstay approach for objectively monitoring children's physical activity and sedentary time in epidemiological studies. The magnitude of effort underlying successful data collection, management and treatment is prodigious and its complexity has been associated with increasingly diverse methodological choices that, while defensible relative to specific research questions, conspire to undermine the ability to compare results between studies. Although respecting widespread calls for best practices, it is also important to openly share tools and resources supporting potential improvements to research practice and study design, thus allowing others to replicate, further improve, and/or otherwise build on this foundation. The International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE) is a large multinational study that included accelerometer-based measures of physical activity, sedentary time and sleep. This review summarizes the unique contributions of ISCOLE to the advancement of accelerometry in large studies of children's behavior, and in particular: (1) open-access publication of the ISCOLE accelerometry Manual of Operations; (2) 24-h waist-worn accelerometry protocol; (3) identification and extraction of nocturnal total sleep episode time (with open access to editable SAS syntax); (4) development of the first interpretive infrastructure for identifying and defining an evolved list of sleep-related variables from 24-h waist-worn accelerometry; (5) provision of a detailed model for reporting accelerometer paradata (administrative data related to accelerometry); and (6) cataloging the most detailed and defensible list of accelerometry-derived physical activity and sedentary time variables to date. The novel tools and resources associated with these innovations are shared openly in an effort to support methodological harmonization and overall advancement of accelerometry in large epidemiological studies.

Short-term weight loss with diet and physical activity in young adults: The IDEA study

OBJECTIVE

This study examined the effect of a behavioral weight loss intervention (BWLI) on young adults (age = 18-35 years).

METHODS

Participants (N = 470) enrolled in a 6-month BWLI that included weekly group sessions, a prescribed energy-restricted diet, and moderate to vigorous physical activity (MVPA). Assessments included weight, body composition, fitness, lipids, glucose, insulin, resting blood pressure and heart rate, physical activity, and dietary intake. Data are presented as median [25th, 75th percentiles].

RESULTS

Retention was 90% (N = 424; age: 30.9 [27.8, 33.7] years; BMI: 31.2 [28.4, 34.3] kg m(-2) ). Participants completed 87.5% [76.1%, 95.5%] of scheduled intervention contacts. Weight and body fat decreased while fitness increased (P < 0.0001). MVPA in bouts ≥10 min increased (P < 0.0001), though total MVPA did not change significantly. Sedentary time decreased (P = 0.03). Energy and percent fat intake decreased, while percent carbohydrate and protein intake increased (P < 0.0001). Systolic and diastolic blood pressure, total cholesterol, LDL cholesterol, triglycerides, glucose, and insulin decreased (P < 0.0001).

CONCLUSIONS

A 6-month BWLI produced favorable changes in dietary intake and physical activity and elicited favorable changes in weight and other health outcomes in young adults. MVPA performed in bouts of ≥10 min was associated with greater weight loss, but sedentary behavior was not.

Intensity of bouted and sporadic physical activity and the metabolic syndrome in adults

Background. Physical activity guidelines for adults only recognize the health benefits of accumulating bouted moderate-to-vigorous physical activity (MVPA), or MVPA occurring over at least 10 consecutive minutes. There is a lack of evidence supporting the health benefits of other patterns and intensities of activity including sporadic MVPA (i.e., MVPA occurring in periods of fewer than 10 consecutive minutes) and light intensity physical activity (LIPA). The objective of this study was to examine the health benefits associated with physical activity that does not meet the physical activity guidelines criteria for bouted MVPA. Specifically, we examined the association between sporadic MVPA and bouted and sporadic LIPA with the metabolic syndrome. Methods. We studied a representative cross-sectional sample of 1,974 adults aged 20 years and older from the 2003-2006 US National Health and Nutrition Examination Survey. Physical activity was measured over 7 days using Actigraph AM-7164 accelerometers. Each minute over the 7-day measurement period was classified as being of a sedentary, light, or moderate-to-vigorous intensity. A 10 min threshold differentiated bouted activity from sporadic activity. Average minutes/day of sporadic LIPA, sporadic MVPA, bouted LIPA, bouted MVPA, and embedded MVPA (MVPA occurring within bouts of primarily LIPA) were calculated. Metabolic syndrome status was determined using established criteria. Associations were examined using logistic regression and controlled for relevant covariates. Results. For every 30 min/day of physical activity, the odds ratio (95% confidence interval) of the metabolic syndrome was reduced by 4% (1-7%) for bouted LIPA, 64% (51-71%) for bouted MVPA, and 57% (45-67%) for embedded MVPA. Sporadic LIPA was not independently associated with the metabolic syndrome. We could not examine the association between sporadic MVPA and the metabolic syndrome because participants accumulated such a marginal amount of this type of activity (i.e., median = 2 min/day, only 11% of participants accumulated ≥5 min/day). Conclusion. The intensity of non-bouted activity is important, as embedded MVPA had a stronger association with the metabolic syndrome than sporadic LIPA and a comparable association to bouted MVPA.

