Kinematic and kinetic analysis of overhand,sidearm and underhand lacrosse shot techniques

Lacrosse requires the coordinated performance of many complex skills. One of these skills is shooting on the opponents’ net using one of three techniques: overhand, sidearm or underhand. The purpose of this study was to (i) determine which technique generated the highest ball velocity and greatest shot accuracy and (ii) identify kinematic and kinetic variables that contribute to a high velocity and high accuracy shot. Twelve elite male lacrosse players participated in this study. Kinematic data were sampled at 250 Hz, while two-dimensional force plates collected ground reaction force data (1000 Hz). Statistical analysis showed significantly greater ball velocity for the sidearm technique than overhand (P < 0.001) and underhand (P < 0.001) techniques. No statistical difference was found for shot accuracy (P > 0.05). Kinematic and kinetic variables were not significantly correlated to shot accuracy or velocity across all shot types; however, when analysed independently, the lead foot horizontal impulse showed a negative correlation with underhand ball velocity (P = 0.042). This study identifies the technique with the highest ball velocity, defines kinematic and kinetic predictors related to ball velocity and provides information to coaches and athletes concerned with improving lacrosse shot performance.     

Getting What You Pay For: Children's Use of Market Norms to Regulate Exchanges

Children are sensitive to a number of considerations influencing distributions of resources, including equality, equity, and reciprocity. We tested whether children use a specific type of reciprocity norm—market norms—in which resources are distributed differentially based strictly on amount offered in return. In two studies, 195 children 5–10 years and 60 adults distributed stickers to friends offering same or different amounts of money. Overall, participants distributed more equally when offers were the same and more unequally when offers were different. Although sensitive to why friends offered different amounts of money, children increasingly incorporated market norms into their distributions with age, as the oldest children and adults distributed more to those offering more, irrespective of the reasons provided.     

Thurstone Scale for Measuring Attitudes of College Students toward Physical Fitness and Exercise

Abstract

Employing modified Thurstone techniques, two equivalent forms of an equal-appearing intervals attitude scale were constructed around the topic “physical fitness and exercise.” Experimental test items were subjected to an extensive refinement process preceding the formulation of the final alternate test forms. Validity of the test was based upon authoritative opinion and expert judgment. A reliability coefficient derived from test, retest sampling was .83 ± .06. A correlation coefficient of .87 ± .03 was obtained on the parallel lest forms.     

College/University Counseling Centers Supporting Study Away: Challenges and Opportunities

Research points to significant numbers of students on college campuses experiencing mental health distress and an ever increasing number of college students who are choosing to make an off-campus educational experience a part of their college careers. When we consider both of these trends together, it is quite apparent that a significant number of students with mental health concerns will spend periods of time studying away from campus, with converging concerns among college mental health and study away professionals about how to best support these students. This article seeks to outline both challenges and opportunities inherent in the collaboration between campus professionals in supporting students with mental health issues before and during their study away experiences.     

“Students Get What Flows Downward”: District Leaders’ Rationalizations of the Standardized Testing of Children

What do students stand to gain from high-stakes, standardized testing? We consider answers to this question from the perspective of urban district leaders tasked with designing and overseeing the implementation of standardized testing policies. Results revealed variation in leaders’ framing of and rationale for standardized testing with respect to benefits for students and whether/why students should strive for high test scores. Implications for both approaches to standardized testing and broader improvement initiatives are discussed.     

The elaboration theory of instruction: A model for sequencing and synthesizing instruction

This paper describes a novel instructional model for sequencing, syntheizing, and summarizing subject-matter content. The importance of such models is discussed, along with the need for a significant change in the role of subject-matter structure in instruction. A zoom-lens analogy is presented to facilitate an understanding of the elaboration model of instruction. Some basic concepts and principles upon which the model is based are described. The basic unvarying components of the elaboration model are described. And finally, some variations in the model for different kinds of goals are described. The elaboration model follows a general-to-detailed pattern of sequencing, as opposed to the hierarchically based sequences derived from Gagné-type task analyses.Many of the ideas described in this paper were developed under two projeets, one funded by Brigham Young University in Provo, Utah, and the other by the Navy Personnel Research and Development Center in San Diego, California; however, the ideas expressed do not necessarily constitute the opinions of the funding institutions.