Physical Activity and Sedentary Time Patterns in Children and Adolescents with Cystic Fibrosis and Age- and Sex-Matched Healthy Controls

Background:Regular physical activity (PA) is increasingly recognised as important in the care of patients with Cystic Fibrosis (CF) but there is a dearth of evidence regarding physical activity levels (PAL) or how these are accrued in those with CF.Methods:Physical activity was measured by a hip-worn accelerometer for seven consecutive days by eighteen children (10 boys; 12.4 ± 2.8 years) with mild to moderate CF and eighteen age- and sex-matched controls (10 boys; 12.5 ± 2.7 years).Results:Both CF and healthy children demonstrated similar PAL and patterns of accumulation across the intensity spectrum, with higher levels of PA during weekdays in both groups. FEV1 was predicted by high-light PA in CF compared to low-light PA in healthy children.Conclusion:These findings highlight weekends and light PA as areas warranting further research for the development of effective intervention strategies to increase PA in the youth CF population

Investigating the Relative Exercise Intensity of Exergames in Prepubertal Children

Objective:Literature remains equivocal as to whether exergames elicit energy expenditure (EE) commensurate with physical activity guidelines. Such discrepancies may be attributable to a reliance on absolute exercise intensities which fail to account for differences in cardiorespiratory fitness levels. Materials and Methods:Thirty four pre-pubertal children (20 boys, 10.8±1.0 yrs) completed a 30 minute exergame (two 15 minute games; Kinect Adventures!; Xbox 360) and an incremental treadmill test to determine peak O2 throughout which breath-by-breath gas exchange was measured. Results:Both games elicited moderate intensity (5.7±1.5 and 5.5±1.4 METs), with 36% demonstrating a mean EE in excess of 6.0 METs, commensurate with vigorous intensity. Furthermore, boys demonstrated higher EE during both games (Game 1: boys, 6.0±1.7 vs. girls, 5.2±1.0; Game 2: boys, 6.0±1.4 vs. girls, 4.9±1.2 METs; P<0.05). Hierarchical linear regression revealed sex, maturity and fitness to be significant predictors of EE, accounting for 24%: relative exergame O2=24.53+(2.12*Sex)–(0.42*Maturity offset)–(0.16*relative peak O2). There was no correlation between absolute O2 during the exergames and peak O2 but O2 expressed as a percentage of peak O2 was correlated with peak O2 during both game 1 (r=-0.62, P<0.01) and game 2 (r =-0.59, P<0.01).Conclusion:The present findings provide further evidence that exergames can elicit energy expenditures commensurate with national physical activity guidelines and extend our understanding of the mediators of EE. Specifically, cardiorespiratory fitness and sex must both be considered in the design and implementation of future interventions seeking to utilise exergames to enhance physical activity levels and/or cardiorespiratory fitness

Promotion of physical activity for adolescents with cystic fibrosis: A qualitative study of UK multi-disciplinary cystic fibrosis teams

BackgroundThe Cystic Fibrosis Trust recently published a standards of care document which stated that patients should be given a physical activity (PA) programme based on their motivations, fitness, and willingness to be active. However, there remains much debate regarding the roles and responsibilities for PA promotion, as well as “optimal” recommendations and advice. This study aimed to qualitatively explore cystic fibrosis (CF) multidisciplinary teams (MDTs) advice, recommendations and practices relating to PA promotion for adolescents with CF.MethodSemi-structured interviews were conducted with fifteen members of CF MDTs (11 physiotherapists, two dieticians and two paediatricians). Thematic analysis was used to analyse the data.ResultsMajor themes identified were: 1) structure of MDTs, 2) recommendations relating to intensities, durations and types of PA, and 3) use of exercise testing. Participants reported variation between MDTs in terms of who is responsible for promoting and supporting PA, the nature of advice given to patients, and the use of exercise testing. Participants consistently lacked confidence in their own or others’ knowledge to provide standardised recommendations to patients and highlighted that PA promotion and support was often overlooked during busy periods.ConclusionsDespite its importance, PA support and promotion is not always prioritised. MDTs lack confidence in their ability to promote PA. Standardised advice and training relating to optimal intensities, durations and types of PA would provide a baseline from which to individualise advice to each patient and could increase confidence in PA promotion among MDTs

Validity and reliability of the HomeSPACE-II instrument to assess the influence of the home physical environment on children’s physical activity and sedentary behaviour

The home physical environment has an important influence on children’s physical activity levels and time spent in sedentary behaviours. The aim of this study was to validate the HomeSPACE-II instrument for use in two-storey homes, to measure physical environmental factors that influence children’s physical activity and sedentary behaviours within the home. Parents (n = 31) with at least one child aged 9–13 years completed the instrument independently alongside a criterion-trained researcher, then one week later alone, to assess validity and reliability, respectively. Parents were mostly female (87.1%) and university educated (61.3%) with a mean age of 41.68 ± 4 years, while houses were mostly semi-detached or terraced (61.3%) with two parents (87.1%). Intra-class correlation coefficients, Pearson correlation coefficients and Kappa statistics revealed that most items, outside of accessibility and size measures, had strong reliability and validity (94% having ICC > 0.60 and 97% having r > 0.80). Excluding physical activity equipment, accessibility items with lower reliability and validity had low between-subject variation. The HomeSPACE-II instrument covers a wide range of parameters within the home and demonstrated strong validity and reliability, suggesting it is a useful tool for measuring physical factors that influence children’s physical activity and sedentary behaviour within the home

Cross-Validation and Comparison of Energy Expenditure Prediction Models Using Count-Based and Raw Accelerometer Data in Youth

Background: Machine learning may improve energy expenditure (EE) prediction from body-worn accelerometers. However, machine learning models are rarely cross-validated in an independent sample, and the use of machine learning raises additional questions including the effect of accelerometer placement and data type (count vs. raw) for optimal EE prediction. Purpose: To assess the accuracy of artificial neural network (ANN) models for EE prediction in youth using count-based or raw data from accelerometers worn on the hip, wrist, or in combination, and compare these to count-based, EE regression equations. Methods: Data were collected in two settings; one (n = 27) to calibrate the EE prediction models, and the other (n = 34) for model cross-validation. Participants wore a portable metabolic analyzer (EE criterion) and accelerometers on the left wrist and right hip while completing 30 minutes of exergames (calibration, cross-validation) and a maximal exercise test (calibration only). Six ANNs were created from the calibration data, separately by accelerometer placement (hip, wrist, combination) and data format (count-based, raw) to predict EE (15-second epochs). Three count-based linear regression equations were also developed for comparison to the ANNs. Results: The count-based, hip ANN demonstrated lower error (RMSE: 1.2 METs) than all other ANNs (RMSE: 1.7–3.6 METs) and EE regression equations (RMSE: 1.5–3.2 METs). However, all models showed bias toward the mean. Conclusion: An ANN developed for hip-worn accelerometers had higher accuracy for EE prediction during an exergame session than wrist or combination ANNs, and ANNs developed using count-based data had higher accuracy than ANNs developed using raw data

Investigating the Modulatory Role of Chronological and Biological Age on Performance Predictors in Youth Swimmers

The aim of this study was to determine the modulatory roles of biological maturity and age on the predictors of performance in youth swimmers and their stability over a six-month training cycle