Volume and correlates of objectively measured physical activity and sedentary time in non-Hodgkin lymphoma survivors

OBJECTIVES

Few studies have measured the physical activity levels of non-Hodgkin lymphoma (NHL) survivors, and no previous studies have measured sedentary behavior levels in this population. This study used accelerometers to measure the physical activity and sedentary time levels of NHL survivors and examined the demographic, behavioral, and medical correlates of these behaviors.

METHODS

A total of 156 NHL survivors (mean age = 64 years) completed a questionnaire and wore an accelerometer for seven consecutive days during waking hours. Descriptive statistics were used to describe physical activity and sedentary time levels, and linear regression was used to investigate correlates of these behaviors.

RESULTS

Participants averaged 8.6 h of sedentary time per day (60% of their accelerometer wear time), 5.3 h of light-intensity physical activity (37%), and 30 min of moderate-intensity physical activity (3%). Only 12% of the participants accrued the duration of moderate-vigorous physical activity recommended by physical activity guidelines (30 min accrued in bouts of at least 10 min). Female participants, older participants, smokers, and participants with larger waist circumference had lower levels of moderate-to-vigorous intensity physical activity. Smokers and participants with larger waist circumference also had higher sedentary time levels.

CONCLUSION

The NHL survivors in this study spent the majority of their waking hours sedentary, and few met physical activity guidelines. The results of this study emphasize the need for more research exploring the health consequences of sedentary behavior and physical inactivity in NHL survivors. Copyright © 2015 John Wiley & Sons, Ltd.

Decline in objective physical activity over a 10-year period in a Japanese elementary school

Background

The purpose of this study was to examine the change in accelerometer-derived daily physical activity (PA) and activity record-derived daily activities over a 10-year period in urban elementary schoolchildren in Japan.

Methods

A total of 233 sixth-grade children (11–12 years old) in a same elementary school in Kyoto participated in the study (n = 125 and 108 in 1999 and 2009, respectively). The participant rate is 91.9 and 98.2 % in 1999 and 2009, respectively. The size and shape of the school district was not changed. The children were instructed to wear an accelerometer for 5 consecutive days of weekday and to keep minute-by-minute 24-h activity records with the assistance of their parents. The school-day scheduling was similar between 1999 and 2009 (29 and 27 sessions of 45-min class per week, respectively).

Results

From 1999 to 2009, step counts considerably decreased (20,832 vs. 12,237 steps per day in boys and 16,087 vs. 10,748 steps per day in girls; P < 0.001) with concomitant significant decreases in total energy expenditure (P = 0.011), activity energy expenditure (P < 0.001), and physical activity level (P < 0.001). Time spent playing outdoors and walking to school were also significantly less in 2009 than 1999 (P < 0.001). Accelerometer-measured PA was significantly associated with the amount of time spent playing outdoors and walking to school.

Conclusions

These results indicate that elementary schoolchildren in 2009 spend less time playing outdoors and walking to school, perform less PA, and take fewer steps than children of a decade ago.

Relationship between Objectively Measured Transportation Behaviors and Health Characteristics in Older Adults

This study used objective Global Positioning Systems (GPS) to investigate the relationship between pedestrian and vehicle trips to physical, cognitive, and psychological functioning in older adults living in retirement communities. Older adults (N = 279; mean age = 83 ± 6 years) wore a GPS and accelerometer for 6 days. Participants completed standard health measures. The Personal Activity and Location Measurement System (PALMS) was used to calculate the average daily number of trips, distance, and minutes traveled for pedestrian and vehicle trips from the combined GPS and accelerometer data. Linear mixed effects regression models explored relationships between these transportation variables and physical, psychological and cognitive functioning. Number, distance, and minutes of pedestrian trips were positively associated with physical and psychological functioning but not cognitive functioning. Number of vehicle trips was negatively associated with fear of falls; there were no other associations between the vehicle trip variables and functioning. Vehicle travel did not appear to be related to functioning in older adults in retirement communities except that fear of falling was related to number of vehicle trips. Pedestrian trips had moderate associations with multiple physical and psychological functioning measures, supporting a link between walking and many aspects of health in older adults.

