Elite tennis player sensitivity to changes in string tension and the effect on resulting ball dynamics

Eighteen elite male tennis players were tested to determine their ability to identify string tension differences between rackets strung from 210 N (47 lb) to 285 N (64 lb). Each player impacted four tennis balls projected from a ball machine before changing rackets and repeating the test. Eleven participants (61%) could not correctly detect a 75 N (17 lb) difference between rackets. Only two participants (11%) could correctly detect a 25 N (6 lb) difference. To establish whether varying string tensions affected ball rebound dynamics, the ball’s rebound speed and landing position were analysed. The mean rebound ball speed was 117 km h⁻¹, with only the trials from the 210 N racket producing significantly lower (P < 0.05) rebound speeds than the 235 N and 260 N rackets. This is contrary to previous laboratory-based tests where higher rebound speeds are typically associated with low-string tensions. The anomaly may be attributable to lower swing speeds from participants as they were not familiar with such a low string tension. Ball placement did not appear related to string tension, with the exception of more long errors for the 235 N racket and fewer long errors for the 285 N racket. It was concluded that elite male tennis players display limited ability to detect changes in string tension, impact the ball approximately 6% faster than advanced recreational tennis players during a typical rallying stroke, and that ball placement is predominantly unrelated to string tension for elite performers.     

Perceived submaximal force production in young adults

The purpose of this investigation was to examine the force production patterns using perceived stimulus cues from 10% to 90% of maximal force. In Experiment 1, 54 men (age: 19-34 years) and 53 women (age: 18-37years) performed leg extensions on a dynamometer at a speed of 60 degrees/s. Participants produced actual forces perceived to be 10-90% of maximal force in 10% increments followed by a maximal force. A 2-min rest interval was maintained between each increment. Participants rested 5 min and repeated the protocol. Desired forces were calculated as the required percentage of the produced maximalforce. In Experiment 2, 40 men (age: 18-30years)followed the protocol ofExperiment 1, but the submaximal stimuli were randomly presented. In Experiment 1, test-retest results indicated consistency between the trials for actual and maximal force (r = .90). The correlations between actual and desired forces were moderately high (r > .76). Actual forces trended above desired forces at 10% of maximal, with median errors ranging 33-40% for men and 60-73% for women. From 30% to 90% of maximal forces, actual trended below desired forces, with median errors ranging from a low of 1.5% to a high of 37%. A power function analysis relating the change in actual force with desired force stimuli produced exponents of 0.68 (.95 CI = 0.62-0.74) for men and 0.5 7 (.95 CI = 0.52-0.62)for women. Findings were similar in Experiment 2, indicating that individuals tended to overshoot and then undershoot desired force production through perceptual force ranges of 10-90% of maximal forces and that force production grew more slowly than perceptual stimulus cues. The results of the present study, along with findings from past research, indicate that production of submaximal force using perceptual cues or stimuli display a great deal of specificity. This specificity is related to type of contraction, amount of muscle mass involved, and number and types of stimuli.     

Inviting Conversations? Dialogic difficulties in the corporate university

The paper experiments with, and reflects on, the limited possibilities for collaboration and communication across disparate groups within the university setting. The authors respond to the strong imperative to bring management, academics and support staff together, and so move beyond the entrenched positions and interests that those groups often display. They highlight the implications that this may have for collaborative academic publication. The text of the paper works as a research exercise in which each author's contribution constitutes data as well as providing reflections upon their own distinct identity and its consequences for communication in universities. The authors argue that attempts to enact ‘better communication’ is in many senses a failed project, but that it is this very fact which makes the experiment instructive. They conclude that calls to collaboration must acknowledge the fact that such relationships will always be relations of power, and are therefore not easily negotiated or understood.     

Psychometric Characteristics of the Revised Procrastination Inventory

The Procrastination Inventory developed for use with doctoral students in clinical psychology was modified for use with ABD students and doctoral graduates in a College of Education. The original Procrastination Inventory contained 43 items with 11 subscales. The structure of the revised measure was analyzed both through factor and Rasch analyses and three subscales that were more generalized were found instead of the eleven originally posited. The three subscales were: (1) procrastination, 20 items, alpha = .88, (2) perfectionism, 9 items, alpha = .64, and (3) graduate school comfort, 6 items, alpha = .59. Eight items were deleted after Rasch and factor analyses, resulting in a 35-item scale. Validity was demonstrated by the measure's ability to predict dissertation completion and through correlations with related measures. The Procrastination Inventory is useful in the study of attrition from doctoral programs, particularly at the dissertation stage.     

Decreasing attention deficit hyperactivity disorder symptoms utilizing an automated classroom reinforcement device

Psychologists and physicians are frequently approached by parents and, indirectly, by classroom teachers to diagnose and treat Attention Deficit Hyperactivity Disorder. Requests are also frequently made for psychostimulant medication to control ADHD behavioral symptoms. One reason for such requests is that alternative classroom approaches to treating ADHD have focused on positive reinforcement, response cost, and token reinforcement programs, all of which can require extensive teacher involvement. One of the major problems with such behavioral approaches is the fact that teachers have limited time to reinforce positive, attentive behaviors, and/or alternative behaviors to ADHD symptoms. This study examined the efficacy of an automated reinforcement device, the Attention Training System (ATS), in decreasing off-task behavior in an 11-year-old, fifth-grade student who had been diagnosed as being affected with ADHD and had been placed in Special Education Resource Room programming. The Attention Training System provides automated token reinforcement in the form of points on a fixed interval schedule when the youngster is on-task. When distractible, impulsive, or hyperactive behavior occurs, the Attention Training device can be activated by a teacher to provide a response-cost consequence of loss of points. The device in this study was coupled with a token reinforcement program whereby points could be exchanged for selected reinforcers at the end of each day. Results indicated that the ATS plus token reinforcement was successful in reducing off-task behavior across classes of three subject areas: Science, Reading, and Social Studies. Results have implications for psychologists and physicians in their attempts to assist families and schools in their management of youngsters with ADHD.     

The Effectiveness of an Initial Teacher Training Partnership in Preparing Students to Teach Art in the Primary School

Recent government reform of initial teacher education has increased teachers’ responsibility for training students in schools, bringing about some fundamental changes in the professional relationship between the schools, higher education institutions (HEIs), teachers and students. This paper reports on primary undergraduate student teachers’ and their class teachers’ perceptions of school-based training to teach art. Class teachers were interviewed about their preparedness to train students and questionnaires and interviews were used to gauge students’ views of the effectiveness of university-based courses and the support given to them by teachers. The findings indicate that teachers were able to support students in matters of classroom management and resources but that they were mostly unable to assist them in developing subject knowledge and understanding of art teaching and learning. This raises concerns about teachers’ subject knowledge and their confidence in training students. Our findings suggest that there is significant room for improvement in the partnership arrangements between schools and HEIs in order to better support students’ teaching of art.     

The rough theatre of science teaching in the compulsory years rationality & artistry

Research in Science Education -