新高考背景下的高中物理建模教学设计

新时期高考聚焦关键能力考查,注重科学探究与思维建模能力的培养,要求学生理解并合理使用物理模型解决问题。文章基于高中人教版教材,以“速度变化快慢的描述—加速度”一节为例,打破传统授课顺序,利用加涅信息加工理论进行物理建模教学设计,探究如何将物理建模教育显化,引导学生通过建模学会提取关键信息并加工,全面深化对物理学的认知,提高思维能力和探究意识,助力中学物理建模教学。     

Statistical modelling of knee valgus during a continuous jump test

Landing with the knee in a valgus position is recognized as a risk factor for anterior cruciate ligament (ACL) injury. Using linear and non-linear regression analyses, the purpose of this study was to examine the correlation between two-dimensional (2D) knee valgus and three-dimensional (3D) knee kinematics measured during a jump landing task. Twenty-eight female collegiate athletes participated. All participants were required to perform a continuous jump test. The average maximum angles of abduction and internal tibial rotation during landing were measured using the Point Cluster Technique. Average peak knee valgus angle was measured using a 2D approach. Linear and non-linear regression analyses between 2D valgus and 3D knee abduction, and between 2D valgus and 3D internal tibial rotation, were performed. The R2 value between 2D valgus and 3D knee abduction was significantly different from zero and had a moderate correlation for all models, whereas the R2 value between 2D valgus and 3D internal tibial rotation was not significantly different from zero. The 2D approach could be used to screen a specific group of individuals for risk of ACL injury; however, using frontal plane 2D analysis of valgus motion to evaluate internal tibial rotation is not advised.     

Physique and performance for track and field events

Evidence of the importance of physique in the athletics disciplines is supported by the persistence of certain characteristics over long periods, despite marked secular changes in the source population. These characteristics may also result in physiological benefits such as effective thermoregulation or a greater power-to-weight ratio. Coaches and athletes are often convinced of weight or fat loss benefits based on personal or anecdotal experience, intuition, and "trained eye" observation of successful competitors. This may entice athletes into adopting unbalanced, erratic or highly restrictive eating patterns that increase the risk for nutrient deficiencies, and disordered eating. Despite heavy training loads and often extreme diets, some athletes fall short of their physique goals as ultimately phenotype is under genetic control. Professionals assisting athletes with physique management need to be highly skilled in anthropometry and require a thorough understanding of sports-specific nutrition requirements. Careful assessment of the risks and benefits of various approaches to weight and fat loss is required before they are recommended to athletes.     

Nutritional strategies to optimize training and racing in middle-distance athletes

Middle-distance athletes implement a dynamic continuum in training volume, duration, and intensity that utilizes all energy-producing pathways and muscle fibre types. At the centre of this periodized training regimen should be a periodized nutritional approach that takes into account acute and seasonal nutritional needs induced by specific training and competition loads. The majority of a middle-distance athlete's training and racing is dependant upon carbohydrate-derived energy provision. Thus, to support this training and racing intensity, a high carbohydrate intake should be targeted. The required energy expenditure throughout each training phase varies significantly, and thus the total energy intake should also vary accordingly to better maintain an ideal body composition. Optimizing acute recovery is highly dependant upon the immediate consumption of carbohydrate to maximize glycogen resynthesis rates. To optimize longer-term recovery, protein in conjunction with carbohydrate should be consumed. Supplementation of beta-alanine or sodium bicarbonate has been shown to augment intra- and extracellular buffering capacities, which may lead to a small performance increase. Future studies should aim to alter specific exercise (resistance vs. endurance) and/or nutrition stimuli and measure downstream effects at multiple levels that include gene and molecular signalling pathways, leading to muscle protein synthesis, that result in optimized phenotypic adaptation and performance.     

The use of physiological, anthropometric, and skill data to predict selection in a talent-identified junior volleyball squad

The aim of this study was to determine whether physiological, anthropometric, and skill test results could discriminate between junior volleyball players of varying ability. Twenty-eight junior volleyball players competed for selection in a talent-identification volleyball programme. Participants underwent measurements of stature, standing reach stature, body mass, skinfold thickness, overhead medicine ball throw, vertical jump, spike jump, 5-m and 10-m speed, "T" test agility, maximal aerobic power, and passing, setting, serving, and spiking technique and accuracy. A discriminant analysis was conducted on the selected and non-selected groups to obtain a regression equation that could be used to predict selection in junior volleyball squads based on the dependent variables. Passing and serving technique were the only significant variables included in the discriminant analysis. Cross-validation results showed that 17 of 19 selected players (89.5%) and 5 of 9 non-selected players (55.6%) were correctly classified into selected and non-selected groups, respectively, providing an overall predictive accuracy of 78.6%. The results of this study demonstrate that selected skill test results (i.e. subjective coach evaluations of passing technique and serving technique), but not physiological and anthropometric data, discriminate between successful and unsuccessful talent-identified junior volleyball players. These results demonstrate the importance of developing passing and serving technique in talent-identified junior volleyball players.     