GT3X+ accelerometer placement affects the reliability of step-counts measured during running and pedal-revolution counts measured during bicycling

Accelerometers provide a measure of step-count. Reliability and validity of step-count and pedal-revolution count measurements by the GT3X+ accelerometer, placed at different anatomical locations, is absent in the literature. The purpose of this study was to investigate the reliability and validity of step and pedal-revolution counts produced by the GT3X+ placed at different anatomical locations during running and bicycling. Twenty-two healthy adults (14 men and 8 women) completed running and bicycling activity bouts (5 minutes each) while wearing 6 accelerometers: 2 each at the waist, thigh and shank. Accelerometer and video data were collected during activity. Excellent reliability and validity were found for measurements taken from accelerometers mounted at the waist and shank during running (Reliability: intraclass correlation (ICC) ≥ 0.99; standard error of measurement (SEM) ≤1.0 steps;

VALIDITY

Pearson ≥ 0.99) and at the thigh and shank during bicycling (Reliability: ICC ≥ 0.99; SEM ≤1.0 revolutions;

VALIDITY

Pearson ≥ 0.99). Excellent reliability was found between measurements taken at the waist and shank during running (ICC ≥ 0.98; SEM ≤1.6 steps) and between measurements taken at the thigh and shank during bicycling (ICC ≥ 0.99; SEM ≤1.0 revolutions). These data suggest that the GT3X+ can be used for measuring step-count during running and pedal-revolution count during bicycling. Only shank placement is recommended for both activities.

Physical activity in anorexia nervosa: How relevant is it to therapy response?

OBJECTIVE

Elevated physical activity has been observed in some patients with anorexia nervosa (AN) despite their emaciated condition. However, its effects on treatment outcome remain unclear. This study aimed to examine objectively measured physical activity in this clinical population and how it might be related to a partial hospitalization therapy response, after considering potential confounders.

METHOD

The sample comprised 88 AN patients consecutively enrolled in a day hospital treatment program, and 116 healthy-weight controls. All participants were female and a baseline assessment took place using an accelerometer (Actiwatch AW7) to measure physical activity, the Eating Disorders Inventory-2 and the Depression subscale of the Symptom Checklist-Revised. Outcome was evaluated upon the termination of the treatment program by expert clinicians.

RESULTS

Although AN patients and controls did not differ in the average time spent in moderate-to-vigorous physical activity (MVPA) (P=.21), nor daytime physical activity (P=.34), fewer AN patients presented a high physical activity profile compared to the controls (37% vs. 61%, respectively; P=.014). Both lower levels of MVPA and greater eating disorder severity had a direct effect on a poor treatment outcome. Depression symptoms in the patients were associated with lower MVPA, as well as with an older age, a shorter duration of the disorder and greater eating disorder psychopathology.

CONCLUSIONS

There is a notable variation in the physical activity profile of AN patients, characterized by either low or very high patterns. Physical activity is a highly relevant issue in AN that must be taken into account during the treatment process.

Practical considerations in using accelerometers to assess physical activity, sedentary behavior, and sleep

Increasingly, behavioral and epidemiological research uses activity-based measurements (accelerometry) to provide objective estimates of physical activity, sedentary behavior, and sleep in a variety of study designs. As interest in concurrently assessing these domains grows, there are key methodological considerations that influence the choice of monitoring instrument, analysis algorithm, and protocol for measuring these behaviors. The purpose of this review is to summarize evidence-guided information for 7 areas that are of importance in the design and interpretation of studies using actigraphy: (1) choice of cut-points; (2) impact of epoch length; (3) accelerometer placement; (4) duration of monitoring; (5) approaches for distinguishing sleep, nonwear times, and sedentary behavior; (6) role for a sleep and activity diary; and (7) epidemiological applications. Recommendations for future research are outlined and are intended to enhance the appropriate use of accelerometry for assessing physical activity, sedentary behavior, and sleep behaviors in research studies.

Accelerometer adherence and performance in a cohort study of US Hispanic adults

PURPOSE

This study described participant adherence to wearing the accelerometer and accelerometer performance in a cohort study of adults.

METHODS

From 2008 to 2011, 16,415 US Hispanic/Latino adults age 18-74 yr enrolled in the Hispanic Community Health Study/Study of Latinos. Immediately after the baseline visit, participants wore an Actical accelerometer for 1 wk. This study explored correlates of accelerometer participation and adherence, defined as wearing it for at least three of a possible six days for ≥10 h·d. Accelerometer performance was assessed by exploring the number of different values of accelerometer counts per minute for each participant.

