Accelerometer-measured daily physical activity related to aerobic fitness in children and adolescents

Abstract

Maximum oxygen uptake ([Vdot]O_2PEAK) is generally considered to be the best single marker for aerobic fitness. While a positive relationship between daily physical activity and aerobic fitness has been established in adults, the relationship appears less clear in children and adolescents. The purpose of this paper is to summarise recently published data on the relationship between daily physical activity, as measured by accelerometers, and [Vdot]O_2PEAK in children and adolescents. A PubMed search was performed on 29 October 2010 to identify relevant articles. Studies were considered relevant if they included measurement of daily physical activity by accelerometry and related to a [Vdot]O_2PEAK either measured directly at a maximal exercise test or estimated from maximal power output. A total of nine studies were identified, with a total number of 6116 children and adolescents investigated. Most studies reported a low-to-moderate relationship (r = 0.10–0.45) between objectively measured daily physical activity and [Vdot]O_2PEAK. No conclusive evidence exists that physical activity of higher intensities are more closely related to [Vdot]O_2PEAK, than lower intensities.     

The Measurement of Postures

Abstract

Thirty-three college men doing the toe-touch test were used as subjects to ascertain the relative contribution of the back and hamstring muscles to hip joint flexibility. The subjects, performing six tests over a 5-week period, were photographed during each of their tests. Anthropometric measurements were taken prior to testing to determine if there was any relationship to flexibility. Making use of concentric circles and marking reference points on the subject prior to testing, it was possible to ascertain the curvature of the back, the angle of straight back flexibility, and the angle of bent back flexibility.

Results indicate that the extensibility of the hamstring muscles appeared to be one of the main contributing factors to hip joint flexion, and since the warm-up did not affect the flexibility of the back, one might conclude that the back made no increased contribution to hip joint flexion, as measured in this study. There was no significant relationship to the angle of bent back flexibility.     

Gender Role and Sport Competition Anxiety: A Re-examination

Abstract

The present study tested whether there were significant sport competition anxiety differences among sex-typed, androgynous, and cross sex-typed subjects and whether these differences were consistent with gender schema theory (Bem, 1981b).

Approximately 700 subjects were administered the Bem Sex-Role Inventory (BSRI) and, using two methods of scoring, 216 subjects were selected because of being either sex-typed (masculine males, feminine females), cross sex-typed (masculine females, feminine males) or androgynous (males and females who have strong masculine and feminine dimensions). Each subject was tested for competition anxiety using the Sport Competition Anxiety Test (SCAT). A one-way ANOVA of SCAT scores by group was significant, F(5,210) = 6.52, p < .001. Post-hoc analysis revealed that feminine females had significantly more competitive trait anxiety than all other groups and androgynous females were more anxious than masculine males (p < .05). The results are discussed in terms of gender schema theory.     

Developmental Change in Notetaking during Scientific Inquiry

This paper addresses the development in children’s and adults’ awareness of the benefits of writing through the analysis of change in notetaking while engaged in scientific inquiry over 10 weeks. Participants were given a notebook that they could choose to use. Our results indicate consistent differences between the performance of adults versus children and also across time. First, there were clear differences in the number of participants who chose to take notes. Second, not only did adults write more notes than children, but also the adults’ mean number of notes slightly increased over time, whereas children’s notes actually decreased in frequency. Third, children and adults differed in the types of notes they took. These results are interpreted in terms of participants’ awareness of what needs to be noted in a scientific task and why it needs to be noted, and they suggest implications for educational practice. First, because learners often have inaccurate representations of the task demands and their own future state of knowledge, they do not perceive the utility of notetaking. Second, because of these misperceptions, learners do not refer back to their notes and thereby miss feedback that would spur the refinement of their metacognitive (particularly metastrategic) knowledge and strategy use. Educators need to design opportunities for students to engage in activities that increase metacognitive knowledge of their own cognitive abilities and the demands of the task.     