The role of upper torso and pelvis rotation in driving performance during the golf swing

While the role of the upper torso and pelvis in driving performance is anecdotally appreciated by golf instructors, their actual biomechanical role is unclear. The aims of this study were to describe upper torso and pelvis rotation and velocity during the golf swing and determine their role in ball velocity. One hundred recreational golfers underwent a biomechanical golf swing analysis using their own driver. Upper torso and pelvic rotation and velocity, and torso-pelvic separation and velocity, were measured for each swing. Ball velocity was assessed with a golf launch monitor. Group differences (groups based on ball velocity) and moderate relationships (r > or = 0.50; P < 0.001) were observed between an increase in ball velocity and the following variables: increased torso-pelvic separation at the top of the swing, maximum torso-pelvic separation, maximum upper torso rotation velocity, upper torso rotational velocity at lead arm parallel and last 40 ms before impact, maximum torso-pelvic separation velocity and torso-pelvic separation velocity at both lead arm parallel and at the last 40 ms before impact. Torso-pelvic separation contributes to greater upper torso rotation velocity and torso-pelvic separation velocity during the downswing, ultimately contributing to greater ball velocity. Golf instructors can consider increasing ball velocity by maximizing separation between the upper torso and pelvis at the top of and initiation of the downswing.     

Open feedback in gymnastic judging causes conformity bias based on informational influencing

The aims of this study were twofold: (1) to determine whether open feedback (i.e. the ability to hear or see the scores of colleague judges after each performance) would lead judges in gymnastics to conform with their colleagues, and (2) to identify the underlying process on which this conformity is based. Twenty-three certified Flemish judges in women's gymnastics were randomly divided into panels of a maximum of five judges. These panels had to rate the same 30 videotaped individual vaults: 15 in phase 1 and 15 in phase 2. Two independent variables were orthogonally manipulated: feedback (or no feedback) during phase 1 and feedback (or no feedback) during phase 2. The results of phase 1 revealed that the variation between the judges' scores was less within panels that had received feedback than within panels that had not received feedback. We therefore conclude that the availability of feedback elicits conformity among gymnastic judges. The results of phase 2 indicated that this conformity continued even when feedback was no longer provided, suggesting that the observed conformity was based on informational influencing (i.e. because of uncertainty about the correct responses) and not on normative influencing (i.e. out of fear of standing out in the group).     

Children's experiences of fun and enjoyment during a season of sport education

This paper reports on a 16-week sport education (SE) unit with just over 70 year 5 students (M age = 10.04 years) in one United Kingdom school during the spring and summer terms and discusses students' SE experiences. Student interviews were conducted throughout the season and a questionnaire on different motivation aspects was administered prior to and before completing the SE season. We report and examine the data in relation to hypothesized influences on fun and enjoyment, including being part of a team, autonomy, and improving game play. The principal reasons SE may be more enjoyable than previous physical education lessons include the greater opportunities for autonomy, affiliation, and competition, plus perceived learning.     

The CSGU: a measure of controllability, stability, globality, and universality attributions

This article reports initial evidence of construct validity for a four-factor measure of attributions assessing the dimensions of controllability, stability, globality, and universality (the CSGU). In Study 1, using confirmatory factor analysis, factors were confirmed across least successful and most successful conditions. In Study 2, following less successful performances, correlations supported hypothesized relationships between subscales of the CSGU and subscales of the CDSII (McAuley, Duncan, & Russell, 1992). In Study 3, following less successful performances, moderated hierarchical regression analyses demonstrated that individuals have higher subsequent self-efficacy when they perceive causes of performance as controllable, and/or specific, and/or universal. An interaction for controllability and stability demonstrated that if causes are perceived as likely to recur, it is important to perceive that causes are controllable. Researchers are encouraged to use the CSGU to examine main and interactive effects of controllability and generalizability attributions upon outcomes such as self-efficacy, emotions, and performance.