Validation of two accelerometers to determine mechanical loading of physical activities in children     

Ursina Meyer  Dominique Ernst  Silvia Schott  Claudia Riera  Jan Hattendorf  Jacqueline Romkes 《Journal of sports sciences》2015,33(16):1702-1709

The purpose of this study was to assess the validity of accelerometers using force plates (i.e., ground reaction force (GRF)) during the performance of different tasks of daily physical activity in children. Thirteen children (10.1 (range 5.4–15.7) years, 3 girls) wore two accelerometers (ActiGraph GT3X+ (ACT), GENEA (GEN)) at the hip that provide raw acceleration signals at 100 Hz. Participants completed different tasks (walking, jogging, running, landings from boxes of different height, rope skipping, dancing) on a force plate. GRF was collected for one step per trial (10 trials) for ambulatory movements and for all landings (10 trials), rope skips and dance procedures. Accelerometer outputs as peak loading (g) per activity were averaged. ANOVA, correlation analyses and Bland–Altman plots were computed to determine validity of accelerometers using GRF. There was a main effect of task with increasing acceleration values in tasks with increasing locomotion speed and landing height (P < 0.001). Data from ACT and GEN correlated with GRF (r = 0.90 and 0.89, respectively) and between each other (r = 0.98), but both accelerometers consistently overestimated GRF. The new generation of accelerometer models that allow raw signal detection are reasonably accurate to measure impact loading of bone in children, although they systematically overestimate GRF.  相似文献   

Advanced Math Course Taking: Effects on Math Achievement and College Enrollment     

Soo-yong Byun  Matthew J. Irvin  Bethany A. Bell 《Journal of Experimental Education》2015,83(4):439-468

Using data from the Educational Longitudinal Study of 2002–2006, the authors investigated the effects of advanced math course taking on math achievement and college enrollment and how such effects varied by socioeconomic status and race/ethnicity. Results from propensity score matching and sensitivity analyses showed that advanced math course taking had positive effects on math achievement and college enrollment. Results also demonstrated that the effect of advanced math course taking on math achievement was greater for low socioeconomic status students than for high socioeconomic status students, but smaller for Black students than for White students. No interaction effects were found for college enrollment. Limitations, policy implications, and future research directions are discussed.  相似文献   

Genetic and Environmental Etiologies of the Longitudinal Relations Between Prereading Skills and Reading          下载免费PDF全文

Micaela E. Christopher  Jacqueline Hulslander  Brian Byrne  Stefan Samuelsson  Janice M. Keenan  Bruce Pennington  John C. DeFries  Sally J. Wadsworth  Erik Willcutt  Richard K. Olson 《Child development》2015,86(2):342-361

The present study explored the environmental and genetic etiologies of the longitudinal relations between prereading skills and reading and spelling. Twin pairs (n = 489) were assessed before kindergarten (M = 4.9 years), post‐first grade (M = 7.4 years), and post‐fourth grade (M = 10.4 years). Genetic influences on five prereading skills (print knowledge, rapid naming, phonological awareness, vocabulary, and verbal memory) were primarily responsible for relations with word reading and spelling. However, relations with post‐fourth‐grade reading comprehension were due to both genetic and shared environmental influences. Genetic and shared environmental influences that were common among the prereading variables covaried with reading and spelling, as did genetic influences unique to verbal memory (only post‐fourth‐grade comprehension), print knowledge, and rapid naming.  相似文献   

Antiracism defined as equitable sociocultural interactions in prekindergarten: Classroom racial composition makes a difference     

Stephanie M. Curenton  Shana E. Rochester  Jacqueline Sims  Nneka Ibekwe-Okafor  Iheoma U. Iruka  Arlene G. García-Miranda  Jessica Whittaker 《Child development》2022,93(3):681-698

