Objective measurement of physical activity and sedentary behaviour: review with new data

Objective methods are being used increasingly for the quantification of the amount of physical activity, intensity of physical activity and amount of sedentary behaviour in children. The accelerometer is currently the objective method of choice. In this review we address the advantages of objective measurement compared with more traditional subjective methods, notably the avoidance of bias, greater confidence in the amount of activity and sedentary behaviour measured, and improved ability to relate variation in physical activity and sedentary behaviour to variation in health outcomes. We also consider unresolved practical issues in paediatric accelerometry by critically reviewing the existing evidence and by providing new evidence.

Monitoring of Physical Activity in Young Children: How Much Is Enough?

There is limited evidence on how much and on which days accelerometry monitoring should be performed to obtain a representative measurement of physical activity (PA) in young children. We measured 76 children (40 M and 36 F, mean age 5.6 years ([SD ± 0.4]) on 7 days using Actigraph accelerometers. Mean daily PA was expressed in counts per min (cpm). Reliability increased as the number of days and hours of monitoring increased, but only to 10 hr per day. At 7 days of monitoring for 10 hr per day, reliability was 80% (95% CI [70%, 86%]). The number of days was more important to reliability than the number of hours. The inclusion or exclusion of weekend days made relatively little difference. A monitoring period of 7 days for 10 hr per day produced the highest reliability. Surprisingly short monitoring periods may provide adequate reliability in young children.

Validity, practical utility and reliability of Actigraph accelerometry for the measurement of habitual physical activity in dogs

OBJECTIVES

To test the validity, practical utility, and reliability of the Actigraph GT3-X accelerometer for measurement of habitual physical activity in pet dogs.

METHODS

In the validation study, 30 dogs wore the accelerometer for 1 day while being filmed. Accelerometer and film were synchronised and 10-minute periods of the filmed records were extracted with dogs in continuous periods of sedentary behaviour, light intensity physical activity indoors, light to moderate intensity physical activity outdoors and vigorous physical activity outdoors. For the practical utility and reliability studies, 20 dogs wore the GT3-X accelerometers for 1 week: practical utility was quantified as data loss and was also assessed by owner questionnaire; reliability was determined by 2 to 7 days of monitoring using the Spearman-Brown prophecy formula.

RESULTS

In the validation study, accelerometry output differed significantly between activity intensities (Friedman test, P<0·01). In the practical utility study, no data were lost from any dogs and dog owners reported that accelerometry was well tolerated. Reliability of accelerometry output was high: for 3 days of wear, it was 91% [95% confidence interval (CI) 82 to 96] and for 7 days of wear, it was 94% (CI 88 to 97).

CLINICAL SIGNIFICANCE

The GT3-X accelerometer is valid, practical and reliable for the measurement of habitual physical activity in dogs.

Carers' perspectives of a weight loss intervention for adults with intellectual disabilities and obesity: a qualitative study

BACKGROUND

To date, no studies have explored the role of carers in supporting adults with intellectual disabilities (ID) and obesity during a weight loss intervention. The present study explored perceptions of carers supporting adults with ID, as they participated in a 6-month multi-component weight loss intervention (TAKE 5).

METHODS

Semi-structured interviews were used to explore the experiences of 24 carers. The transcripts were analysed qualitatively using thematic analysis.

RESULTS

Three themes emerged from the analysis: carers' perceptions of participants' health; barriers and facilitators to weight loss; and carers' perceptions of the weight loss intervention. Data analysis showed similarities between the experiences reported by the carers who supported participants who lost weight and participants who did not. Lack of sufficient support from people from the internal and external environment of individuals with ID and poor communication among carers, were identified as being barriers to change. The need for accessible resources tailored to aid weight loss among adults with ID was also highlighted.

CONCLUSION

This study identified specific facilitators and barriers experienced by carers during the process of supporting obese adults with ID to lose weight. Future research could utilise these findings to inform appropriate and effective weight management interventions for individuals with ID.

Agreement of accelerometer and a physical activity questionnaire in adults with intellectual disabilities

PURPOSE

To assess the level of agreement between accelerometer and proxy-respondent questionnaire measurement of the physical activity levels of adults with intellectual disabilities.

METHODS

In Glasgow, U.K., from May to September 2009, the main carer of participants with intellectual disabilities was asked to complete the International Physical Activity Questionnaire-Short Version, detailing the participants' regular physical activity levels. Participants were also invited to wear an ActiGraph GT1M accelerometer for seven consecutive days, during all waking hours. The level of agreement from the two measurements was compared using the Bland-Altman method.