RESULTS

Overall, 92.3% (n = 15,153) had at least 1 d with accelerometer data and 77.7% (n = 12,750) were adherent. Both accelerometer participation and adherence were higher among participants who were married or partnered, reported a higher household income, were first-generation immigrants, or reported lower sitting time. Participation was also higher among those with no stair limitations. Adherence was higher among participants who were male, older, employed or retired, not US born, preferred Spanish over English, reported higher work activity or lower recreational activity, and with a lower body mass index. Among the sample that met the adherence definition, the maximum recorded count per minute was 12,000, and there were a total of 5846 different counts per minute. On average, participants had 112.5 different counts per minute over 6 d (median, 106; interquartile range, 91-122). The number of different counts per minute was higher among men, younger ages, normal weight, and those with higher accelerometer-assessed physical activity.

CONCLUSION

Several correlates differed between accelerometer participation and adherence. These characteristics could be targeted in future studies to improve accelerometer wear. The performance of the accelerometer provided insight into creating a more accurate nonwear algorithm.

Maintaining physical activity during head and neck cancer treatment: Results of a pilot controlled trial

BACKGROUND

Concurrent chemoradiotherapy (concurrent CRT) to treat head and neck cancer is associated with significant reductions of weight, mobility, and quality of life (QOL). An intervention focusing on functional exercise may attenuate these losses.

METHODS

We allocated patients to a 14-week functional resistance and walking program designed to maintain physical activity during cancer treatment (MPACT group; n = 11), or to usual care (control group; n = 9). Outcomes were assessed at baseline, and 7 and 14 weeks.

RESULTS

Compared to controls, the MPACT participants had attenuated decline or improvement in several strength, mobility, physical activity, diet, and QOL endpoints. These trends were statistically significant (p < .05) in knee strength, mental health, head and neck QOL, and barriers to exercise.

CONCLUSION

In this pilot study of patients with head and neck cancer undergoing concurrent CRT, MPACT training was feasible and maintained or improved function and QOL, thereby providing the basis for larger future interventions with longer follow-up. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1086-E1096, 2016.

Objective Versus Self-Reported Physical Activity in Overweight and Obese Young Adults

BACKGROUND

To compare moderate-to-vigorous intensity physical activity (MVPA) assessed via questionnaires to an objective measure of MVPA in overweight or obese young adults.

METHODS

MVPA was assessed in 448 [median BMI = 31.2 (Interquartile Range: 28.5-34.3) kg/m2] young adults [median age: 30.9 (Interquartile Range: 27.8-33.7) years]. Measures included the SenseWear Armband (MVPAOBJ), the Paffenbarger Questionnaire (MVPAPAFF), and the Global Physical Activity Questionnaire (GPAQ). The GPAQ was used to compute total MVPA (MVPAGPAQ-TOTAL) and MVPA from transportation and recreation (MVPAGPAQ-REC).

RESULTS

The association between MVPAOBJ and MVPAPAFF was rs = 0.40 (P < .0001). Associations between MVPAOBJ and MVPAGPAQ-TOTAL and MVPAGPAQ-REC were rs = 0.19 and rs = 0.32, respectively (P < .0001). MVPAGPAQ-TOTAL was significantly greater than MVPAOBJ (P < .0001). Median differences in MET-min/week between MVPAOBJ and MVPAPAFF or MVPAGPAQ-REC were not significantly different from zero. There was proportional bias between each self-reported measure of MVPA and MVPAOBJ. There were significant associations between all measures of MVPA and fitness. MVPAOBJ was significantly associated with BMI and percent body fat.

CONCLUSIONS

Objective and self-reported measures of MVPA are weakly to moderately correlated, with substantial differences between measures. MVPAOBJ provided predictive validity with fitness, BMI, and percent body fat. Thus, an objective measure of MVPA may be preferred to self-report in young adults.

Neighbourhood built environment associations with body size in adults: mediating effects of activity and sedentariness in a cross-sectional study of New Zealand adults

BACKGROUND

The aim of this study was to determine the associations between body size and built environment walkability variables, as well as the mediating role of physical activity and sedentary behaviours with body size.

METHODS

Objective environment, body size (body mass index (BMI), waist circumference (WC)), and sedentary time and physical activity data were collected from a random selection of 2033 adults aged 20-65 years living in 48 neighbourhoods across four New Zealand cities. Multilevel regression models were calculated for each comparison between body size outcome and built environment exposure.

RESULTS AND DISCUSSION

Street connectivity and neighborhood destination accessibility were significant predictors of body size (1 SDchange predicted a 1.27 to 1.41 % reduction in BMI and a 1.76 to 2.29 % reduction in WC). Significantrelationships were also observed for streetscape (1 SD change predicted a 1.33 % reduction in BMI) anddwelling density (1 SD change predicted a 1.97 % reduction in BMI). Mediation analyses revealed asignificant mediating effect of physical activity on the relationships between body size and street connectivity and neighbourhood destination accessibility (explaining between 10.4 and 14.6 % of the total effect). No significant mediating effect of sedentary behaviour was found. Findings from this cross-sectional study of a random selection of New Zealand adults are consistent with international research. Findings are limited to individual environment features only; conclusions cannot be drawn about the cumulative and combined effect of individual features on outcomes.

