The Effects of Experience on the Detection and Location of Performance Differences in a Gymnastic Technique

Abstract

Four hundred male subjects between the ages of 8 and 83 were measured for reaction time and movement time. A statistical analysis of the data permits the conclusion that reaction time and movement time are significantly related.     

Markers of isometric training intensity and reductions in resting blood pressure

Abstract

In this study, we examined the correlations between selected markers of isometric training intensity and subsequent reductions in resting blood pressure. Thirteen participants performed a discontinuous incremental isometric exercise test to volitional exhaustion at which point mean torque for the final 2-min stage (2min-torque_peak) and peak heart rate peak (HR_peak) were identified. Also, during 4 weeks of training (3 sessions per week, comprising 4 × 2 min bilateral leg isometric exercise at 95% HR_peak), heart rate (HR_train), torque (Torque_train), and changes in EMG amplitude (ΔEMG_amp) and frequency (ΔEMG_freq) were determined. The markers of training intensity were: Torque_train relative to the 2min-torque_peak (%2min-torque_peak), EMG relative to EMG_peak (%EMG_peak), HR_train ΔEMG_amp, ΔEMG_freq, and %MVC. Mean systolic (?4.9 mmHg) and arterial blood pressure (?2.7mmHg) reductions correlated with %2min-torque_peak (r = ?0.65, P = 0.02 and r = ?0.59, P = 0.03), ΔEMG_amp (r = 0.66, P = 0.01 and r = 0.59, P = 0.03), ΔEMG_freq (r = ?0.67, P = 0.01 and r = ?0.64, P = 0.02), and %EMG_peak (systolic blood pressure only; r = ?0.63, P = 0.02). These markers best reflect the association between isometric training intensity and reduction in resting blood pressure observed after bilateral leg isometric exercise training.     

Analysis and modification of verbal coaching behaviour: The usefulness of a data‐driven intervention strategy

This study tested a computer‐aided coaching analysis instrument (CAI) as part of an intervention strategy designed to modify verbal coaching behaviour. Four coaches were observed and analysed over 12 practice sessions. Coaches A, B and C received intervention feedback through CAI data, where selected behaviours were highlighted for discussion, and videotape images were used to illustrate discussion points. Coach D was provided with videotapes of his own performance and told to formulate and implement any of his own recommendations. The CAI data are primarily quantitative, so target values were created for the different dimensions of verbal behaviour. This benefited the coaches in interpreting their effectiveness and provided a reference to evaluate the magnitude of change. Written journals and audiotape recordings were also used to promote insight into the complexity of verbal behaviour and the ‘human factors’ (e.g. relationship with players, attitude to researcher) that affect behaviour modification.

Instructional effectiveness was assessed by time‐series analysis. There was evidence from each behaviour dimension that change can occur and be maintained as a result of exposure to the CAI intervention strategy. However, this is clearly contingent upon the coach understanding what is asked of him or her, and remains focused and committed to changing these particular behaviours. The analysis of Coach D's behavioural change suggests there are limitations to the sensitivity of discretionary viewing, as only two dimensions of behaviour were identified for, and resulted in, positive change. The results of this study provide support for Locke's (1984) contention that behaviour modification can occur by using data as direct feedback, as reinforcement and as information in the form of recommendations. However, the study also illuminates several factors that can negate the modification and maintenance of verbal coaching behaviour.     

Children's Perception of Proportion in Graphs

Children ranging in age from 9 to 13 years made judgments of proportion with a variety of graphical elements in 2 experiments. Younger children can be misled by irrelevant dimensions of objects used to portray magnitudes and proportions, but older children make their judgments like adults, ignoring or accommodating the extra dimensions. Although the psychophysical function for older children and adults is approximately linear, closer inspection reveals a complex pattern of bias that is not captured by traditional psychophysical models. A characteristic pattern of over- and underestimation was observed and also turns out to be present, but previously unnoticed, in judgments made by adults. The pattern of bias is consistent with the view that the visual system extracts real or virtual axes of symmetry and that subjects use these, in addition to the object boundaries, as points of reference when making their judgments. A model that assumes repulsion of judgments away from these reference points is described and fitted to the children's data. The model is motivated by both neurophysiological and cognitive considerations.     

Alternatives to the behavioural technicist conception of study skills

The what and how of study skills programmes are critiqued and alternatives suggested. Due to the absence of information about higher level learning, study skills courses have traditionally focused on study behaviours, rather than upon the cognitive processes involved in mastering complex material. By providing knowledge about the cognitive skills and strategies involved in the acquisition and organization of high level learning, information-processing could form the basis of future learning-skills programmes. Infusing learning skills into the curriculum from a phenomenological-critical theory perspective, means that the study skills counsellor becomes a social change agent aiming for the enlightenment and emancipation of students and lecturers. This is a radical departure from the behavioural-technician remedying a deficit group in a special programme or study laboratory.     

A deniable and efficient question and answer service over ad hoc social networks

When people are connected together over ad hoc social networks, it is possible to ask questions and retrieve answers using the wisdom of the crowd. However, locating a suitable candidate for answering a specific unique question within larger ad hoc groups is non-trivial, especially if we wish to respect the privacy of users by providing deniability. All members of the network wish to source the best possible answers from the network, while at the same time controlling the levels of attention required to generate them by the collective group of individuals and/or the time taken to read all the answers. Conventional expert retrieval approaches rank users for a given query in a centralised indexing process, associating users with material they have previously published. Such an approach is antithetical to privacy, so we have looked to distribute the routing of questions and answers, converting the indexing process into one of building a forwarding table. Starting from the simple operation of flooding the question to everyone, we compare a number of different routing options, where decisions must be made based on past performance and exploitation of the knowledge of our immediate neighbours. We focus on fully decentralised protocols using ant-inspired tactics to route questions towards members of the network who may be able to answer them well. Simultaneously, privacy concerns are acknowledged by allowing both question asking and answering to be plausibly deniable. We have found that via our routing method, it is possible to improve answer quality and also reduce the total amount of user attention required to generate those answers.