This study used secondary data from the My Teaching Partner-Math/Science 2013–2016 randomized control trial to explore whether equitable sociocultural classroom interactions (see Curenton et al., 2019) were associated with the skills of 105 four- and five-year-olds (52% boys; drawn from 20 unique video recordings of preschool teachers/classrooms; 43% were Black, Latine, Asian, or other racially marginalized learners). Equitable interactions predicted children's skills with effect sizes ranging from small (0.01–0.44) to large (1.00). Moderation analyses revealed that when classrooms had more racially marginalized learners, teachers’ use of equitable disciplinary and personalized learning practices were associated with higher executive functioning gains across prekindergarten. Findings illustrate how classroom composition can be a key indicator between equitable classroom interactions and young children's early skills.  相似文献   

Employment and further study outcomes for care-experienced graduates in the UK     

Harrison  Neil  Baker  Zoë  Stevenson  Jacqueline 《Higher Education》2022,83(2):357-378

Higher Education - Life outcomes for people who spent time in the care of the state as children (‘care-experienced’) are known to be significantly lower, on average, than for the...  相似文献   

Effect of chainring ovality on joint power during cycling at different workloads and cadences     

Gerda Strutzenberger  Tobias Wunsch  Josef Kroell  Jacqueline Dastl  Hermann Schwameder 《Sports biomechanics / International Society of Biomechanics in Sports》2014,13(2):97-108

Non-circular chainrings theoretically enhance cycling performance by increasing effective chainring diameter and varying crank velocity, but research has failed to consistently reproduce the benefits in cycling trials. The aim of this study was (1) to investigate the effect of different chainring shapes on sagittal knee joint moment and sagittal lower limb joint powers and (2) to investigate whether alterations are affected by cadence and workload. Fourteen elite cyclists cycled in six conditions (70, 90 and 110 rpm, each at 180 and 300 W), for 2 min each, using three chainrings of different ovalities (1.0–1.215). Kinematic data and pedal forces were collected. For most conditions, only the chainring with the highest ovality (1.215) was characterised by smaller sagittal knee joint moments, smaller relative sagittal knee joint power contribution and larger relative sagittal hip joint power contribution, which suggests a change from maximising efficiency to maximising power production. Effect sizes increased with higher cadences, but not with higher workload. This study has application for athletes, clinicians and sports equipment industry as a non-circular chainring can change joint-specific power generation and decrease knee joint moment, but certain ovality seems to be necessary to provoke this effect.  相似文献   

Scientific arguments as learning artifacts: designing for learning from the web with KIE     

Philip Bell  Marcia C. Linn 《International Journal of Science Education》2013,35(8):797-817

We designed Knowledge Integration Environment (KIE) debate projects to take advantage of internet resources and promote student understanding of science. Design decisions were guided by the Scaffolded Knowledge Integration instructional framework. We report on design studies that test and elaborate on our instructional framework. Our learning studies assess the arguments students construct using the Knowledge Integration Environment debate project about light propagation and, explore the relationship between students' views of the nature of science and argument construction. We examine how students use evidence, determine when they add further ideas and claims and measure progress in understanding light propagation. To a modeate degree, students' views of the nature of science align with the quality of the arguments.  相似文献   

SKIPing with teachers: an early years motor skill intervention     

Ali Brian  Jacqueline D. Goodway  Jessica A. Logan  Sue Sutherland 《Physical Education & Sport Pedagogy》2017,22(3):270-282

  相似文献   

How can clusters sustain performance? The role of network strength, network openness, and environmental uncertainty   总被引：2，自引：0，他引：2  

Andreas B. Eisingerich  Simon J. Bell  Paul Tracey 《Research Policy》2010,39(2):239-253

This paper draws on social network theory to develop a model of regional cluster performance. We suggest that high performing regional clusters are underpinned by (1) network strength and (2) network openness, but that the effects of these on the performance of a cluster as a whole are moderated by environmental uncertainty. Specifically, the positive effects of network openness on cluster performance tend to increase as environmental uncertainty increases, while the positive effects of network strength on cluster performance tend to decrease as environmental uncertainty increases. Our findings have theoretical and practical implications for social network research in general, and cluster research in particular.  相似文献   

Scotland's Universities     

R. E. Bell 《比较教育学》2000,36(2):163-175

  相似文献