This study examined whether or not activity monitor data collected as part of a typical 7-day physical activity (PA) measurement protocol can be expected to be missing at random. A total of 315 participants (9–18 years) each wore a SenseWear Armband monitor for 7 consecutive days. Participants were classified as “compliant” (86 boys and 124 girls) if they had recorded accelerometer data during 70% or more of the predefined awake time (7 AM–10 PM) on four different days; and “non-compliant” (44 boys and 51 girls) when not meeting these criteria. Linear mixed models were used to examine differences in energy expenditure (EE) levels by compliance across 10 different time periods. The results indicated that non-compliant girls were older (13.4 ± 2.9 vs. 12.2 ± 2.5) and taller (156.8 ± 10.3 vs. 152.8 ± 11.3) than their same gender compliant peers (P < .05). Comparisons of EE rates at segmented portions of the day revealed no differences between compliant and non-compliant groups (P ≥ .05). Differences in EE ranged from ?0.32 kcal · kg?1 · h?1 (before school time) to 0.62 kcal · kg?1 · h?1 (physical education class) in boys and ?0.39 kcal · kg?1 · h?1 (transportation from school) to 0.37 kcal · kg?1 · hour?1 (recess) in girls. The results showed that compliant and non-compliant individuals differed in a few demographic characteristics but exhibited similar activity patterns. This suggests that data were considered to be missing at random, but additional work is needed to confirm this observation in a representative sample of children using other types of activity monitors and protocols. 相似文献
In several of his papers, Charles S. Peirce illustrates processes of interpreting and understanding signs by examples from second language vocabulary teaching and learning. The insights conveyed by means of these little pedagogical scenarios are not meant as contributions to the psychology of second language learning, but they aim at elucidating fundamental semiotic implications of knowledge acquisition in general. Peirce's semiotic premise that a well‐understood sign is one that represents an object and creates an interpretant is essential to the understanding of how new words and signs in general can be taught and learned. The article argues that Peirce's theory of the object of the sign, especially of the necessity of collateral experience of the object of a sign, can help to understand the riddle posed by of the Meno paradox of the impossibility of learning what we do not yet know. It examines the semiotic implications of the didactic methods of teaching and learning through translation, ostension, mental and real images, as well as metacognition, and it shows how icons, indices, and symbols are essential to learning new words. 相似文献
‘A tribute to Dr J. Rogge’ aims to systematically review muscle activity and muscle fatigue during sustained submaximal quasi-isometric knee extension exercise (hiking) related to Olympic dinghy sailing as a tribute to Dr Rogge’s merits in the world of sports. Dr Jacques Rogge is not only the former President of the International Olympic Committee, he was also an orthopaedic surgeon and a keen sailor, competing at three Olympic Games. In 1972, in fulfilment of the requirements for the degree of Master in Sports Medicine, he was the first who studied a sailors’ muscle activity by means of invasive needle electromyography (EMG) during a specific sailing technique (hiking) on a self-constructed sailing ergometer. Hiking is a bilateral and multi-joint submaximal quasi-isometric movement which dinghy sailors use to optimize boat speed and to prevent the boat from capsizing. Large stresses are generated in the anterior muscles that cross the knee and hip joint, mainly employing the quadriceps at an intensity of 30–40% maximal voluntary contraction (MVC), sometimes exceeding 100% MVC. Better sailing level is partially determined by a lower rate of neuromuscular fatigue during hiking and for ≈60% predicted by a higher maximal isometric quadriceps strength. Although useful in exercise testing, prediction of hiking endurance capacity based on the changes in surface EMG in thigh and trunk muscles during a hiking maintenance task is not reliable. This could probably be explained by the varying exercise intensity and joint angles, and the great number of muscles and joints involved in hiking.Highlights
Dr Jacques Rogge, former president of the International Olympic Committee and Olympic Finn sailor, was the first to study muscle activity during sailing using invasive needle EMG to obtain his Master degree in Sports Medicine at the Ghent University.