RESULTS

There is limited agreement between physical activity and sedentary behavior measured with accelerometer and proxy-respondent questionnaire. The 95% limits of agreement for both moderate activity and sedentary activity were -44.48 to 34.20 min per day and -8.41 to 6.79 h per day, respectively. As physical activity increased above 10 min per day, the agreement between the accelerometer and International Physical Activity Questionnaire-Short Version data decreased further.

CONCLUSION

It remains uncertain whether questionnaire methods have sufficient reliability for use in surveillance of physical activity levels of adults with intellectual disabilities.

Children, parents and pets exercising together (CPET): exploratory randomised controlled trial

BACKGROUND

Levels of physical activity (PA) in UK children are much lower than recommended and novel approaches to its promotion are needed. The Children, Parents and Pets Exercising Together (CPET) study is the first exploratory randomised controlled trial (RCT) to develop and evaluate an intervention aimed at dog-based PA promotion in families. CPET aimed to assess the feasibility, acceptability and potential efficacy of a theory-driven, family-based, dog walking intervention for 9-11 year olds.

METHODS

Twenty-eight families were allocated randomly to either receive a 10-week dog based PA intervention or to a control group. Families in the intervention group were motivated and supported to increase the frequency, intensity and duration of dog walking using a number of behaviour change techniques. Parents in the intervention group were asked to complete a short study exit questionnaire. In addition, focus groups with parents and children in the intervention group, and with key stakeholders were undertaken. The primary outcome measure was 10 week change in total volume of PA using the mean accelerometer count per minute (cpm). Intervention and control groups were compared using analysis of covariance. Analysis was performed on an intention to treat basis.

RESULTS

Twenty five families were retained at follow up (89%) and 97% of all outcome data were collected at baseline and follow up. Thirteen of 14 (93%) intervention group parents available at follow up completed the study exit questionnaire and noted that study outcome measures were acceptable. There was a mean difference in child total volume of PA of 27 cpm (95% CI -70, 123) and -3 cpm (95% CI -60, 54) for intervention and control group children, respectively. This was not statistically significant. Approximately 21% of dog walking time for parents and 39% of dog walking time for children was moderate-vigorous PA.

CONCLUSIONS

The acceptability of the CPET intervention and outcome measures was high. Using pet dogs as the agent of lifestyle change in PA interventions in children and their parents is both feasible and acceptable, but did not result in a significant increase in child PA in this exploratory trial.

TRIAL REGISTRATION

ISRCTN85939423.

Calibration and Cross-Validation of the ActiGraph wGT3X+ Accelerometer for the Estimation of Physical Activity Intensity in Children with Intellectual Disabilities

Background

Valid objective measurement is integral to increasing our understanding of physical activity and sedentary behaviours. However, no population-specific cut points have been calibrated for children with intellectual disabilities. Therefore, this study aimed to calibrate and cross-validate the first population-specific accelerometer intensity cut points for children with intellectual disabilities.

Methods

Fifty children with intellectual disabilities were randomly assigned to the calibration (n = 36; boys = 28, 9.53±1.08yrs) or cross-validation (n = 14; boys = 9, 9.57±1.16yrs) group. Participants completed a semi-structured school-based activity session, which included various activities ranging from sedentary to vigorous intensity. Direct observation (SOFIT tool) was used to calibrate the ActiGraph wGT3X+, which participants wore on the right hip. Receiver Operating Characteristic curve analyses determined the optimal cut points for sedentary, moderate, and vigorous intensity activity for the vertical axis and vector magnitude. Classification agreement was investigated using sensitivity, specificity, total agreement, and Cohen’s kappa scores against the criterion measure of SOFIT.

Results

The optimal (AUC = .87−.94) vertical axis cut points (cpm) were ≤507 (sedentary), 1008−2300 (moderate), and ≥2301 (vigorous), which demonstrated high sensitivity (81−88%) and specificity (81−85%). The optimal (AUC = .86−.92) vector magnitude cut points (cpm) of ≤1863 (sedentary), 2610−4214 (moderate), and ≥4215 (vigorous) demonstrated comparable, albeit marginally lower, accuracy than the vertical axis cut points (sensitivity = 80−86%; specificity = 77−82%). Classification agreement ranged from moderate to almost perfect (κ = .51−.85) with high sensitivity and specificity, and confirmed the trend that accuracy increased with intensity, and vertical axis cut points provide higher classification agreement than vector magnitude cut points.

Conclusions

This study provides the first valid methods of interpreting accelerometer output in children with intellectual disabilities. The calibrated physical activity cut points are notably higher than existing cut points, thus raising questions on the validity of previous low physical activity estimates in children with intellectual disabilities that were based on typically developing cut points.

