Ball launch conditions for skilled golfers using drivers of different lengths in an indoor testing facility

Abstract

The displacement of the golf ball struck by a driving club is affected by several player characteristics and equipment parameters and their interrelationships. Some modelling and simulation studies have shown a relationship between shaft length and clubhead speed, supported by a few experimental studies. The aim of the present study was to examine the relationship between driver length and ball launch conditions in an indoor test facility using a ball launch monitor. Nine males considered to be skilled golfers participated in the study. Four driving clubs of total length 117, 119, 124, and 132 cm were assembled from commercially available components and were used to strike golf shots while initial ball velocity, backspin rate, and launch angles were measured. Statistical analysis identified a significant difference in initial launch speed due to club length, a significant difference between participants, but no difference between the trials for a given golfer. A positive trend was noted between backspin and launch angle for all four clubs, and significant inverse associations between initial launch speed and backspin rate and launch angle. However, the combined launch conditions associated with increasing length were not considered optimal, with uncontrolled swingweight and moment of inertia effects considered to be limiting factors.     

Determination of the swing technique characteristics and performance outcome relationship in golf driving for low handicap female golfers

Abstract

Previous studies on the kinematics of the golf swing have mainly focused on group analysis of male golfers of a wide ability range. In the present study, we investigated gross body kinematics using a novel method of analysis for golf research for a group of low handicap female golfers to provide an understanding of their swing mechanics in relation to performance. Data were collected for the drive swings of 16 golfers using a 12-camera three-dimensional motion capture system and a stereoscopic launch monitor. Analysis of covariance identified three covariates (increased pelvis–thorax differential at the top of the backswing, increased pelvis translation during the backswing, and a decrease in absolute backswing time) as determinants of the variance in clubhead speed (adjusted r ² = 0.965, P < 0.05). A significant correlation was found between left-hand grip strength and clubhead speed (r = 0.54, P < 0.05) and between handicap and clubhead speed (r = ?0.612, P < 0.05). Flexibility measures showed some correlation with clubhead speed; both sitting flexibility tests gave positive correlations (clockwise: r = 0.522, P < 0.05; counterclockwise: r = 0.711, P < 0.01). The results suggest that there is no common driver swing technique for optimal performance in low handicap female golfers, and therefore consideration should be given to individual swing characteristics in future studies.     

The relevance of innovative school architecture for school principals

In many cases, innovative forms of learning require innovative concepts of using space in school. However, so far there has been a lack of research concerning the perspectives of school principals as important stakeholders in the adoption of alternative school architecture. The present study examines the importance of alternative school architecture in a sample of 1164 principals (56% females, mean-age 52.7 years) in Austria. An online questionnaire was conducted, containing questions about the school building, innovative forms of learning, and principals’ level of information, perceptions, and thoughts on the relevance of school architecture, as well as their motivation and self-efficacy. Results showed that principals are aware of the advantages of certain architectural elements, although these elements have been implemented in only a few schools. A high proportion of respondents report a lack of information about configurations of space that go beyond the traditional corridor-scheme. We conclude that although principals are in general open for the alternative configuration of space further efforts have to be made to overcome the obstacles that prevent principals from launching new concepts of using space, which are a lack of competitive resources and knowledge as well as an inadequate professional network.     

Assessing semantic-syntactic features of verbs from thirteen verb subsets

There are three major classes of verbs: intransitive, transitive, and linking. These three types of verbs can be divided into 13 semantic-syntactic subsets. Verbs within each subset give rise to sentences that have similar syntactic form, albeit a form distinct from that of sentences associated with other subsets. Preliminary research found that more than 90% of sentences written by children or for children contain verbs from 1 of the 13 verb subsets. The sentence form associated with each verb subset might be viewed as a "sentence template" that operationally defines a fixed set of 13 underlying semantic-syntactic relationships essential to communication. A strategy for assessing a child's knowledge of verbs from each subset is described.     

Building classroom community at a distance: A case study

The purpose of this study was to analyze a five-week graduate-level education course taught entirely at a distance via the Internet using the Blackboard.com^SM e-learning system, with emphasis on exploring the dynamics of sense of classroom community. Subjects were 20 adult learners, evenly divided between males and females, who were administered the sense of classroom community index at the beginning and end of the course in order to measure classroom community. Findings indicated that on-line learners took advantage of the “learn anytime” characteristics of the Internet by accessing the course seven days per week, 24 hours per day. Sense of classroom community grew significantly during the course. Females manifested a stronger sense of community than their male counterparts both at the start and end of the course. Additionally, female students exhibited a mostly connected communication pattern while the communication pattern of males was mostly independent.     

Positive behavioral contrast,autoshaping, and omission responding in the goldfish (Carassius auratus)

Two experiments with goldfish were performed to investigate the role of stimulus-reinforcer vs. response-reinforcer relationships in omission training and the role of stimulus localizability in a positive behavioral contrast paradigm. The directed behavior of fish, like that of pigeons and rats in other studies, was greatly influenced by positive stimulus-reinforcer correlations, as evidenced by maintained contacts of a signal for food, even though such responses terminated the signal and cancelled reinforcement delivery. Goldfish exhibited positive behavioral contrast when the signals for reinforcement and nonreinforcement were displayed directly on the response key, but no contrast was observed when variations in a diffuse houselight stimulus were used as signals for reinforcement or nonreinforcement. Analysis of sequential-trial data yielded effects analogous to Pavlovian positive and negative induction. Theoretical and methodological problems were briefly considered.     

Behavior Problems and Social Skills in Preschool Children: Parent-Teacher Agreement and Relations with Classroom Observations

The goals of the present investigation were to provide basic psychometric information about the use of the Preschool and Kindergarten Behavior Scales (PKBS: Merrill, 1994) with a sample of normally-developing preschool children, to assess agreement between parent and teacher ratings of children on this instrument, and to assess concurrent, criterion-related validity of these instruments in terms of their relations with observations of children's behavior in the classroom. Parents and teachers of 47 preschool children completed the scales and these children were observed naturalistically in the classroom setting. Overall, agreement between parents and teachers was modest (-.09 to .38). Cross-informant correlations were poor (-.09 to .27) for social skills, low (.15 to .36) for internalizing behaviors, and modest (.29 to .38) for externalizing behavior. Both parents and teachers rated boys as having more externalizing behavior problems than girls. Parents perceived their children to have more externalizing, and more overall, behavior problems than did teachers. In general, teacher reports, but not parent reports, were significantly associated with children's independently observed goal-directed activity, sustained attention, inappropriate behavior, peer affiliation, expressed negative affect, and proximity to a teacher in the classroom. Results argue for the clinical utility of the PKBS for teacher-report assessment of child behavior problems and social skills in the preschool years, and suggest the need for cross-contextual assessment. Also, it is clear that children's behavioral and social competence are crucial for optimal functioning in the preschool setting.     

Turnaround time and market capacity in contract cheating

Contract cheating is the process whereby students auction off the opportunity for others to complete assignments for them. It is an apparently widespread yet under-researched problem. One suggested strategy to prevent contract cheating is to shorten the turnaround time between the release of assignment details and the submission date, thus making it difficult for students to make arrangements with contractors. Here, we outline some characteristics of the current market for contract cheating and demonstrate that short turnaround times are unlikely to prevent contract cheating because requested turnaround times for university-level assignments completed via contract cheating are already short (average 5?days). In addition, for every contractor awarded a job, there are an average of 10 others offering to complete it within the specified time suggesting that there is abundant excess capacity in the market.