V. Penpraze

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.

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.

Associations between obesity and physical activity in dogs: a preliminary investigation

OBJECTIVES To assess whether obesity has any association with objectively measured physical activity levels in dogs. METHODS Thirty-nine dogs wore Actigraph GT3X accelerometers (Actigraph) for 7 consecutive days. Each dog was classified as ideal weight, overweight or obese using the 5-point body condition scoring system. Total volume of physical activity and time spent in sedentary behaviour, light-moderate intensity physical activity and vigorous intensity physical activity were compared between body condition categories. RESULTS Valid accelerometry data were returned for 35 of 39 dogs recruited. Eighteen dogs were classed as ideal weight, 9 as overweight and the remaining 8 as obese. All dogs spent a significant proportion of the day sedentary and obese dogs spent significantly less time in vigorous intensity physical activity than ideal weight dogs (7 ±3 minute/day versus 21 ±15 minute/day, P=0·01). CLINICAL SIGNIFICANCE Obesity is associated with lower vigorous intensity physical activity in dogs, as is also thought to occur in humans. These preliminary findings will help inform a future, larger study and may also improve our understanding of the associations between obesity and physical activity in dogs.

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.

A 6-month observational study of changes in objectively measured physical activity during weight loss in dogs

OBJECTIVES To evaluate long-term changes in physical activity and sedentary behaviour during weight loss in dogs. METHODS Sixteen overweight and obese dogs undergoing a 6-month calorie-controlled weight-loss programme wore Actigraph GT3X accelerometers (Actigraph, FL) for three consecutive days each month for the duration of the programme. Total volume of physical activity and time spent in sedentary behaviour, light-moderate intensity physical activity and vigorous intensity physical activity were extracted from the accelerometer data and compared from baseline to month 6. RESULTS Valid accelerometry data were returned for 14 of 16 dogs. Mean percentage weight loss over 6 months was 15% of initial bodyweight. There was no marked increase in any of the physical activity outcomes or reduction in sedentary behaviour. CLINICAL SIGNIFICANCE Substantial weight loss was not associated with a spontaneous increase in physical activity or reduction in sedentary behaviour. Although the dogs in this study lost a substantial amount of bodyweight without a measured increase in physical activity, dog owners should still be encouraged to facilitate increased physical activity in their dogs owing to the wide range of benefits associated with physical activity other than weight loss.

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

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

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.

Correlates of objectively measured physical activity in dogs.

To increase physical activity (PA) levels in dogs and to better evaluate their energy requirements, there is a need to understand which factors or correlates are associated with PA and/or sedentary behaviour. Improving our understanding of these correlates also has implications for prescribed energy requirements in dogs. PA was measured using accelerometry in 62 dogs from two common breeds (Labrador retrievers and Cocker spaniels). Five potential correlates (age, sex, breed, neuter status, body condition score) were tested for associations with total volume of PA, light-moderate intensity PA, vigorous intensity PA and sedentary behaviour. Age and breed were associated with total volume of PA, light-moderate intensity PA and sedentary behaviour in the final models. Age was associated with vigorous intensity PA. The final models explained 60%, 40%, 63% and 44% of variance in total volume of PA, light-moderate intensity PA, vigorous intensity PA and sedentary behaviour, respectively. These results should improve understanding of the variation in energy requirements of dogs, as well as the development of age and breed-specific diets and the prevention and treatment of canine obesity.

Objective measurement of habitual sedentary behaviour and physical activity in pre-school children: Comparison of activPAL with Actigraph monitors

Sedentary behaviour is associated with increased energy intake and obesity in young children. The Actigraph is well established for measurement of both free-living sedentary behaviour and physical activity. Estimates of sedentary behaviour and physical activity by the novel activPAL have not yet been published in children but the validity for measurement of both constructs in young children is established. The present study aimed at comparing measures of sedentary behaviour and physical activity between the two monitors in a convenience sample of free-living pre-school children. Twenty-three pre-school children (mean age: 4.5 years) wore the activPAL and the Actigraph accelerometer simultaneously during waking hours for a mean of 5.6 d and 10 h/d. Measures of daily mean percentage time sedentary (lying/sitting and standing with no translocation) and physically active were compared between the two monitors at a group and individual level. Daily mean percentage of time sedentary was 74.6 (SD 6.8) for the Actigraph and 78.9 (SD 4.3) for the activPAL. Daily mean percentage of time physically active (light intensity plus MVPA) was 25.4 (SD 6.8) for the Actigraph and 21.1 (SD 4.3) for the activPAL. Rank order correlations between the two devices were statistically significant (r = 0.676, P<0.001). Differences in percentage of time spent sedentary and physically active between the monitors were significant (paired t-test, P<0.001). The Bland–Altman analysis (Fig. 1) showed that for estimates of percentage of the day spent sedentary there was a difference of 4.3% (SD 4.8) of daily time (limits of agreement 14.0 to 5.4%) for the Actigraph relative to the activPAL.

Carers' perspectives on a weight loss intervention for obese adults with intellectual disabilities: a qualitative study

The prevalence of obesity rates has been reported to be higher in adults with Intellectual Disabilities (ID) than in the general population (1) . It is likely that multi-component weight management interventions that involve carers could have considerable impact on process and potentially on actual weight loss for adults with ID (2) . To date no studies have explored the role of carers in supporting adults with ID and obesity during a weight loss programme. The aims of the present study were (i) to explore perceptions of carers supporting adults with ID as they participated in a 6-month multi-component weight loss intervention (TAKE 5), (ii) to identify strategies that carers and participants adopt to overcome barriers to changes in lifestyle, and (iii) to record carers’ perceptions of the acceptability and utility of the multicomponent weight loss intervention. TAKE 5 is a multi-component weight loss intervention that is consistent with recommendations included in current clinical guidelines (3) . TAKE 5 comprised nine individual sessions delivered to fifty-four adults (‡ 18 years) with ID and obesity (BMI ‡ 30 kg/m 2 ), involving carers (paid carers or family carers) to support the participants where appropriate. The TAKE 5 intervention aimed for a 5 % weight loss from initial body weight after 6 months. A purposive sampling method was used to incorporate the experiences of twenty-four carers who were paid (n 16) or family carers (n 8) and who supported participants who successfully achieved a 5 % weight loss (n 12) or did not (n 12). One to one semi-structured interviews were conducted and later transcribed verbatim at week 24. The transcripts were analysed using ATLAS ti 5.2 software, alongside a ‘thematic analysis’ (4) as a qualitative analytical method. The main themes that emerged on analysis were carers’ perceptions on participants’ health; barriers and facilitators in weight loss and carers’ perceptions of the multi-component weight loss intervention. Carers described the weight loss as being beneficial to participants’ health. Furthermore, they discussed their efforts to encourage and aid participants to improve their diet and physical activity. However, lack of sufficient support and poor communication among carer colleagues were identified as being inhibitory. The need for resources tailored to aid weight loss among adults with ID was also highlighted. This study identified specific facilitators and barriers experienced by carers during the process of supporting obese adults with ID to lose weight. Future research should utilise these findings to develop appropriate and effective weight management interventions for this group.