CONCLUSIONS

Built environment features were associated with body size in the expected directions. Objectively-assessed physical activity mediated observed built environment-body size relationships.

Accelerometer determined sedentary behavior and dietary quality among US adults

OBJECTIVE

Scant evidence exists pertaining to objectively measured sedentary time and dietary quality among adults. Therefore, we examined the relationships between sedentary time, physical activity, and dietary quality.

METHODS

Cross-sectional analyses of a 4,910 US adults from two cycles (2003-2006) of the National Health and Nutrition Examination Survey. The primary independent variables were sedentary time and physical activity (continuous and categorical), while the outcomes were overall dietary quality (Healthy Eating Index (HEI) 2010), fruit and vegetable scores, and empty caloric intake (kcal).

RESULTS

Multivariable analyses revealed that a 1min increase in daily sedentary behavior was associated with a 0.2kcal decrease in empty calories (-0.18, 95% CI=-0.34, -0.03); however, sedentary time was not significantly related to overall dietary quality (HEI) and fruit and vegetable intake. In comparison, a 1min increase in daily moderate-to-vigorous intensity physical activity was related to a 0.1 higher HEI score (0.08, 95% CI=0.04, 0.11), a 0.01 higher fruit score (0.01, 95% CI=0.01, 0.02), and conversely a 1.3kcal decrease in empty calories (-1.35, 95% CI=-2.01, -0.69). In addition, meeting physical activity guidelines was associated with a 2.8 point higher HEI score (2.82, 95% CI=1.40, 4.25), a 0.5 point higher fruit score (0.51, 95% CI=0.31-0.71), and 37.4 fewer empty calories (-37.43, 95% CI=-64.86, -9.10).

CONCLUSIONS

Physical activity is significantly related to better overall dietary quality, while sedentary behavior is not. Findings suggest the need to promote physical activity and encourage adherence to dietary guidelines jointly, whereas sedentary behavior and overall dietary quality might need to be targeted independently.

Apps for IMproving FITness and Increasing Physical Activity Among Young People: The AIMFIT Pragmatic Randomized Controlled Trial

Background

Given the global prevalence of insufficient physical activity (PA), effective interventions that attenuate age-related decline in PA levels are needed. Mobile phone interventions that positively affect health (mHealth) show promise; however, their impact on PA levels and fitness in young people is unclear and little is known about what makes a good mHealth app.

Objective

The aim was to determine the effects of two commercially available smartphone apps (Zombies, Run and Get Running) on cardiorespiratory fitness and PA levels in insufficiently active healthy young people. A second aim was to identify the features of the app design that may contribute to improved fitness and PA levels.

Methods

Apps for IMproving FITness (AIMFIT) was a 3-arm, parallel, randomized controlled trial conducted in Auckland, New Zealand. Participants were recruited through advertisements in electronic mailing lists, local newspapers, flyers posted in community locations, and presentations at schools. Eligible young people aged 14-17 years were allocated at random to 1 of 3 conditions: (1) use of an immersive app (Zombies, Run), (2) use of a nonimmersive app (Get Running), or (3) usual behavior (control). Both smartphone apps consisted of a fully automated 8-week training program designed to improve fitness and ability to run 5 km; however, the immersive app featured a game-themed design and narrative. Intention-to-treat analysis was performed using data collected face-to-face at baseline and 8 weeks, and all regression models were adjusted for baseline outcome value and gender. The primary outcome was cardiorespiratory fitness, objectively assessed as time to complete the 1-mile run/walk test at 8 weeks. Secondary outcomes were PA levels (accelerometry and self-reported), enjoyment, psychological need satisfaction, self-efficacy, and acceptability and usability of the apps.

Results

A total of 51 participants were randomized to the immersive app intervention (n=17), nonimmersive app intervention (n=16), or the control group (n=18). The mean age of participants was 15.7 (SD 1.2) years; participants were mostly NZ Europeans (61%, 31/51) and 57% (29/51) were female. Overall retention rate was 96% (49/51). There was no significant intervention effect on the primary outcome using either of the apps. Compared to the control, time to complete the fitness test was –28.4 seconds shorter (95% CI –66.5 to 9.82, P=.20) for the immersive app group and –24.7 seconds (95% CI –63.5 to 14.2, P=.32) for the nonimmersive app group. No significant intervention effects were found for secondary outcomes.

