TIMSS in a Western European Context

This special issue focuses on national findings and analyses from five Western European countries that participated in the Third International Mathematics and Science Study (TIMSS). TIMSS is an international, com-parative study designed to provide policy makers, educators, researchers, and practitioners with information about mathematics and science achieve-ment and its learning contexts in order to enhance mathematics and science learning within and across systems of education. TIMSS is conducted under the auspices of the International Association for the Eval-uation of Educational Achievement (IEA). It is co-ordinated by the Inter-national Study Centre at Boston College in the United States. More than 40 educational systems participate in TIMSS. It is the most complex IEA study to date and the largest international comparative study on education-al achievement ever undertaken. The study focuses on three populations o

Estimating Youth Locomotion Ground Reaction Forces Using an Accelerometer-Based Activity Monitor

To address a variety of questions pertaining to the interactions between physical activity, musculoskeletal loading and musculoskeletal health/injury/adaptation, simple methods are needed to quantify, outside a laboratory setting, the forces acting on the human body during daily activities. The purpose of this study was to develop a statistically based model to estimate peak vertical ground reaction force (pVGRF) during youth gait. 20 girls (10.9±0.9 years) and 15 boys (12.5±0.6 years) wore a Biotrainer AM over their right hip. Six walking and six running trials were completed after a standard warm-up. Average AM intensity (g) and pVGRF (N) during stance were determined. Repeated measures mixed effects regression models to estimate pVGRF from Biotrainer activity monitor acceleration in youth (girls 10–12, boys 12–14 years) while walking and running were developed. Log transformed pVGRF had a statistically significant relationship with activity monitor acceleration, centered mass, sex (girl), type of locomotion (run), and locomotion type-acceleration interaction controlling for subject as a random effect. A generalized regression model without subject specific random effects was also developed. The average absolute differences between the actual and predicted pVGRF were 5.2% (1.6% standard deviation) and 9% (4.2% standard deviation) using the mixed and generalized models, respectively. The results of this study support the use of estimating pVGRF from hip acceleration using a mixed model regression equation