Optimal sampling frequency in recording of resistance training exercises

The purpose of this study was to analyse the raw lifting speed collected during four different resistance training exercises to assess the optimal sampling frequency. Eight physically active participants performed sets of Squat Jumps, Countermovement Jumps, Squats and Bench Presses at a maximal lifting speed. A linear encoder was used to measure the instantaneous speed at a 200 Hz sampling rate. Subsequently, the power spectrum of the signal was computed by evaluating its Discrete Fourier Transform. The sampling frequency needed to reconstruct the signals with an error of less than 0.1% was f_99.9 = 11.615 ± 2.680 Hz for the exercise exhibiting the largest bandwidth, with the absolute highest individual value being 17.467 Hz. There was no difference between sets in any of the exercises. Using the closest integer sampling frequency value (25 Hz) yielded a reconstruction of the signal up to 99.975 ± 0.025% of its total in the worst case. In conclusion, a sampling rate of 25 Hz or above is more than adequate to record raw speed data and compute power during resistance training exercises, even under the most extreme circumstances during explosive exercises. Higher sampling frequencies provide no increase in the recording precision and may instead have adverse effects on the overall data quality.     

How does education have an impact on ethnocentrism? A structural equation analysis of cognitive,occupational status and network mechanisms

Previous studies have distinguished cognitive, occupational status and network mechanisms in the relation between education and ethnocentrism. Hypotheses on these mediating mechanisms are derived from socialization theory, realistic group threat and contact theory. In the current study we use structural equation modeling to investigate the explanatory power of these three mechanisms simultaneously. The analysis is based on a representative population survey from the Netherlands (NELLS 2009, n = 1910). The results show that more than half of the initial association between education and ethnocentrism can be attributed to cognitive ability and occupational status mechanisms. The remaining part of the overall association, however, still has to be modeled as a direct relationship between education and ethnocentrism. This direct association can be attributed either to social desirability or to a direct liberalizing effect of education on social and political attitudes. Our analysis tentatively suggests that the rise of average education levels in Western societies might lead to less ethnocentric attitudes via the cognitive sophistication mechanism.     

What motivates enrolment in programming MOOCs?

Learners who enrol in massive open online courses (MOOCs) have different backgrounds and tend to have different motivations than learners in traditional courses. Based on value-expectancy theory, an instrument was developed to measure motivation for enrolling in a programming MOOC. A study with 1229 adult participants in Estonian-language programming course “About Programming” was conducted to validate the instrument. Results of confirmatory factor analysis validated the 7-factor scale named factors influencing enrolment in MOOC (FIEM). FIEM comprises three factors of expectancies, three factors of values and one factor of social influence. The highest and lowest rated motivational factors influencing enrolment in programming MOOC are discussed in the paper. Interest in and expectations for the course, personal suitability of distance learning and suitability for family and work are the highest-rated motivational factors for those who enrol in MOOC. Usefulness related to own children, social influence and usefulness to related to certification were the lowest rated. The results of this study can be useful for designers of programming MOOCs and the developed scale might be used in future studies.     

Trajectories of Adjustment in a Brazilian Sample of Street-Involved Youth

Trajectories of adjustment were examined in a sample of street-involved youth across a 1-year period. Participants (N = 113; M_age = 14.18 years; 80.5% male, 91% non-White) were recruited in three Brazilian cities. Interviews conducted at three time points included six measures of physical and psychological adjustment. Unconditional growth models revealed linear declines over time (i.e., improved adjustment) on three indicators: health symptoms, sexual risk behaviors, and negative affect. There were no linear changes in drug use, positive affect, or life satisfaction. Conditional growth models revealed few significant effects for age or gender, but ratings of stressful life events moderated longitudinal changes in health symptoms, drug use, and negative affect. Implications for practice, policy, and theory are discussed.     

