Reliability and validity of field-based measures of leg stiffness and reactive strength index in youths

Abstract

The aim of the study was to assess the reliability of a mobile contact mat in measuring a range of stretch–shortening cycle parameters in young adolescents. Additionally, vertical leg stiffness using contact mat data was validated against a criterion method using force–time data. The reliability study involved 18 youths completing a habituation and three separate test sessions, while 20 youths completed a single test session for the validity study. Participants completed three trials of a squat jump, countermovement jump, and maximal hopping test and a single trial of repeated sub-maximal hopping at 2.0 Hz and 2.5 Hz. All tests were performed on the contact mat. Reliability statistics included repeated-measures analysis of variance, intraclass correlation coefficient, and coefficient of variation (CV), while the correlation coefficient (r) and typical error of estimate (TEE) were reported for the validity study. Squat jump height was the most reliable measure (CV = 8.64%), while leg stiffness during sub-maximal hopping, and reactive strength index produced moderate reliability (CV = 10.17–13.93% and 13.98% respectively). Measures of leg stiffness obtained from contact mat data during sub-maximal hopping were in agreement with the criterion measure (r = 0.92–0.95; TEE = 6.5–7.5%), but not during maximal hopping (r = 0.59; TEE = 41.9%). The contact mat was deemed a valid tool for measuring stretch–shortening cycle ability in sub-maximal but not maximal hopping. Although reliability of performance was generally moderate, the tests offer a replicable assessment method for use with paediatric populations.     

Effects of playing surface on physiological responses and performance variables in a controlled football simulation

Abstract

In spite of the increased acceptance of artificial turf in football, few studies have investigated if matches are altered by the type of surface used and no research has compared physiological responses to football activity on artificial and natural surfaces. In the present study, participants performed a football match simulation on high-quality artificial and natural surfaces. Neither mean heart rate (171 ± 9 beats · min^?1 vs. 171 ± 9 beats · min^?1; P > 0.05) nor blood lactate (4.8 ± 1.6 mM vs. 5.3 ± 1.8 mM; P > 0.05) differed between the artificial and natural surface, respectively. Measures of sprint, jumping and agility performance declined through the match simulation but surface type did not affect the decrease in performance. For example, the fatigue index of repeated sprints did not differ (P > 0.05) between the artificial, (6.9 ± 2.1%) and natural surface (7.4 ± 2.4%). The ability to turn after sprinting was affected by surface type but this difference was dependent on the type of turn. Although there were small differences in the ability to perform certain movements between artificial and natural surfaces, the results suggest that fatigue and physiological responses to football activity do not differ markedly between surface-type using the high-quality pitches of the present study.     

Pathways from parental stimulation of children’s curiosity to high school science course accomplishments and science career interest and skill

Curiosity is fundamental to scientific inquiry and pursuance. Parents are important in encouraging children’s involvement in science. This longitudinal study examined pathways from parental stimulation of children’s curiosity per se to their science acquisition (SA). A latent variable of SA was indicated by the inter-related variables of high school science course accomplishments, career interest, and skill. A conceptual model investigated parental stimulation of children’s curiosity as related to SA via science intrinsic motivation and science achievement. The Fullerton Longitudinal Study provided data spanning school entry through high school (N?=?118). Parental stimulation of curiosity at age 8 years comprised exposing children to new experiences, promoting curiosity, encouraging asking questions, and taking children to a museum. Intrinsic motivation was measured at ages 9, 10, and 13 years, and achievement at ages 9, 10, and 11 years. Structural equation modelling was used for analyses. Controlling for socio-economic status, parental stimulation of curiosity bore positive and significant relations to science intrinsic motivation and achievement, which in turn related to SA. Gender neither related to stimulation of curiosity nor contributed to the model. Findings highlight the importance of parental stimulation of children’s curiosity in facilitating trajectories into science, and relevance to science education is discussed.     