Conclusions

Although apps have the ability to increase reach at a low cost, our pragmatic approach using readily available commercial apps as a stand-alone instrument did not have a significant effect on fitness. However, interest in future use of PA apps is promising and highlights a potentially important role of these tools in a multifaceted approach to increase fitness, promote PA, and consequently reduce the adverse health outcomes associated with insufficient activity.

Trial Registration

Australian New Zealand Clinical Trials Registry: ACTRN12613001030763; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12613001030763 (Archived by WebCite at http://www.webcitation.org/6aasfJVTJ).

Feasibility and preliminary efficacy of a physical activity counseling intervention using Fitbit in people with knee osteoarthritis: the TRACK-OA study protocol

Background

Physical activity (PA) reduces pain and improves functioning in people with knee osteoarthritis (OA), but few people with the condition meet recommended PA guidelines. Successful intervention strategies to increase PA include goal setting, action planning, self-monitoring, and follow-up feedback from a healthcare professional. Recently developed consumer wearable activity trackers allow users to set activity goals, self-monitor daily goal-progress, and provide feedback on goal attainment. It is hypothesized that a multi-component physiotherapist-led intervention that includes a short (40-min) education module, guided goal-setting and action planning, the use of a wristband activity tracker, and weekly follow-up phone calls will lead to increased PA outcomes.

Methods/design

Thirty-six participants will be recruited from the community for a two-group pilot randomized controlled trial with a stepped-wedge design using an intention-to-treat analysis. Computer-generated block randomization will be performed using varying block sizes and a 1:1 allocation ratio. The 4-week intervention will be delivered immediately (immediate-intervention group) or after a 5-week delay (delayed-intervention group). Outcome measures of pain and disability (Knee Injury and OA Outcome Score), disease self-management ability (Partners in Health Scale), and objective bouted moderate-to-vigorous PA and sedentary time (BodyMedia SenseWear Mini Armband) will be collected at baseline (week 0) and two follow-ups (weeks 5 and 10), for a total study duration of 11 weeks. Feasibility data relating to process, resource, management, and scientific elements of the trial will be collected. Outcome measure and feasibility data will be summarized, and an estimate of intervention efficacy will be obtained by regression model with planned comparisons. The trial began recruiting in February 2015. To date, 34 subjects have been recruited.

Discussion

This study will evaluate the feasibility and preliminary efficacy of a novel intervention to promote PA in people living with knee OA. The results will provide valuable information to inform a larger randomized trial to assess intervention effectiveness.

Trial registration

ClinicalTrials.gov Identifier: NCT02313506 (registration date 8 December 2014). First participant randomized 20 February 2015.

Accelerometer-based Physical Activity Monitoring in Patients with Knee Osteoarthritis: Objective and Ambulatory Assessment of Actual Physical Activity During Daily Life Circumstances

Background:

It is important to assess physical activity objectively during daily life circumstances, to understand the association between physical activity and diseases and to determine the effectiveness of interventions. Accelerometer-based physical activity monitoring seems a promising method and could potentially capture all four FITT (i.e. Frequency, Intensity, Time, Type) components of physical activity considered by the World Health Organization (WHO).

Aim:

To assess the four FITT components of physical activity with an accelerometer during daily life circumstances and compare with self-reported levels of physical activity in patients with knee osteoarthritis (OA) and a healthy control group.

Methods:

Patients (n=30) with end-stage knee OA and age-matched healthy subjects (n=30) were measured. An ambulant tri-axial accelerometer was placed onto the lateral side of the upper leg. Physical activity was measured during four consecutive days. Using algorithm-based peak detection methods in Matlab, parameters covering the four FITT components were assessed. Self-reported physical activity was assessed using the Short questionnaire to assess health enhancing physical activity (SQUASH).

Results:

Knee OA patients demonstrated fewer walking bouts (154 ±79 versus 215 ±65 resp.; p=0.002), step counts (4402 ±2960 steps/day versus 6943 ±2581 steps/day; p=0.001) and sit-to-stand (STS) transfers (37 ±14 versus 44 ±12; p=0.031) compared to controls. Knee OA patients demonstrated more time sitting (65 ±15% versus 57 ±10% resp.; p=0.029), less time walking (8 ±4% versus 11 ±4% resp.; p=0.014) and lower walking cadence (87 ±11steps/min versus 99 ± 8steps/min resp.; p<0.001). Accelerometer-based parameters of physical activity were moderately-strong (Pearsons’s r= 0.28-0.49) correlated to self-reported SQUASH scores.

