Individual calibration of accelerometers in children and their health-related implications

This study compared children’s physical activity (PA) levels, the prevalence of children meeting current guidelines of ≥60 minutes of daily moderate to vigorous PA (MVPA), and PA-health associations using individually calibrated (IC) and empirical accelerometer cutpoints. Data from 75 (n = 32 boys) 10–12 year old children were included in this study. Clustered cardiometabolic (CM) risk, directly measured cardiorespiratory fitness (CRF), anthropometric and 7 day accelerometer data were included within analysis. PA data were classified using Froude anchored IC, Evenson et al. (Evenson, K. R., Catellier, D. J., Gill, K., Ondrak, K. S., &; McMurray, R. G. (2008). Calibration of two objective measures of physical activity for children. Journal of Sports Sciences, 26(14), 1557–1565. doi:10.1080/02640410802334196) (Ev) and Mackintosh et al. (Mackintosh, K. A., Fairclough, S. J., Stratton, G., &; Ridgers, N. D. (2012). A calibration protocol for population-specific accelerometer cutpoints in children. PLoS One, 7(5), e36919. doi:10.1371/journal.pone.0036919) (Mack) cutpoints. The proportion of the cohort meeting ≥60mins MVPA/day ranged from 37%-56% depending on the cutpoints used. Reported PA differed significantly across the cutpoint sets. IC LPA and MPA were predictors of CRF (LPA: standardised β = 0.32, p = 0.002, MPA: standardised β = 0.27 p = 0.013). IC MPA also predicted BMI Z-score (standardised β = ?0.35, p = 0.004). Ev VPA was a predictor of BMI Z-score (standardised β = ?0.33, p = 0.012). Cutpoint choice has a substantial impact on reported PA levels though no significant associations with CM risk were observed. Froude IC cutpoints represent a promising approach towards classifying children’s PA data.     

A test-retest assessment of the effects of mental load on ratings of affect,arousal and perceived exertion during submaximal cycling

This study aimed to test the effects of mental (i.e. executive) load during a dual physical-mental task on ratings of perceived exertion (RPE), affective valence, and arousal. The protocol included two dual tasks with matched physical demands but different executive demands (2-back and oddball), carried out on different days. The procedure was run twice to assess the sensitivity and stability of RPE, valence and arousal across the two trials. Linear mixed-effects analyses showed less positive valence (?0.44 points on average in a 1–9 scale; R_β² = 0.074 [CI90%, 0.052–0.098]), and heightened arousal (+0.13 points on average in a 1–9 scale; R_β² = 0.006 [CI90%, 0.001–0.015]), for the high executive load condition, but showed no effect of mental load on RPE. Separated analyses for the two task trials yielded best-fitting models that were identical across trials for RPE and valence, but not for arousal. Model fitting was improved by assuming a 1-level autoregressive covariance structure for all analyses. In conclusion, executive load during a dual physical-mental task modulates the emotional response to effort, but not RPE. The autoregressive covariance suggests that people tend to anchor estimates on prior ones, which imposes certain limits on scales' usability.     

Modeling educational choices. A binomial logit model applied to the demand for Higher Education

This paper presents a microeconomic analysis of the choice of universitydegree course that individuals make on finishing their Secondary studies(four-year university degree or three-year university degree), andcontains the theoretical framework as well as empirical results. Themodel selected for our analysis is a binomial logit model. This model,which can be seen as a special case of a general model of utilitymaximization, deals with those aspects of the economics of educationalchoice that are regarded as important in the literature of this subject:academic aptitude, the social background in which the students havegrown up, family income, employment prospects, etc. By using survey dataon educational choices of Spanish High School graduates (cross-sectionaldata), we investigate to what extent the theoretical determinants areconfirmed in practice. The results of the estimation by maximumlikelihood of the logit model, and which allow us to analyze theinfluence of the explanatory variables on the probability of choosing afour-year university degree, show how social background, family earningsand scholastic ability explain, mainly, the educational choice ofstudents. The students from higher socioeconomic status as well as thosewith the best High School curricula are more likely to follow auniversity degree of greater duration.     

Epistemological understanding in science learning: the consistency of representations across contexts

This article addresses the extent to which written diagnostic questions can be used to assess science students' representations of the nature of science. The responses of 731 European science students in upper secondary school and undergraduate programmes to two written diagnostic questions are analysed for consistency. The written questions yielded some insights into students' views. There is evidence that the majority of students in this sample draw upon different epistemological representations in different contexts. The paper concludes with a discussion of the use of data from such questions in science education, and the significance of models of students' epistemological knowledge.     

Concurrent validity and reliability of an iPhone app for the measurement of ankle dorsiflexion and inter-limb asymmetries

The purpose of this investigation was to analyze the validity and reliability of an iPhone app (named: Dorsiflex) for the measurement of weight-bearing ankle dorsiflexion. To do this, twelve healthy participants (age=28.6±2.3 years) performed a weight-bearing lunge test with each leg in five separate occasions, while dorsiflexion angle was simultaneously registered using a professional digital inclinometer and the Dorsiflex iPhone app, which was specifically developed for this study. A total of 120 angles measured both with the digital inclinometer and the app were then compared for validity, reliability and accuracy purposes using several statistical tests. There was an almost perfect correlation between the digital inclinometer and the Dorsiflex app for the measurement of ankle dorsiflexion (r=0.989, 95% CI=0.986-0.993, SEE=0.48º), with trivial, non-significant differences between devices (SMD=0.17, p=0.10). When analyzing the reliability of the app for the measurement of five different trials for each participant, similar coefficients of variation (CV) were observed in comparison with those obtained with the digital inclinometer (Dorsiflex app: CV=5.1±2.3 %; Digital inclinometer: CV=4.9±2.5 %). The results of the present study show that weight-bearing ankle dorsiflexion can be easily, accurately, and reliably evaluated using the Dorsiflex iPhone app.     

The effect of consistent and varied follow-through practice schedules on learning a table tennis backhand

In table tennis the follow-through action after a shot is an important part of skill execution. In this experiment, we aimed to extend literature around the contextual interference effect by investigating whether the way the follow-through is organised in practice affects learning of the backhand shot in table tennis. Thirty unskilled participants were allocated to blocked-variable practice, random-variable practice or a control-constant group and aimed backhand shots towards a target following ball projection from a machine. Each group completed these shots in a pre-test, a training phase with follow-through manipulations, a post-test, and a retention test. The random-variable group improved their shot accuracy from pre-test to post-test and from pre-test to retention test (both P < 0.01, d = 1.03), whereas neither the blocked-variable nor the control-constant group displayed any change in shot accuracy. Practising the follow-through in a random-variable fashion enhanced learning of the preceding shot compared with blocked-variable practice or no follow-through instructions. The benefits of learning motor skills under conditions of high contextual interference also apply to how follow-through actions are organised. The findings are valuable to coaches and suggest that instructions related to the follow-through action should be considered as well as the primary skill itself.