Physical Activity Practices in Elementary Schools and Associations With Physical Education Staffing and Training

Purpose: Authorities recommend that schools provide a variety of opportunities for students to obtain physical activity (PA) before, during, and after school. This study assessed the prevalence of several school PA practices—including measures of quantity and quality of physical education (PE)—in elementary schools and examined the associations of PA practices with school resources (PE staffing, training, and facilities). Method: Surveys were obtained from respondents in nationally representative samples of elementary schools from 2009–2010 to 2011–2012 (1,831 schools). Results: Few schools (20.8%) provided students with PE class every day, but most (76.3%) had an appropriate PE student-to-teacher ratio ( ≤ 25:1). Many schools (74.0%) offered 20 min of recess daily, but fewer than half offered organized opportunities for PA before or after school (e.g., sports). After controlling for demographics and school size, having a full-time PE teacher and requiring PE teachers to obtain PE-related continuing education (CE) were associated with PE practices such as offering ≥ 150 min of PE per week (for 3rd-grade students) and testing PE knowledge, skills, and fitness. Required CE was also associated with a higher likelihood of offering PA during the school day (i.e., activity breaks and PA outside of PE class) and before or after the school day (i.e., afterschool PA programs). Conclusion: Few schools offer a broad array of PA programming. However, PE staffing and CE are positively associated with many PA practices including those outside of PE, possibly indicating that PE staff serve a crucial role in promoting a whole-school PA-supportive environment.     

Effect of Practice on True Score and Intra-Individual Variability for Reaction and Movement Times for Simple and Complex Movements

Abstract

The effect of practice on individual differences and intra-individual variability in reaction and movement times were studied for simple and complex, discrete, motor tasks. Changes with practice for intertrial correlations of adjacent trials and the effects of an increasing number of interpolated trials on intertrial correlations were also observed. For both tasks and for both reaction and movement times, the intra-individual variability decreased with practice. The true score variability for reaction time on both tasks and for movement time on the simple task shows little change with practice. On the complex task, true score variability for movement time decreases with practice. For movement time, adjacent trial correlations increase during the early practice trials then remain stable. For reaction time adjacent trial correlations increase throughout practice. Remoteness effects on intertrial correlations were found for both movement and reaction times for both tasks.     

Lifestyles and gendered patterns of leisure and sporting interests among Irish adolescents

This paper strives to provide an insight into the multifaceted relationships that young people have, examining the social, cultural and institutional discourses, which shape their lives. We set out to discuss, from an empirical poststructuralist perspective, the way in which Irish adolescents write about the reality of their lives and privilege certain practices and forms of subjectivity. We are particularly interested in the role and significance of physical activity in the lives of young people, asking what institutional and cultural discourses are brought into play to construct particular identities and social practices associated with leisure and sporting interests. This paper focuses on a purposeful sample of 168 written narratives of Irish post-primary students (14–17 years of age), chosen to represent the gender of students, a range of rural and urban school locales from different geographic locations and single sex and co-educational schools. We focus on the inter-relationships between (1) family and friends; (2) community-localism and tradition; (3) commodification and globalisation; (4) popular culture; and (5) gendered patterns of leisure and sporting interests. The family is a strong focal point for these young people as are their friends and being part of a community. The young people (boys in particular) are significant consumers of ‘media sport’ and both girls and boys were knowledgeable of national and international politics. We also comment on the extent to which female and male adolescents negotiate, similarly or differently, culturally dominant discourses within physical activity and sport, with significantly more boys choosing to write about physical activity and sport in their narratives.     

Exercise training increases the S-Klotho plasma levels in sedentary middle-aged adults: A randomised controlled trial. The FIT-AGEING study

ABSTRACT

This study aimed to investigate the effects of different training modalities on the soluble Klotho (S-Klotho) plasma levels in sedentary middle-aged adults. A total of 74 middle-aged adults (53.4 ± 5.0 years old; 52.7% women) were enrolled in the FIT-AGEING study. We conducted a 12-week randomised controlled trial. The participants were randomly assigned to 4 different groups: (i) a control group (no exercise), (ii) a physical activity recommendation from the World Health Organization group (PAR), (iii) a high intensity interval training group (HIIT), and (iv) a high intensity interval training group adding whole-body electromyostimulation training group (HIIT-EMS). S-Klotho plasma levels, anthropometric measurements, and body composition variables were measured before and after the intervention programme. All exercise training modalities induced an increase in the S-Klotho plasma levels (all P ≤ 0.019) without statistical differences between them (all P ≥ 0.696). We found a positive association between changes in lean mass index and changes in the S-Klotho plasma levels, whereas a negative association was reported between changes in fat mass outcomes and changes in the S-Klotho plasma levels after our intervention study. In conclusion, our results suggest that the link between exercise training and the increase in S-Klotho plasma levels could be mediated by a decrease of fat mass and an increase of lean mass.