Perception of kinematic characteristics of tennis strokes for anticipating stroke type and direction     

Shim J  Les Carlton G  Kwon YH 《Research quarterly for exercise and sport》2006,77(3):326-339

The purpose of this study was to determine the sources of visual information used by highly skilled tennis players in anticipating their opponent's shots. In Experiment 1, motion analysis of the strokes showed that the relative motion between the racquet and forearm was different between the ground strokes and lobs, but there were no reliable kinematic differences when shot direction was varied. In Experiment 2, 12 skilled tennis players observed the opponent hitting strokes in a normal video or in a point-light display with different segments occluded. Players' anticipation accuracy was not degraded by the use of the point-light display. Occluding the racquet and forearm significantly reduced the participant's ability to determine the type of stroke produced.  相似文献   

Against the current: A grounded theory study on the estrangement experiences of a select group of Filipino gay older persons     

Allan B. de Guzman  Les Paul Valdez  Maverick B. Orpiana  Nikki Angela F. Orantia  Patrick Van E. Oledan  Karla Monica Cenido 《Educational gerontology》2017,43(7):329-340

According to Healthy People (2011), in order to understand the health concerns of the Lesbian, Gay, Bisexual, and Transgender (LGBT), the oppression and discrimination that they have faced must be scrutinized. Among the many issues they face, their estrangement experiences are one of the most understudied. However, little is known about how it is experienced by the gay elderly population, hence, this investigation. This grounded theory purports to describe the process by which estrangement is experienced among the Filipino gay older adults. Strauss and Corbin’s Grounded Theory (1990) design was utilized. A total of 10 gay older persons were purposively chosen to participate in semi-structured interviews. Field texts were subjected to thematic analysis involving open, axial, and selective coding. The study generated The Sailing Model of Estrangement. Remarkably, three phases relative to estrangement emerged, namely: sequestering, striving, and surviving. Primarily, the sequestering phase involves the gay persons’ need to express self, search for acceptance, and its subsequent reactions. The striving phase typifies the struggle in dealing with estrangement leading to either feelings of depression, remorse and shame or positivity, hopefulness, and motivation. Finally, in the surviving phase, gay persons may either feel contented and fulfilled or sad, lonely, and remorseful as they acquiesce aging with estrangement. Findings of the study offer an understanding of how Filipino gay older adults employ coping strategies in response to estrangement.  相似文献   

Child abuse potential in parents with histories of substance use disorder     

Ammerman RT  Kolko DJ  Kirisci L  Blackson TC  Dawes MA 《Child abuse & neglect》1999,23(12):1225-1238

OBJECTIVE: To examine the relationship between parental history of substances use disorders (SUDs) and abuse potential. METHOD: Milner's (1986) Child Abuse Potential Inventory (CAPI) was administered to fathers and mothers (with and without histories of SUDs) of 10- to 12-year-old boys. RESULTS: Fathers and mothers with lifetime histories of SUDs had higher Abuse Scale scores and were more likely to score in the Elevated range (as determined by clinically significant cutoff scores) than parents without such histories. No differences were found between parents with current diagnoses of SUD and those with past (but not current) histories of SUD. Fathers and mothers with a partner who had a history of SUD were more likely to score in the Elevated range, regardless of their own SUD histories. Separate regression models revealed that, for both fathers and mothers, emotional dysregulation (positive and negative affectivity) predicted Abuse Scale scores. Additional contributors to Abuse Scale scores were SUD status in fathers, and lack of involvement with the child in mothers. CONCLUSIONS: History of SUDs in both fathers and mothers increases abuse potential. Contributors to abuse potential differed in fathers and mothers, underscoring the importance of examining parents separately in child maltreatment research.  相似文献   

The development of pattern recognition ability in children     

Les Sternberg  Paul Larson 《Contemporary educational psychology》1976,1(2):146-156

Pattern recognition development was studied in high and low ability preschool, kindergarten, and first-grade youngsters. Pattern recognition was assessed by the administration of 96 pattern tasks which measured the ability of a youngster to find: (a) duplicate patterns and elements to a model; (b) the opposite pattern to a model; and (c) duplicate patterns but different elements than in the model. Aside from main effects for grade level, ability level, and pattern task, a significant three-way interaction was noted. This interaction was analyzed in terms of its component simple effects. The implication of these simple interaction effects for Piagetian theory and educational practice were discussed.  相似文献   

Comparing the pre- and post-impact ball and racquet kinematics of elite tennis players' first and second serves: a preliminary study   总被引：1，自引：0，他引：1  

Chow JW  Carlton LG  Lim YT  Chae WS  Shim JH  Kuenster AF  Kokubun K 《Journal of sports sciences》2003,21(7):529-537