Elementary Students' Laboratory Record Keeping During Scientific Inquiry

The present study examines the mutual interaction between students' writing and scientific reasoning among sixth‐grade students (age 11–12 years) engaged in scientific inquiry. The experimental task was designed to promote spontaneous record keeping compared to previous task designs by increasing the saliency of task requirements, with the design goal of making the relationship between record keeping and inquiry strategies more explicit and visible. Compared to previous studies, this new task design resulted both in a higher amount of record keeping overall and in a higher quality of information, which is interpreted to be a result of increased participants’ metatask and metastrategic knowledge arising from greater engagement with the task. The study found a significant relationship between the quality of students' record keeping and the inquiry strategies that were investigated. However, this relationship varied depending on the type of inquiry strategy. Strategies that are employed during the design of experiments (i.e., factorial combination strategy and control‐of‐variables strategy [CVS]) were statistically related to the number of complete comments (plans and intents), but not with the total number of comments. In contrast, the study found that for strategies employed while evaluating evidence (i.e., drawing inferences), student production of quality records is a necessary but not sufficient condition for effective evidence evaluation; in addition to recording high‐quality information, students must also review their records (both from design and evaluation phases).     

Influence of different attentional focus on EMG amplitude and contraction duration during the bench press at different speeds

The purpose of this study was to investigate whether using different focus affects electromyographic (EMG) amplitude and contraction duration during bench press performed at explosive and controlled speeds. Eighteen young male individuals were familiarized with the procedure and performed the one-maximum repetition (1RM) test in the first session. In the second session, participants performed the bench press exercise at 50% of the 1RM with 3 different attentional focuses (regular focus on moving the load vs contracting the pectoralis vs contracting the triceps) at 2 speed conditions (controlled vs maximal speed). During the controlled speed condition, focusing on using either the pectoralis or the triceps muscles increased pectoralis normalized EMG (nEMG) by 6% (95% CI 3–8%; p = 0.0001) and 4% nEMG (95% CI 1–7%; p = 0.0096), respectively, compared with the regular focus condition. Triceps activity was increased by 4% nEMG (95% CI 0–7%; p = 0.0308) at the controlled speed condition during the triceps focus. During the explosive speed condition, the use of different focuses had no effect. The different attentional focus resulted in comparable contraction duration for the measured muscles when the exercise was performed explosively. Using internal focus to increase EMG amplitude seems to function only during conditions of controlled speed.     

A systematic review of propulsion from the flutter kick – What can we learn from the dolphin kick?

Propulsion, one of the most important factors in front crawl swimming performance, is generated from both the upper and lower limbs, yet little is known about the mechanisms of propulsion from the alternating movements of the lower limbs in the flutter kick (FK). The purpose of this systematic review was to review the literature relating to the mechanisms of propulsion from FK in front crawl. There was limited information about the mechanisms of propulsion in FK. Since movements of the lower limbs are similar between FK and the dolphin kick (DK), mechanisms of propulsion from DK were reviewed to better understand propulsion from FK. Recent evidence suggests that propulsion in DK is generated in conjunction with formation and shedding of vortices. Similar vortex structures have been observed in FK. Visualisation and simulation techniques, such as particle image velocimetry (PIV) and computational fluid dynamics (CFD), are non-invasive tools that can effectively model water flow without impacting swimming technique. These technologies allow researchers to estimate the acceleration of water and, consequently, the propulsive reaction forces acting on the swimmer. Future research should use these technologies to investigate propulsion from FK.     

Reflection as a core student learning activity in higher education - Insights from nearly two decades of academic development

ABSTRACT

Experiential learning (EL) has great potential to prepare students to work on interdisciplinary and global challenges across traditional boundaries, as well as support them in the development of reflective skills. In this study, we explore reflection as a central element for EL in the university wide interdisciplinary course Experts in Teamwork (EiT). Based upon 17 years of experience with the development of EiT, perspectives from the literature, and critically analyzing current practices, we describe two key findings from this ongoing exploration: the need to develop a framework for such a course and the need for training of teaching staff.