Becoming a Supervisor: Doctoral Student Perceptions of the Training Experience

Thirteen doctoral students, 7 Caucasians and 6 Hispanics, participated over 3 semesters of practicum/internship in a qualitative research project exploring the experience of becoming supervisors. A follow‐up study with 5 different doctoral students confirmed and refined findings 1½ years later. The research team of 2 female faculty members and 1 male research assistant (the authors) identified 6 themes emerging from individual and group interviews with supervisors‐in‐training regarding the process of becoming a supervisor: (a) learning, (b) supervisee growth, (c) individual uniqueness, (d) reflection, (e) connections, and (f) putting it all together.     

Graphonomics,automaticity and handwriting assessment

A recent review of handwriting research in Literacy concluded that current curricula of handwriting education focus too much on writing style and neatness and neglect the aspect of handwriting automaticity. This conclusion is supported by evidence in the field of graphonomic research, where a range of experiments have been used to investigate this issue from a movement perspective. The present article offers a brief introduction to a graphonomic approach to handwriting analysis and the findings of graphonomic research about handwriting automaticity. These findings indicate that attentional control to any characteristic of the writing process (e.g. direction, lexical status, movement, style) results in an impairment of handwriting automaticity. These findings support and add a new dimension to previous conclusions.     

LONG-TERM OUTCOMES OF EARLY CHILDHOOD SCIENCE EDUCATION: INSIGHTS FROM A CROSS-NATIONAL COMPARATIVE CASE STUDY ON CONCEPTUAL UNDERSTANDING OF SCIENCE

The purpose of this research was to explore the long-term outcomes of either participating or not participating in early childhood science education on grade 6 students?? conceptual understanding of science. The research is situated in a conceptual framework that evokes Piagetian developmental levels as both potential curriculum constraints and potential models of efficacy. The research design was a multiple case study of grade 6 children from 3 schools in China (n?=?140) who started formal science education in the third grade and grade 6 children from 3 matched schools in Australia (n?=?105) who started learning science in kindergarten. The students?? understanding was assessed by a science quiz and an in-depth interview. The data showed that participating children from the high socioeconomic schools in China and Australia had similar understandings of science. Divergence between the medium and low socioeconomic schools, however, indicated that the grounding in early childhood science education in Australia may have placed these children at an advantage. Alternative explanations for the divergence, including the nature of classroom instruction in the two countries, are discussed.     

Book reviews

Interactive Television. TV of the future or the Future of TV Eds. Jens F. Jensen & Cathy Toscan, Media & Cultural Studies 1, Aalborg University Press, Aalborg, Denmark, 1999, ISBN 87–7307–625–2 / ISSN 1399–1752 http://www.forlag.auc.dk/en/

Killer Content: Strategies for Web Content and E‐Commerce written by Mai‐Ian Tomsen. Addison‐Wesley, 2000, 224 pages, ISBN: 0201657864. http://www.aw.com

The Business of Digital Television written by Chris Forrester. Focal Press, Oxford, Auckland, Boston, Johannesburg, Melbourne, New Delphi, 2000. ISBN 0 240 51606 0. http://www.focalpress.com     

Exploring the Effects of Television Viewing on Perceived Life Quality: A Combined Perspective of Material Value and Upward Social Comparison

American television programs have been criticized for being filled with images endorsing capitalist consumerism and for being weighted toward the upper middle classes. This study proposed that heavy viewing of these distorted representations may culminate in decreases in viewers' life satisfaction. A path model investigated this supposition, based on material value and social comparison perspectives. Surveys were administered to 225 adults in a northeastern town in the United States, and the data were subjected to path analysis. The findings of this study suggest that heavy television viewing may be associated with material value, estimates of other people's affluence, and perceived gaps between the self and others in material affluence. Of importance, the findings also suggest that the perceived gaps between the self and others may be associated both with dissatisfaction with personal life and dissatisfaction with current social equality, whereas material value may be associated only with dissatisfaction with personal life.