Accelerometer use during field-based physical activity research in children and adolescents with intellectual disabilities: a systematic review

Many methodological questions and issues surround the use of accelerometers as a measure of physical activity during field-based research. To ensure overall research quality and the accuracy of results, methodological decisions should be based on study research questions. This paper aims to systematically review accelerometer use during field-based research in children and adolescents with intellectual disabilities. Medline, Embase, Cochrane Library, Web of Knowledge, PsycINFO, PubMed, and a thesis database (up to May 2013) were searched to identify relevant articles. Articles which used accelerometry-based monitors, quantified activity levels, and included ambulatory children and adolescents (≤ 18 years) with intellectual disabilities were included. Based on best practice guidelines, a form was developed to extract data based on 17 research components of accelerometer use. The search identified 429 articles. Ten full-text articles met the criteria and were included in the review. Many shortcomings in accelerometer use were identified, with the percentage of review criteria met ranging from 12% to 47%. Various methods of accelerometer use were reported, with most use decisions not based on population-specific research. However, a lack of measurement research, e.g., calibration/validation, for children and adolescents with intellectual disabilities is limiting the ability of field-based researchers to make to the most appropriate accelerometer use decisions. The methods of accelerometer use employed can have significant effects on the quality and validity of results produced, which researchers should be more aware of. To allow informed use decisions, there should be a greater focus on measurement research related to children and adolescents with intellectual disabilities.

Feasibility and validity of the ActiGraph GT3X accelerometer in measuring physical activity of Malawian toddlers

AIM

To test the feasibility and validity of the ActiGraph GT3X accelerometer in measuring physical activity of rural Malawian toddlers.

METHODS

Fifty-six children aged 16.0-18.5 months wore the accelerometer on their right hip for 7 days. We analysed days with a minimum of 600 min of wear time, excluding night time and periods when the unit registered zero for 20 consecutive minutes. The first and last days were excluded as they were incomplete. Accelerometer counts were compared with coded free play video recordings to define median accelerometer counts for sedentary, light, moderate and vigorous activity. Count cut points were defined for moderate to vigorous physical activity, with predictive validity assessed using a second set of video recordings.

RESULTS

Median wear time was 797 min/day, with 79% of participants completing at least four eligible days. Accelerometer counts were significantly higher for observed moderate to vigorous physical activity, than lighter activity, with cut points of 208 counts/15 sec for vector magnitude and 35 counts/15 sec for vertical axis, showing sensitivity of 94.2% and 84.1% and specificity of 90.9% and 84.6%, respectively.

CONCLUSION

The accelerometer proved a feasible and valid method of assessing physical activity among Malawian toddlers.

An Investigation of Surface EMG Shorts-Derived Training Load during Treadmill Running

The purpose of this study was two-fold: (1) to determine the sensitivity of the sEMG shorts-derived training load (sEMG-TL) during different running speeds; and (2) to investigate the relationship between the oxygen consumption, heart rate (HR), rating of perceived exertion (RPE), accelerometry-based PlayerLoadTM (PL), and sEMG-TL during a running maximum oxygen uptake (V˙O2max) test. The study investigated ten healthy participants. On day one, participants performed a three-speed treadmill test at 8, 10, and 12 km·h-1 for 2 min at each speed. On day two, participants performed a V˙O2max test. Analysis of variance found significant differences in sEMG-TL at all three speeds (p < 0.05). A significantly weak positive relationship between sEMG-TL and %V˙O2max (r = 0.31, p < 0.05) was established, while significantly strong relationships for 8 out of 10 participants at the individual level (r = 0.72-0.97, p < 0.05) were found. Meanwhile, the accelerometry PL was not significantly related to %V˙O2max (p > 0.05) and only demonstrated significant correlations in 3 out of 10 participants at the individual level. Therefore, the sEMG shorts-derived training load was sensitive in detecting a work rate difference of at least 2 km·h-1. sEMG-TL may be an acceptable metric for the measurement of internal loads and could potentially be used as a surrogate for oxygen consumption.

Feasibility of a laboratory-based protocol for measuring energy expenditure and accelerometer calibration in adults with intellectual disabilities