The aim of this study was to compare the pre- and post-impact three-dimensional kinematics of the ball and racquet during first and second serves performed by elite tennis players. Data were collected from four male and four female right-handed professional players during competition using two high-speed cameras (200 Hz). For each player, one first serve and one second serve from the 'deuce' or right service court that landed within the specified target area were analysed. To test for significant differences between the first and second serves, Wilcoxon tests (P < or = 0.05) were performed on selected parameters. The results indicate that the ball travelled forward and to the left during the flight phase of the toss in all but one trial. The average pre-impact ball forward location for the first serve was significantly more in front and had a higher associated forward ball velocity than the corresponding values for the second serve. On average, the decrease in post-impact ball speed from the first to the second serve was 24.1%. No significant differences between the first and second serves were found in the pre-impact racquet head speed and orientation, which was represented as a unit vector perpendicular to the racquet face. The major adjustments made by the players when going from the first to second serve were a decrease in pre-impact ball forward location (P < or = 0.01) and an increase in the pre-impact racquet vertical and lateral velocities (both P < or = 0.05). This implies that the players tossed the ball closer to the body and imparted topspin and sidespin on the ball by changing the racquet vertical and lateral velocities when going from the first to the second serve.  相似文献   

Endurance training adherence in elite junior netball athletes: a test of the theory of planned behaviour and a revised theory of planned behaviour     

Palmer CL  Burwitz L  Dyer AN  Spray CM 《Journal of sports sciences》2005,23(3):277-288

This study examined the utility of Ajzen's (1985) theory of planned behaviour and Maddux's (1993) revised theory of planned behaviour to predict endurance training intentions and adherence of elite junior netball athletes. One hundred and fifteen athletes from the England Netball World Class Start Programme were assessed on constructs central to the predictions of the two theories. Adherence to a recommended endurance training programme was recorded in self-report diaries across a 9-week period. Validity for the diaries was supported by significant correlations (P < 0.001) with recalls across 7 days and 9 weeks. Adherence was moderate and variable between athletes (mean = 66.05, s = 25.75%). Two separate path analyses were conducted to examine the predictions of the theories. Goodness-of-fit indices suggested acceptable fit of the data to the models. Analyses showed that attitude towards the new behaviour, subjective norms and perceived behavioural control predicted training intentions. The relationship between intention and adherence was weak. The present results suggest that the constructs of the theory of planned behaviour offer some insight into the explanation of intentions to follow an endurance training programme. Constructs unique to the revised theory of planned behaviour did not significantly predict training intentions or behaviour. Implications for practitioners working with team sport performers are provided.  相似文献   

From Symphony to Jazz: The concept of strategy in education     

Les Bell 《School Leadership & Management》2013,33(4):449-460

This paper considers the derivation of the concept of strategy and its deployment as a management technique to enable organisations to prepare for the future. It then examines the related growth of school development planning and explores the extent to which this can be considered to be strategic. It is then argued that whether or not school development planning is strategic, the use of strategy in organisations is no longer either possible, if it ever was, or appropriate. The paper concludes by proposing an alternative basis for planning derived from a combination of marginal incrementalism and feminist literature on problem solving.  相似文献   

How autonomy support and ethical value alignment influences attitudes towards diversity in English police     

Maya Al-Khouja  Les Graham  Netta Weinstein  Yuyan Zheng 《Journal of moral education》2020,49(3):365-380

ABSTRACT

Antagonism towards diversity, an attitude reflecting low egalitarian ethical values, has been a topic within policing that has received increasing attention in the last decade. Using two-wave data and applying self-determination theory, we investigated how autonomy support versus autonomy frustration, ways of being motivated either through encouraging one’s sense of volition, or otherwise, coercing and imposing pressures, can improve diversity attitudes through its relation with ethical values. Study 1 (n= 398 police officers and staff) found that autonomy-supportive communications fostered ethical values, and hence was negatively related to diversity antagonism. Study 2 (n= 859 police officers and staff) indicated that motivation to overcome prejudice mediates the relationship between ethical values and diversity antagonism. Perceptions of workplace culture as lacking in autonomy support acted as a boundary condition for the ethical values and diversity antagonism relationship; no relationship was present when autonomy support was low.  相似文献   

Children: Ethnic and Political Violence-a Commentary   总被引：2，自引：0，他引：2  

Ed Cairns  y Dawes 《Child development》1996,67(1):129-139

The articles in this special section add significantly to our knowledge about the impact of ethnic and political violence on children. At the same time, these studies also illustrate some of the problems in this area and, in particular, draw attention to the many methodological difficulties researchers face in this domain. In this commentary, the authors consider both the contributions and limitations of the investigations included in this section, and make suggestions as to how the field may advance in the next decade.  相似文献   

Middle Schools: the heart of schools in crisis     

Gwen Wallace  Les Tickle 《British Journal of Sociology of Education》1983,4(3):223-240

This paper is about middle schools and the effects of recent policies on the curricula organisation of six of them. We begin by establishing some general links between middle school origins, brief history and development, and wider economic and political forces for change. Drawing on four years of research with a group of schools in one local authority, we describe some of the directions of change which followed the Great Debate. We highlight recent changes as these schools came under increasing bureaucratic control, with the emphasis on the organisation of pupil selection and changes from mixed ability grouping, to setting, and back to mixed ability groups. We conclude with some theoretical discussion related to the work of Habermas.  相似文献