Conclusion:

A single ambulant accelerometer-based physical activity monitor feasibly captures the four FITT components of physical activity and provides more insight into the actual physical activity behavior and limitations of knee OA patients in their daily life.

Modelling a response as a function of high-frequency count data: The association between physical activity and fat mass

Accelerometers are widely used in health sciences, ecology and other application areas. They quantify the intensity of physical activity as counts per epoch over a given period of time. Currently, health scientists use very lossy summaries of the accelerometer time series, some of which are based on coarse discretisation of activity levels, and make certain implicit assumptions, including linear or constant effects of physical activity. We propose the histogram as a functional summary for achieving a near lossless dimension reduction, comparability between individual time series and easy interpretability. Using the histogram as a functional summary avoids registration of accelerometer counts in time. In our novel method, a scalar response is regressed on additive multi-dimensional functional predictors, including the histogram of the high-frequency counts, and additive non-linear predictors for other continuous covariates. The method improves on the current state-of-the art, as it can deal with high-frequency time series of different lengths and missing values and yields a flexible way to model the physical activity effect with fewer assumptions. It also allows the commonly made modelling assumptions to be tested. We investigate the relationship between the response fat mass and physical activity measured by accelerometer, in data from the Avon Longitudinal Study of Parents and Children. Our method allows testing of whether the effect of physical activity varies over its intensity by gender, by time of day or by day of the week. We show that meaningful interpretation requires careful treatment of identifiability constraints in the light of the sum-to-one property of a histogram. We find that the (not necessarily causal) effect of physical activity on kg fat mass is not linear and not constant over the activity intensity.

Clinical Interest of Ambulatory Assessment of Physical Activity and Walking Capacity in Peripheral Artery Disease

The purpose of the present review was to provide, for the first time, a comprehensive analysis and synthesis of the available studies that highlighted the clinical interest of the ambulatory assessment of either physical activity (PA) or walking capacity in patients with lower extremity peripheral artery disease (PAD). We identified 96 related articles published up to March 2015 through a computer-assisted search of the MEDLINE, EMBASE, and Web of Science databases. Ambulatory-measured PA or related energy expenditure (EE) in PAD patients was performed in 87 of the 96 included studies. The main clinical interests of these measurements were (a) the assessment of PA/EE pattern; (b) the characterization of walking pattern; and (c) the control of training load during home-based walking programs. Ambulatory-measured walking capacity was performed in the remaining studies, using either Global Positioning System receivers or the Peripheral Arterial Disease Holter Control device. Highlighted clinical interests were (a) the assessment of community-based walking capacity; (b) the use of new outcomes to characterize walking capacity, besides the conventional absolute claudication distance; and (c) the association with the patient's self-perception of walking capacity. This review also provides for the clinicians step-by-step recommendations to specifically assess PA or walking capacity in PAD patients.

Influence of habitual physical activity on gastric emptying in healthy males and relationships with body composition and energy expenditure

Although a number of studies have examined the role of gastric emptying (GE) in obesity, the influences of habitual physical activity level, body composition and energy expenditure (EE) on GE have received very little consideration. In the present study, we compared GE in active and inactive males, and characterised relationships with body composition (fat mass and fat-free mass) and EE. A total of forty-four males (active n 22, inactive n 22; BMI 21-36 kg/m2; percentage of fat mass 9-42%) were studied, with GE of a standardised (1676 kJ) pancake meal being assessed by the [13C]octanoic acid breath test, body composition by air displacement plethysmography, RMR by indirect calorimetry, and activity EE (AEE) by accelerometry. The results showed that GE was faster in active compared with inactive males (mean half-time (t 1/2): active 157 (sd 18) and inactive 179 (sd 21) min, P< 0.001). When data from both groups were pooled, GE t 1/2 was associated with percentage of fat mass (r 0.39, P< 0.01) and AEE (r - 0.46, P< 0.01). After controlling for habitual physical activity status, the association between AEE and GE remained, but not that for percentage of fat mass and GE. BMI and RMR were not associated with GE. In summary, faster GE is considered to be a marker of a habitually active lifestyle in males, and is associated with a higher AEE level and a lower percentage of fat mass. The possibility that GE contributes to a gross physiological regulation (or dysregulation) of food intake with physical activity level deserves further investigation.

Smartphone apps to improve fitness and increase physical activity among young people: protocol of the Apps for IMproving FITness (AIMFIT) randomized controlled trial

Background

Physical activity is a modifiable behavior related to many preventable non-communicable diseases. There is an age-related decline in physical activity levels in young people, which tracks into adulthood. Common interactive technologies such as smartphones, particularly employing immersive features, may enhance the appeal and delivery of interventions to increase levels of physical activity in young people. The primary aim of the Apps for IMproving FITness (AIMFIT) trial is to evaluate the effectiveness of two popular “off-the-shelf” smartphone apps for improving cardiorespiratory fitness in young people.

