Reliability of laser Doppler,near-infrared spectroscopy and Doppler ultrasound for peripheral blood flow measurements during and after exercise in the heat

This study examined the test-retest reliability of near-infrared spectroscopy (NIRS), laser Doppler flowmetry (LDF) and Doppler ultrasound to assess exercise-induced haemodynamics. Nine men completed two identical trials consisting of 25-min submaximal cycling at first ventilatory threshold followed by repeated 30-s bouts of high-intensity (90% of peak power) cycling in 32.8 ± 0.4°C and 32 ± 5% relative humidity (RH). NIRS (tissue oxygenation index [TOI] and total haemoglobin [tHb]) and LDF (perfusion units [PU]) signals were monitored continuously during exercise, and leg blood flow was assessed by Doppler ultrasound at baseline and after exercise. Cutaneous vascular conductance (CVC; PU/mean arterial pressure (MAP)) was expressed as the percentage change from baseline (%CVC_BL). Coefficients of variation (CVs) as indicators of absolute reliability were 18.7–28.4%, 20.2–33.1%, 42.5–59.8%, 7.8–12.4% and 22.2–30.3% for PU, CVC, %CVC_BL, TOI and tHb, respectively. CVs for these variables improved as exercise continued beyond 10 min. CVs for baseline and post-exercise leg blood flow were 17.8% and 10.5%, respectively. CVs for PU, tHb (r² = 0.062) and TOI (r² = 0.002) were not correlated (P > 0.05). Most variables demonstrated CVs lower than the expected changes (35%) induced by training or heat stress; however, minimum of 10 min exercise is recommended for more reliable measurements.     

Changes in organisation of instep kicking as a function of wearing compression and textured materials

This study investigated effects of wearing compression garments and textured insoles on modes of movement organisation emerging during performance of lower limb interceptive actions in association football. Participants were six skilled (age?=?15.67?±?0.74 years) and six less-skilled (age?=?15.17?±?1.1 years) football players. All participants performed 20 instep kicks with maximum velocity in four randomly organised insoles and socks conditions, (a) Smooth Socks with Smooth Insoles (SSSI); (b) Smooth Socks with Textured Insoles (SSTI); (c) Compression Socks with Smooth Insoles (CSSI); and (d), Compression Socks with Textured Insoles (CSTI). Results showed that, when wearing textured and compression materials (CSSI condition), less-skilled participants displayed significantly greater hip extension and flexion towards the ball contact phase, indicating larger ranges of motion in the kicking limb than in other conditions. Less-skilled participants also demonstrated greater variability in knee–ankle intralimb (angle–angle plots) coordination modes in the CSTI condition. Findings suggested that use of textured and compression materials increased attunement to somatosensory information from lower limb movement, to regulate performance of dynamic interceptive actions like kicking, especially in less-skilled individuals.     

Asymptotic Stability of a Class of Non-linear Singularly Perturbed Systems2

Sufficient conditions are obtained to guarantee the asymptotic stability of a class of non-linear singularly perturbed systems. A procedure for constructing a Lyapunov function for such a class of systems is given, and a clearly defined domain of attraction of the equilibrium is obtained. A stabilizing feedback control for such systems is also proposed.     

Universals and specifics in learning strategies: Explaining adolescent mathematics, science, and reading achievement across 34 countries

We examined whether strategies of memorization, transfer through elaboration, and metacognition accounted for reading, science, and mathematics achievement across 34 countries. 158,848 fifteen-year-olds completed a reading literacy test and a questionnaire. Of these students, 88,401 completed a science test, and 88,590 completed a mathematics test. We analyzed the data using multi-level regressions of Rasch-estimated test scores and modeled differences across countries and across schools. Students who reported using memorization strategies often scored lower in all subjects. Transfer through elaboration was not significantly linked to any achievement scores. Lastly, students reporting greater use of metacognitive strategies often scored higher. Compared to students in individualistic societies, to achievement scores of students in collective cultures were linked more strongly to schoolmates' use of metacognitive strategies and less strongly to their own use of metacognitive strategies. These results highlight how cultural contexts can moderate the links between adolescents' learning strategies and their academic achievement.     

Why the Constraints-Led Approach is not Teaching Games for Understanding: a clarification

Background: There is some apparent confusion regarding similarities and differences between two popular physical education (PE) pedagogical frameworks, that is, the Constraints-Led Approach (CLA) and Teaching Games for Understanding (TGfU).

Purpose: Our aim in this commentary is to detail important theoretical and pedagogical concepts that distinguish these approaches, as well as to recognise where commonalities exist.

Findings: In particular, we note that TGfU had its roots in the 1960s in the absence of a substantial theoretical framework, although several attempts to retrospectively scaffold theories around TGfU have subsequently emerged in the literature. TGfU is a learner-centred approach to PE in which teachers are encouraged to design modified games to develop the learner's understanding of tactical concepts. In contrast, the CLA has arisen more recently from the umbrella of Nonlinear Pedagogy (NLP), emerging from the empirically rich theoretical framework of ecological dynamics. The CLA adopts a ‘learner–environment’ scale of analysis in which practitioners are encouraged to identify and modify interacting constraints (of task, environment and learner) to facilitate the coupling of each learner's perceptual and action systems during learning. The CLA is a broader framework which has been adapted for the design of (re)learning environments in PE, sport and movement therapy. Other key distinctions between the approaches include: the overall goals; the way in which the learner and the learning process are modelled; the use of questioning as a pedagogical tool; the focus on individual differences vs. generic concepts; and how progressions and skill interjections are planned and implemented.

Conclusions: Despite such distinctions, the two approaches are somewhat harmonious and key similarities include: their holistic perspective of the learner; the proposed role of the teacher and the design characteristics of learning tasks in each. Both TGfU and the CLA have a powerful central focus on the nature of learning activities undertaken by each individual learner. This clarification of TGFU and the CLA is intended to act as a catalyst for more empirical work into the complementarity of these juxtaposed pedagogical approaches to learning design.     

Learning about the types of plastic wastes: effectiveness of inquiry learning strategies

This study aims to examine the impacts of the inquiry learning strategies employed in a ‘Plastic Education Project’ on primary students' knowledge, beliefs and intended behaviour in Hong Kong. Student questionnaires and a test on plastic types were adopted for data collection. Results reveal that the inquiry learning strategies significantly improved students' knowledge of the types of plastic wastes and their corresponding beliefs. However, the strategies seemed not to change students' intended behaviour regarding plastic waste classification and management. The implications of the study for further learning and teaching in environmental education are discussed.