CURRICULUM SEQUENCING AND THE ACQUISITION OF CLOCK-READING SKILLS AMONG CHINESE AND FLEMISH CHILDREN

The present study addresses the impact of the curriculum on primary school children’s acquisition of clock-reading knowledge from analog and digital clocks. Focusing on Chinese and Flemish children’s clock-reading knowledge, the study is about whether the differences in sequencing of learning and instruction opportunities—as defined by the curriculum—result in differences in accuracy and development of clock-reading knowledge. By means of (1) an in-depth qualitative analysis of the Chinese and Flemish mathematics curriculum standards and textbooks and (2) a quantitative analysis of 11,743 students’ accuracy in reading the time, the current study mirrors the differential impact of alternative curriculum designs for primary education. The results of the analyses reveal that Chinese children acquire clock-reading knowledge—for analog and digital clocks—2 years earlier than their Flemish peers, due to a 2-year earlier exposure. Discussing these results, it is argued that the Flemish curriculum tends to underestimate what children are capable of and that clock-reading within the Flemish primary mathematics curriculum builds on dated assumptions and research results. Building on these outcomes, it is argued that curriculum development should be the result of collaborative inquiry involving policy makers, researchers, and teachers.     

Physical and Physiological Characteristics of Elite Volleyball Players

Abstract

The purpose of this study was to characterize the body fat, maximum aerobic power and maximum anaerobic power of elite junior wrestlers. The study was conducted in conjunction with an elite wrestler training camp. Wrestlers (n = 39) from ages 14 to 18 qualified for the camp and volunteered as subjects. Measurements were made for body composition (skinfold thickness), maximal aerobic power (treadmill run), and maximal anaerobic power of the arms and legs (Wingate test). Body fat averaged (±SD) 7.2% (±2.4), whereas the means (±SD) for maximal aerobic power, arm power, and leg power were 51.2(±9.3) ml/kg min^-1, 390.7 (±92) watts, and 549.1 ± 101 watts, respectively. Elite junior wrestlers appear to have a similar percentage of body fat, lower maximum aerobic power and higher relative anaerobic power compared to elite collegiate and senior wrestlers.     

Squat Jump Performance During Growth in Both Sexes

The purpose of this cross-sectional study was to investigate leg muscle power and compare two activities (jumping and cycling) in 383 girls and 407 boys ages 9–19 years. Results in anthropometric characteristics and jumping performance were comparable until midadolescence, and sex differences were observed. Lean leg volume (LLV) was the reason for most of the variance (76% in girls and 88% in boys) in jumping performance. However, the LLV exponent was higher than expected in boys but not girls. Therefore, unidentified qualitative changes of muscle function during growth in boys must be considered. The squat jump index (SJI) was highly correlated to cycling peak power (CPP; N = 790, r = .94, p < .001). Although prediction error of CPP from SJI was less than 5% when considering each sex-and-age group, individual errors mounted to 40%. Due to its practicability, SJI is recommended in large-scale developmental prospective studies. However, cycling and jumping protocols are not interchangeable when measuring peak power values.     

Central Circulatory Adaptations to Physical Training

Abstract

The bradycardia effect of a 10-week jogging program was studied in 13 previously sedentary middle-aged subjects (seven women and six men). This response during standardized submaximal treadmill walking and leg cycling was related to changes in cardiac output ([Qdot]), stroke volume (SV), and arteriovenous oxygen differences (a-vO₂ diff). Heart rate (HR) response was also studied during load carrying and arm cycling tasks, and a [Vdot]O₂ max test was administered. All tests were repeated posttraining. The posttraining increases in [Vdot]O₂ max (ml/kg × min^-1) were 19.7% and 14.8% for the men and women respectively. Training also produced significant reductions in submaximal HR and Q during treadmill and leg cycling exercise. A-vO₂ diff rose, while there were no changes in [Vdot]O₂ during the submaximal work tasks, suggesting either altered blood flow or a greater capacity to utilize O₂ by the working muscle. Both men and women showed significant reductions in HR during the arm cycling and load carrying as well. These data suggest that a jogging program can alter cardiovascular function in tasks other than running. The magnitude and direction of change showed no sex differences; therefore, it was also concluded that there are no differences in the trainability of previously sedentary middle-aged men and women.