Pedagogical content knowledge: an integrative component within the knowledge base for teaching.     

Jan H. Van Driel  William R. Veal  Fred J. J. M. Janssen 《Teaching and Teacher Education》2001,17(8)

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Physical and Physiological Characteristics of Elite Volleyball Players     

Jacqueline Puhl  Samuel Case  Steven Fleck  Peter Van Handel 《Research quarterly for exercise and sport》2013,84(3):257-262

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.  相似文献   

Squat Jump Performance During Growth in Both Sexes     

Eric Doré  Mario Bedu  Emmanuel Van Praagh 《Research quarterly for exercise and sport》2013,84(4):517-524

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.  相似文献   

Physical activity and older adults: a review of health benefits and the effectiveness of interventions     

AH Taylor  NT Cable  G Faulkner  M Hillsdon  M Narici  AK Van Der Bij 《Journal of sports sciences》2013,31(8):703-725

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Central Circulatory Adaptations to Physical Training     

Peter J. Van Handel  David L. Costill  Leroy H. Getchell 《Research quarterly for exercise and sport》2013,84(4):815-823

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.  相似文献   

A Study of Certain Factors in Their Relation to the Play of Children     

D. B. Van Dalen 《Research quarterly for exercise and sport》2013,84(4):279-290

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The effect of video‐feedback on the learning of the tennis service by intermediate players     

P.C.W. Van Wieringen  H.H. Emmen  R.J. Bootsma  M. Hoogesteger  H.T.A. Whiting 《Journal of sports sciences》2013,31(2):153-162

Effects of video‐feedback on improvement of the tennis service were investigated in subjects having at least 2 years of playing experience in tennis. The experiment was carried out in an indoor tennis hall under normal training conditions.

Subjects were randomly divided into three groups: a video‐feedback training (VFT) group, a traditional training (TT) group and a control group, each consisting of 22 subjects. While the subjects of the control group received no training at all, subjects in both the VFT and TT groups were trained twice weekly during 5 consecutive weeks. Each training session lasted 40 min, of which 30 min was spent on actual practice in training of the service. The remaining 10 min was spent on watching, analysing and discussing video recordings of either their own service performed during the training session (VFT group), or ground strokes and volleys of top level players (TT group). Both the VFT and TT group showed significantly greater improvements in both achievement scores and form (technique) scores than did the control group. No differences, however, could be demonstrated between the VFT and TT group, indicating that the subjects of the former group did not benefit from the video‐feedback they received.

While form scores correlated significantly (P < 0.001) with the velocity of the served ball, no such relation between form scores and spatial accuracy was apparent.  相似文献   

Anthropometric characteristics of elite female junior rowers     

Jan Bourgois  Albrecht L. Claessens  Melissa Janssens  Bart Van Renterghem  Ruth Loos  Martine Thomis 《Journal of sports sciences》2013,31(3):195-202

During the 1997 Federation Internationale des Societes d'Aviron (FISA) World Junior Rowing Championships, the anthropometric characteristics of 245 female junior rowers aged 17.5 ± 0.8 years (mean ± s) were assessed. Twenty-seven body dimensions (body mass, 6 heights or lengths, 4 breadths, 10 girths and 6 skinfolds) were measured in total. The elite female junior rowers were taller (174.5 ± 6.2 cm) and heavier (69.5 ± 6.2 kg), with greater length, breadth and girth dimensions, but lower skinfold thicknesses than a representative sample of Flemish (Belgian) girls of the same chronological age. An anthropometric profile chart was constructed that was rowing-specific and norms were established. Compared with scullers, sweep rowers were heavier (+4.2 kg) and taller (+2.8 cm), with greater length, breadth (except for femur width) and girth dimensions (except for calf girth). Sweep rowers also had greater skinfold thicknesses (except for the thigh and calf skinfolds). Finalists were heavier (+3.6 kg) and taller (+3.9 cm), with greater length, breadth (except for femur width) and girth dimensions (except for calf girth) than non-finalists. No significant differences were found for skinfold thicknesses between finalists and non-finalists.  相似文献   

Training UiA library staff in the use of computer databases     

John van Loo  Frank Van der Auweka  Julien Van Borm 《Health information and libraries journal》1995,12(1):65-67

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Influence of ski materials on muscle activity     

J P Clarys  L Van Puymbroeck  J Publie  E Bollens  J Cabri  B De Witte 《Journal of sports sciences》1986,4(2):129-139

The purpose of this study was to examine whether differences in construction between the compact ski, the racing ski and the soft ski influence the behavioural and electromuscular responses of the user. Eight qualified male ski instructors performed two 'shuss' trials and three different basic turns. Six muscles (M. biceps femoris, M. gastrocnemius lateralis and medialis, M. rectus femoris, M. vastus lateralis and M. tibialis anterior) were studied, using a conventional but portable electromyographic (EMG) registration with telemetric synchronization, active electrodes and a six-channel portable data recorder. Muscle contractions were continuously registered and visualized in raw EMG form and linear envelopes. The differences between the mean rectified EMG data of dynamic contractions while skiing and the mean rectified EMG data of the maximal voluntary contraction were used in the primary analysis of data, from which the participation levels of the muscles investigated could be calculated for each type of ski. Based on this comparison, differences between the effects on muscle activity of the three types of skis were unimportant. In a second phase, the normalized linear envelopes of all subjects were graphically superimposed and averaged. This was performed for each muscle, for each movement, for each leg and for each ski tested. The EMG data were considered in combination with anthropometric values, with snow characteristics and with the velocity of skiing. This study showed systematic differences between the use of the racing, soft and compact ski. On average the soft ski showed the lowest muscle activity patterns and thus the most economical muscular efforts for all muscles investigated and within all movements.  相似文献