Methods/Design

A three-arm, parallel, randomized controlled trial will be conducted in Auckland, New Zealand. Fifty-one eligible young people aged 14–17 years will be randomized to one of three conditions: 1) use of an immersive smartphone app, 2) use of a non-immersive app, or 3) usual behavior (control). Both smartphone apps consist of an eight-week training program designed to improve fitness and ability to run 5 km, however, the immersive app features a game-themed design and adds a narrative. Data are collected at baseline and 8 weeks. The primary outcome is cardiorespiratory fitness, assessed as time to complete the one mile run/walk test at 8 weeks. Secondary outcomes are physical activity levels, self-efficacy, enjoyment, psychological need satisfaction, and acceptability and usability of the apps. Analysis using intention to treat principles will be performed using regression models.

Discussion

Despite the proliferation of commercially available smartphone applications, there is a dearth of empirical evidence to support their effectiveness on the targeted health behavior. This pragmatic study will determine the effectiveness of two popular “off-the-shelf” apps as a stand-alone instrument for improving fitness and physical activity among young people. Adherence to app use will not be closely controlled; however, random allocation of participants, a heterogeneous group, and data analysis using intention to treat principles provide internal and external validity to the study. The primary outcome will be objectively assessed with a valid and reliable field-based test, as well as the secondary outcome of physical activity, via accelerometry. If effective, such applications could be used alongside existing interventions to promote fitness and physical activity in this population.

Trial Registration

Australian New Zealand Clinical Trials Registry: ACTRN12613001030763. Registered 16 September 2013.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1968-y) contains supplementary material, which is available to authorized users.

Impact of a brief intervention on self-regulation, self-efficacy and physical activity in older adults with type 2 diabetes

Despite evidence of the benefits of physical activity, most individuals with type 2 diabetes do not meet physical activity recommendations. The purpose of this study was to test the efficacy of a brief intervention targeting self-efficacy and self-regulation to increase physical activity in older adults with type 2 diabetes. Older adults (Mage = 61.8 ± 6.4) with type 2 diabetes or metabolic syndrome were randomized into a titrated physical activity intervention (n = 58) or an online health education course (n = 58). The intervention included walking exercise and theory-based group workshops. Self-efficacy, self-regulation and physical activity were assessed at baseline, post-intervention, and a follow-up. Results indicated a group by time effect for self-regulation [F(2,88) = 14.021, p < .001, η (2) = .24] and self-efficacy [F(12,77) = 2.322, p < .05, η (2) = .266] with increases in the intervention group. The intervention resulted in short-term increases in physical activity (d = .76, p < .01), which were partially maintained at the 6-month follow-up (d = .35, p < .01). The intervention increased short-term physical activity but was not successful at maintaining increases in physical activity. Similar intervention effects were observed in self-efficacy and self-regulation. Future research warrants adjusting intervention strategies to increase long-term change.

Pedometers Affect Changes in Lower-Extremity Physical Function During a Square-Stepping Exercise Program in Older Japanese Adults

BACKGROUND AND PURPOSE

Pedometers are often used as motivational tools to increase physical activity. Hence, providing a pedometer during an exercise intervention may enhance the benefit of exercise on lower-extremity physical function (LEPF) by maintaining or increasing daily physical activity. The purpose of this study was to compare the effect on LEPF between an exercise intervention with and without the use of a pedometer.

METHODS

The subjects of this study were 68 community-dwelling older adults (mean age: 70.0 ± 3.6 years) in Kasama City, rural Japan. All subjects participated in a fall-prevention exercise program called square-stepping exercise (SSE) conducted once a week for 11 weeks. Participants were allocated to 2 groups: SSE with pedometer group (n = 34) and SSE without pedometer group (n = 34). We matched the participants of both groups by their standardized score of physical function tests. To ascertain the LEPF benefits induced by the exercise intervention, we measured 5 physical function tests: single-leg balance with eyes open, 5-repetition sit-to-stand, timed up and go, 5-m habitual walk, and choice stepping reaction time. We used a 2-way analysis of variance to confirm the interaction between the 2 groups.

RESULTS

Significant group-by-time interactions were observed on timed up and go (P < .01) and 5-m habitual walk (P = .02); participants in the SSE with pedometer group enhanced their physical function more than the SSE without pedometer group participants.

CONCLUSIONS

This study suggests that providing a pedometer during an exercise intervention is an effective addition to an exercise program to improve LEPF.