Adults with intellectual disabilities experience numerous health inequalities. Targeting unhealthy lifestyle behaviours, such as high levels of sedentary behaviour and overweight/obesity, is a priority area for improving the health and adults with intellectual disabilities and reducing inequalities. Energy expenditure is a fundamental component of numerous health behaviours and an essential component of various free-living behaviour measurements, e.g. accelerometry. However, little is known about energy expenditure in adults with intellectual disabilities and no population-specific accelerometer data interpretation methods have been calibrated. The limited research in this area suggests that adults with intellectual disabilities have a higher energy expenditure, which requires further exploration, and could have significant impacts of device calibration. However, due to the complex methods required for measuring energy expenditure, it is essential to first evaluate feasibility and develop an effective protocol. This study aims to test the feasibility of a laboratory-based protocol to enable the measurement of energy expenditure and accelerometer calibration in adults with intellectual disabilities.We aimed to recruit ten adults (≥ 18 years) with intellectual disabilities. The protocol involved a total of nine sedentary, stationary, and physical activities, e.g. sitting, lying down, standing, and treadmill walking. Each activity was for 5 min, with one 10 min lying down activity to measure resting energy expenditure. Breath by breath respiratory gas exchange and accelerometry (ActiGraph and ActivPAL) were measured during each activity. Feasibility was assessed descriptively using recruitment and outcome measurement completion rates, and participant/stakeholder feedback.Ten adults (N = 7 female) with intellectual disabilities participated in this study. The recruitment rate was 50% and 90% completed the protocol and all outcome measures. Therefore, the recruitment strategy and protocol are feasible.This study addresses a significant gap in our knowledge relating to exercise laboratory-based research for adults with intellectual disabilities The findings from this study provide essential data that can be used to inform the development of future protocols to measure energy expenditure and for accelerometer calibration in adults with intellectual disabilities.

Feasibility of a laboratory-based accelerometer calibration protocol for children with intellectual disabilities

BACKGROUND

Accelerometry has not been calibrated for the estimation of physical activity in children with intellectual disabilities (ID), raising questions regarding the validity of interpreting accelerometer data in this population. Various protocols and criterion measures have been used in calibration studies involving typically developing (TD) children; however, the suitability of these activities and measures for children with ID is unknown. Therefore, this study aimed to test the feasibility of a laboratory-based calibration protocol for children with ID. Specifically, the feasibility of activities, measurements, and recruitment was investigated.

METHODS

Five children with mild to moderate ID (10.20 ± .98 years) and a comparative sample of five TD children (12.40 ± .01 years) participated in this study. Participants performed a free-living and treadmill-based activity protocol during two laboratory-based sessions. Activities were performed for 5 min and ranged from sedentary to vigorous intensity. Treadmill activities ranged from 3 to 8 km/h, and free-living activities included watching a DVD, passing a football, and jumping jacks. Resting energy expenditure was measured, and a graded exercise test was used to assess cardiorespiratory fitness. Breath-by-breath respiratory gas exchange and accelerometry were continually measured during all activities. Feasibility was assessed using observations, activity completion rates, and respiratory data.

RESULTS

All TD participants and one participant with ID completed the protocol. The physical demands of the treadmill activities affected the completion rate for participants with ID. No participant met the maximal criteria for the graded exercise test or attained a steady state during the resting measurements. Limitations were identified with the usability of respiratory gas exchange equipment and the validity of measurements. The school-based recruitment strategy was not effective, with a participation rate of 6 %. A significant (z = 13.21, p < .0001) difference in the relationship of [Formula: see text] and accelerometry was identified between ID and TD participants.

CONCLUSIONS

Due to issues with the usability and validity of breath-by-breath respiratory gas exchange and recruitment, a laboratory-based calibration protocol is currently not feasible for children with ID. An alternative field-based protocol with a non-invasive criterion measure should be considered for future studies.

Graduate prospects explain undergraduate program standing in university league sports science tables

UK university undergraduate programs are compared by independent subject-specific rankings (Complete, Guardian, and Times), based on data from the National Student Survey, Higher Education Statistics Agency, Universities and Colleges Admissions Service, Research Excellence Framework, and the universities. The sports and exercise science program at the University of Glasgow has steadily risen to currently rank as the top UK program. This investigation aimed to identify the underlying factors that explain this. Therefore, we obtained underlying scores for entry standard, student satisfaction, research foundation, graduate prospects, staff-to-student ratio, expenditure/student, continuation, program support to students, and teaching quality from the ranking providers for years 2010-2024, and statistically modeled which factors significantly affected the rankings. We found that entry standards and graduate prospects strongly correlated significantly with ranking results. Principal component analysis indicated that a model of graduate prospects and entry standards explained 66.2% of the variance in ranking results. Multiple linear regression with all underlying factors included in the model indicated they explained 78% (R2 = 0.78) of the total variance, while stepwise elimination of insignificant factors identified graduate prospects as the sole factor that significantly affected outcome by explaining 71% (R2 = 0.71) of the variance. Therefore, the primary predictor of ranking success in UK university league tables for sports science is graduates' professional success (graduate prospects).NEW & NOTEWORTHY University rankings are used by applicants and stakeholders to judge programs, including undergraduate studies. In the rankings, undergraduate UK programs are compared and contrasted against each other based on how they score for criteria that affect student life and future prospects. Here, we determined the relative influence of those criteria and found that graduate prospects, how students professionally benefit from their study after graduation, is the factor that matters most for the ranking results.