The influence of 2 weeks of low-volume high-intensity interval training on health outcomes in adolescent boys

Abstract

The present study aimed to establish whether 2 weeks of high-intensity interval training would have a beneficial effect on aerobic fitness, fat oxidation, blood pressure and body mass index (BMI) in healthy adolescent boys. Ten adolescent boys (15.1 ± 0.3 years, 1.3 ± 0.2 years post-estimated peak height velocity) completed six sessions of Wingate-style high-intensity interval training over a 2-week period. The first session consisted of four sprints with training progressed to seven sprints in the final session. High-intensity interval training had a beneficial effect on maximal O₂ uptake (mean change, ±90% confidence intervals: 0.19 L · min^?1, ±0.19, respectively), on the O₂ uptake at the gas exchange threshold (0.09 L · min^?1, ±0.13) and on the O₂ cost of sub-maximal exercise (–0.04 L · min^?1, ±0.04). A beneficial effect on the contribution of lipid (0.06 g · min^?1, ±0.06) and carbohydrate (–0.23 g · min^?1, ±0.14) oxidation was observed during sub-maximal exercise, but not for the maximal rate of fat oxidation (0.04 g · min^?1, ±0.08). Systolic blood pressure (1 mmHg, ±4) and BMI (0.1 kg · m², ±0.1) were not altered following training. These data demonstrate that meaningful changes in health outcomes are possible in healthy adolescent boys after just six sessions of high-intensity interval training over a 2-week period.     

Variability in muscle damage after eccentric exercise and the repeated bout effect

The first purpose of this study was to determine a possible explanation for the variability in the response to eccentric exercise by having participants repeat the same exercise 1 year apart. The second purpose was to examine whether initial injury in response to eccentric exercise was associated with the extent of the repeated bout effect (RBE). Male students performed 30 eccentric contractions (ECC) of the elbow flexors using a dumbbell set at 80% of the pre-exercise maximal isometric force (MIF). Participants were then classified into low (LR; n=6), medium (MR; n=6), high (HR; n=5), and higher (HrR; n=7) based on the increase in blood creatine kinase (CK) activity. A year later, participants repeated this exercise (ECC30). Four days after ECC30, participants performed 70 eccentric contractions (ECC70). Range of motion, MFI upper arm circumference, soreness, and blood CK activity were measured before and up to 9 days after each bout. The change in the criterion measures following ECC and ECC30 were similar for each group. There were no further changes in all parameters after ECC70 for MR, HR, and HrR, although there was a small increase in CK after ECC70 for LR. LR showed a smaller RBE after ECC70 compared with the other groups. It is concluded that participants who exercised 1 year apart showed remarkably similar responses between the bouts. The extent of the RBE following the second bout for the LR group is less for participants who demonstrate the least evidence of muscle damage after a first exercise bout.     

Characterizing the Achievement Motivation Orientation of Children From Low- and Middle-Income Families

Research Findings: The current study examined achievement motivation orientation in preschool-age children from low- and middle-income families. Participants were 126 children who were attending an urban Head Start site or a private preschool. Children's motivation orientation was assessed as being performance oriented or mastery oriented using a challenging puzzle task (Smiley &; Dweck, 1994 Smiley , P. A. , &; Dweck , C. S. ( 1994 ). Individual differences in achievement goals among young children . Child Development , 65 , 1723 – 1743 .[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Children's verbalizations during the task were coded into performance concern, disengaged, and negative self-evaluation categories. Logistic regression and Mann-Whitney U analyses were conducted to examine differences between income groups in motivation orientation and verbalizations. Patterns of motivation orientation in preschool-age children from low- and middle-income families did not differ after controlling for differences in age and puzzle-solving ability. However, children from low-income families made a significantly higher proportion of performance-related verbalizations while working on the task. Practice or Policy: The findings support the examination of children's private speech as a way to assess cognitive processes underlying achievement motivation. In addition to providing a novel way to identify differences in achievement motivation that may be useful for teachers and researchers, the findings suggest the potential utility of designing interventions that promote positive private speech as a way of supporting mastery-oriented motivation in young children.     

List of Contributors

Biography

List of Contributors     

Evoking and provoking Bourdieu in educational research

This paper provides an introduction to this special issue of the Cambridge Journal of Education on ‘Evoking and provoking Bourdieu in educational research’. In the course of providing a critical synopsis of each paper, we consider how and why the authors work with and after Bourdieu, both evoking and provoking his thinking tools (particularly field, capital and habitus, but also doxa, misrecognition and illusio) and his methodological disposition that rejects ‘epistemological innocence’. We note that Bourdieu himself invited such provocation and that this is especially needed as the social continues to change, given the new spatialities of globalisation and growing social and economic inequalities. That is, we acknowledge that the empirical and the theoretical are always imbricated in each other, a theme pursued throughout the collection.