Hiking is a critical bilateral and multi-joint movement during dinghy racing, accounting for >60% of the total upwind leg time. Hiking generates large stresses in the anterior muscles that cross the knee and hip joint.
Hiking is considered as a quasi-isometric bilateral knee extension exercise. Muscle activity measurements during sailing, recorded by means of EMG, show a mean contraction intensity of 30-40% maximal voluntary contraction with peaks exceeding 100%.
Hiking performance is strongly related to the development of neuromuscular fatigue in the quadriceps muscle. Since maximal strength is an important determinant of neuromuscular fatigue during hiking, combined strength and endurance training should be incorporated in the training program of dinghy sailors.
Brain injury research in sport employs a variety of physical models equipped with accelerometers. These acceleration signals are commonly processed using filters. The purpose of this research was to determine the effect of applying filters with different cutoff frequencies to the acceleration signals used as input for finite element modeling of the brain. Signals were generated from reconstructions of concussion events from American football and ice hockey in the laboratory using a Hybrid III headform. The resulting acceleration signals were used as input for the University College Dublin Brain Trauma Model after being processed with filters. The results indicated that using a filter with a cutoff of 300 Hz or higher had little effect on the resulting strain measures. In some cases there was some effect of the filters on the peak linear (8–30g) and rotational measures (1000–4000 rad/s2), but little effect on the finite element strain result (approximately 2–6 %). The short duration and high magnitude accelerations, such as the puck impact, were most affected by the cutoff frequency of different filters. 相似文献
This study sought to assess current and future school psychologists’ attitudes toward and preparedness to address the needs of lesbian, gay, bisexual, and transgender (LGBT) students in schools. Two‐hundred seventy‐nine school psychologists (n = 162, 58%) and school psychology graduate students (n = 117, 42%) were included in the study. Participants completed measures of attitudes toward LGBT students, preparedness to address the needs of LGBT youth, and social desirability. For both school psychologists and graduate students, increased education was associated with improved attitudes and increased preparedness to treat LGBT youth. For school psychologists, presence of a gay‐straight alliance was associated with increased knowledge about LGBT youth, as well as higher ratings of preparedness to treat LGBT youth; the same associations did not hold true for the graduate students. These findings have implications for the training and practice of school psychologists in addressing the needs of LGBT youth in schools. 相似文献
Increased activity of multiple stakeholders (e.g. agents and owners) have created new challenges for some coaches working in professional sports clubs. The purpose of this project was to draw attention to the normative or accepted practices inherent in sport work, some of the day-to-day realities of some coaches working in this context, and to understand how coaches’ perceptions of other stakeholders come to bear on their individual circumstances, career expectations/objectives and professional agency. Data were generated from semi-structured interviews with seven professional basketball coaches who worked in top-level European clubs. The analysis reveals the coach’s relationships between some owners and agents differed with respect to exercising professional agency, and, coach’s decisions and actions were tied to their professional ideals as well as understandings of what they need to undertake their work effectively and negotiation and/or adjustment strategies. Occasionally coach’s work practices could be viewed as antithetical to employment security, however, the presence of insecurity was at times embraced and used strategically to affect workers’ career decisions. Amid contemporary regional geo-political shifts, this work aids examinations of global sport settings, structures and issues that may contour sporting professionals’ lives. 相似文献
This study aimed to explore how children with learning disabilities (LD) perceive their quality of life (QoL) and to compare self‐reports and proxy reports regarding their QoL. Children with LD, their typically developing peers, their parents and teachers responded to the child, parent, and teacher forms of KINDLR Questionnaire for Measuring Health‐Related Quality of Life (Ravens‐Sieberer & Bullinger, 1998). Findings showed that children with LD reported significantly lower QoL scores than those reported by typically developing peers. Intraclass correlation coefficients (ICCs) and t‐test results showed that agreement between child reports and parent‐proxy reports was either low or moderate on each QoL dimension. Findings of the study may be used to raise awareness regarding the social and educational needs of children with LD in Turkey. 相似文献