The aim of this study was to compare the arm-to-leg coordination in the butterfly stroke of three groups of male swimmers of varying skill (10 elite, 10 non-elite, and 10 young swimmers) at four race paces (400-m, 200-m, 100-m, and 50-m paces). Using qualitative video analysis and a hip velocity-video system (50 Hz), key events of the arm and leg movement cycles were defined and four-point estimates of relative phase were used to estimate the arm-to-leg coordination between the propulsive (pull and push of arms and downward movement of leg undulation) and non-propulsive phases (entry, catch, and recovery of arms and upward movement of leg undulation). With increasing race pace, the velocity, stroke rate, and synchronization between the arm and leg key points also increased, indicating that velocity and stroke rate may operate as control parameters. Finally, these changes led to greater continuity between the propulsive actions, which is favourable for improving the swim velocity, suggesting that coaches and swimmers should monitor arm-to-leg coordination. 相似文献
In this paper the special problems and needs of disabled adults during vocational rehabilitation in rehabilitation centers will be analyzed. For this purpose, the goals and measures of ideal counseling in regard to vocational choice, work and training adjustment, and social adjustment are compared with the results of evaluation studies and studies with drop-outs of these facilities. Conclusions are derived by which measures counselors can contribute essentially to the disabled trainees being better enabled to handle their adjustment problems more effectively.Paper presented at the International Round Table for the Advancement of Counseling Consultation on Counseling Disabled People and their Families, July 4–8, 1987, Vienna, Austria. 相似文献
This study examined arm and leg coordination and propulsion during the flat breaststroke in nine elite male and eight elite female swimmers over three race paces (200 m, 100 m and 50 m). Coordination was expressed using four temporal gaps (T1, T2, T3, T4), which described the continuity between the propulsive phases of the limbs, as recorded on a video device (50 Hz). Glide duration was denoted T1, the time between the beginning of arm and leg recovery was denoted T2, the time between the end of arm and the leg recovery was denoted T3, and the time between 90 degrees of flexion during arm recovery and 90 degrees during leg recovery was denoted T4. Using these temporal gaps, four stroke phases (propulsion, glide, recovery and leg insweep) could be followed over a complete arm and leg stroke. The total duration of arm and leg propulsion was assessed by a new index of flat breaststroke propulsion (IFBP). Velocity, stroke rate and stroke length were also calculated for each pace. The elite swimmers showed short T2, T3 and T4; moreover, T1 decreased when the pace increased. Expertise in the flat breaststroke was thus characterized by synchronized arm and leg recoveries and increased continuity in the arm and leg propulsions with increasing velocity. Differences between the sexes in the spatio-temporal parameters were possibly due to anthropometric differences (the men were heavier, older and taller than the women) and different motor organization linked to arm and leg coordination (shorter T3, body glide and body recovery, and greater body propulsion and higher IFBP in the men). The men's propulsive actions showed greater continuity, particularly in the sprint. The best men adopted a superposition coordination and thus had the ability to overcome very great active drag. Temporal gap measurement and the IFBP are practical indicators of arm and leg coordination and propulsion that can be exploited by coaches and swimmers to increase the continuity between propulsive actions during the flat breaststroke. 相似文献
This paper analyses whether complementarity and substitutability of knowledge elements are key determinants of the firm's inventive performance, in addition to the more conventional measures of knowledge stock and diversity. Using patent data from 1968 to 2002 in the semiconductor industry, we find that the overall level of complementarity between knowledge components positively contributes to firms’ inventive capability, whereas the overall level of substitutability between knowledge components generally has the opposite effect. Yet a relatively high level of substitutability is found to be beneficial for explorative inventions. These results suggest that a firm's inventive capacity significantly depends on its ability to align its inventive strategies and knowledge base structure. 相似文献
Unlike many other growth factors, neurotrophic factors do not stimulate the general proliferation of nerve cells but rather differentiation, both morphologically and biochemically. Recent research, including nerve cell cultures, has done much to reveal the nature and mode of actions of these factors and suggests ways in which they might be used in clinical medicine. 相似文献
The UK higher education sector has entered a period of turbulence, as the consequences of the UK leaving the European Union (EU) hit home. Higher education institutions are bracing themselves for what will no doubt be a period of substantial change, uncertainty and challenge. The complexity of the intricate relationships linking EU member states, as well as the EU institutions and their member states, appears to have been misunderstood and understated in the UK, by both the political class and the general public, at the time of the June 2016 referendum. If information is indeed power, its current unavailability is a concern, given that the UK government’s plans to remain firmly embedded within the European Research Area and the Erasmus+ programme remain non-committal. In what can be described as a game of high politics between the EU and the UK government, the fate of research and higher education collaboration will be sealed by high-level inter-governmental agreements decided behind closed doors.
Three experiments investigated the role of source information (i.e., who said what) in readers’ comprehension of short informational texts. Based on the Discrepancy-Induced Source Comprehension assumption (Braasch, Rouet, Vibert, & Britt, 2012), we hypothesized that readers would be more likely to make use of source information when summarizing stories that included discrepant statements. Readers would also memorize source information more accurately. Experiments 1 and 2 found that American and French college students were more likely to refer to source information when they summarized news reports containing discrepant assertions. A detailed content analysis of the summaries also indicated that students use hedging and several other tactics to resolve contradictions. Experiment 3 replicated Braasch et al.’s finding that sources of discrepant stories were more likely to be recalled than sources of consistent stories. Experiment 3 also extended these findings using longer texts and a different reading task. Altogether the data support the Documents Model framework of multiple source comprehension. 相似文献